add help

54 files changed, 1646 insertions, 1308 deletions

diff --git a/.gitignore b/.gitignore
index e9f2ee4..4bfc3fe 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.depsolver_plt
 *.beam
 test/*_data
 logs
@@ -14,4 +15,4 @@ rebar3
 /.rebar
 rebar.lock
 priv/templates/*.dtl.erl
-ebin/rebar.app
\ No newline at end of file
+ebin
diff --git a/.travis.yml b/.travis.yml
index f0b959e..1eb5935 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,21 @@
 language: erlang
 otp_release:
+  - 17.0
   - R16B02
   - R16B01
   - R15B01
-  - 17.0
-script: "make travis"
+script: make travis
 branches:
   only:
-    - rebar3
\ No newline at end of file
+    - rebar3
+before_deploy: "rm -rf !(rebar3)"
+deploy:
+  on:
+    branch: rebar3
+    condition: $TRAVIS_OTP_RELEASE = R15B01
+  provider: s3
+  access_key_id: AKIAIKQB2JZYYNIWC72Q
+  secret_access_key:
+    secure: JoPSFeISsq7RbkgQLbz/DdLATgGhyuSjjIAwv0lZkhkHspmchArnt9hjDTxmkk8ApPcqDhp8iPEII6E8f2tltTA7djpxx8fO6a7DLyJnDe7QL4Qu1zSMmy91JmkapjDb8VqdAyvUmzAuCp91rfQPsgDiVQNrBSdCfy7LcTZyk3M=
+  bucket: "rebar3"
+  skip_cleanup: true
diff --git a/Makefile b/Makefile
index 8ab2117..2e02370 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,10 @@
-.PHONY: clean dialyzer_warnings xref_warnings deps test
+.PHONY: clean xref_warnings deps test
 
 REBAR=$(PWD)/rebar3
 RETEST=$(PWD)/deps/retest/retest
 
+DEPS_PLT=$(CURDIR)/.depsolver_plt
+
 all:
 	./bootstrap/bootstrap
 
@@ -11,23 +13,24 @@ clean:
 	@rm -f .rebarinfo
 
 distclean: clean
-	@rm -f dialyzer_warnings
 	@rm -rf deps
 
 debug:
 	@./bootstrap/bootstrap debug
 
-check: debug xref dialyzer deps test
+check: debug xref deps test
 
 xref:
 	@./rebar3 xref
 
-dialyzer: dialyzer_warnings
-	@diff -U0 dialyzer_reference dialyzer_warnings
+$(DEPS_PLT):
+	@echo Building local erts plt at $(DEPS_PLT)
+	@echo
+	dialyzer --output_plt $(DEPS_PLT) --build_plt \
+	--apps erts kernel stdlib -r deps
 
-dialyzer_warnings:
-	-@dialyzer -q -nn -n ebin -Wunmatched_returns -Werror_handling \
-		-Wrace_conditions > dialyzer_warnings
+dialyzer: $(DEPS_PLT)
+	dialyzer --fullpath --plt $(DEPS_PLT) -Wno_opaque -Wrace_conditions -r ./ebin
 
 binary: VSN = $(shell ./rebar3 -V)
 binary: clean all
diff --git a/README.md b/README.md
index c1ad571..416fbd9 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ rebar
 rebar is an Erlang build tool that makes it easy to compile and test Erlang
 applications, port drivers and releases.
 
-[![Build Status](https://secure.travis-ci.org/rebar/rebar.png?branch=master)](http://travis-ci.org/rebar/rebar)
+[![Build Status](https://travis-ci.org/tsloughter/rebar.svg?branch=rebar3)](https://travis-ci.org/tsloughter/rebar)
 
 rebar is a self-contained Erlang script, so it's easy to distribute or even
 embed directly in a project. Where possible, rebar uses standard Erlang/OTP
@@ -23,21 +23,24 @@ This is an experimental branch.
 | Command    | Description |
 |----------- |------------ |
 | compile    | Build project |
-| update     | Update package index |
+| clean      | Remove project apps beam files |
+| do         | Higher-order provider to run multiple tasks in sequence |
+| help       | Print help for rebar or task |
+| new        | Create new rebar project from templates |
 | pkgs       | List available packages |
+| release    | Build release of project |
+| tar        | Package release into tarball |
 | shell      | Run shell with project apps in path |
-| escriptize | Create escript from project |
+| update     | Update package index |
+| upgrade    | Fetch latest version of dep |
+| version    | Print current version of Erlang/OTP and rebar |
 
 The following commands are still in the works.
 
 | Command    | Description |
 |----------- |------------ |
-| release    | Build release of project |
-| tar        | Package release into tarball |
-| new        | |
 | eunit      | |
 | ct         | |
-| do         | |
 
 ### Missing
 
@@ -69,8 +72,6 @@ Example:
 -export([init/1,
          do/1]).
 
--include("rebar.hrl").
-
 -define(PROVIDER, something).
 -define(DEPS, []).
 
@@ -78,22 +79,22 @@ Example:
 %% Public API
 %% ===================================================================
 
--spec init(rebar_config:config()) -> {ok, rebar_config:config()}.
+-spec init(rebar_state:state()) -> {ok, rebar_state:state()}.
 init(State) ->
-    State1 = rebar_config:add_provider(State, #provider{name = ?PROVIDER,
-                                                        provider_impl = ?MODULE,
-                                                        bare = false,
-                                                        deps = ?DEPS,
-                                                        example = "rebar something",
-                                                        short_desc = "",
-                                                        desc = "",
-                                                        opts = []}),
+    State1 = rebar_state:add_provider(State, rebar_provider:create([{name, ?PROVIDER},
+                                                                    {module, ?MODULE},
+                                                                    {bare, false},
+                                                                    {deps, ?DEPS},
+                                                                    {example, "rebar dummy"},
+                                                                    {short_desc, "dummy plugin."},
+                                                                    {desc, ""},
+                                                                    {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_config:config()) -> {ok, rebar_config:config()} | relx:error().
-do(Config) ->
+-spec do(rebar_state:state()) -> {ok, rebar_state:state()}.
+do(State) ->
     %% Do something
-    {ok, Config}.
+    {ok, State}.
 ```
 
 
diff --git a/bootstrap/bootstrap b/bootstrap/bootstrap
index 032a08e..83e2b14 100755
--- a/bootstrap/bootstrap
+++ b/bootstrap/bootstrap
@@ -99,7 +99,7 @@ main(Args) ->
 
     %% Add a helpful message
     io:format("Congratulations! You now have a self-contained script called"
-              " \"rebar\" in\n"
+              " \"rebar3\" in\n"
               "your current working directory. "
               "Place this script anywhere in your path\n"
               "and you can use rebar to build OTP-compliant apps.\n").
diff --git a/dialyzer_reference b/dialyzer_reference
deleted file mode 100644
index 6701cb8..0000000
--- a/dialyzer_reference
+++ /dev/null
@@ -1,3 +0,0 @@
-
-rebar_eunit.erl:471: Call to missing or unexported function eunit_test:function_wrapper/2
-rebar_utils.erl:197: Call to missing or unexported function escript:foldl/3
diff --git a/doc/guide.md b/doc/guide.md
new file mode 100644
index 0000000..92df2eb
--- /dev/null
+++ b/doc/guide.md
@@ -0,0 +1,93 @@
+## Why Rebar3?
+
+Rebar was a great step forward for Erlang development but with time has proven to be fragile to change. Rebar3 builds on certain components of rebar which have benefited from years of community collaboration within a new core which is more extendable.
+
+## Creating a New Project
+
+```shell
+$ rebar3 new rel myrelease
+===> Writing apps/myrelease/src/myrelease_app.erl
+===> Writing apps/myrelease/src/myrelease_sup.erl
+===> Writing apps/myrelease/src/myrelease.app.src
+===> Writing rebar.config
+===> Writing relx.config
+===> Writing config/sys.config
+===> Writing config/vm.args
+===> Writing .gitignore
+===> Writing LICENSE
+===> Writing README.md
+```
+
+## Working on an Existing Rebar3 Project
+
+First, checkout the project and change directories to the project root.
+
+```shell
+$ git clone git://github.com/tsloughter/minansan.git
+$ cd minansan
+```
+
+Now we can use rebar3 to fetch all dependencies and build both the dependencies and the project app or apps.
+
+```shell
+$ rebar3 compile
+===> Fetching gproc
+Cloning into '.tmp_dir109479658516'...
+===> Fetching ranch
+Cloning into '.tmp_dir725384773580'...
+===> Fetching cowboy
+Cloning into '.tmp_dir285325769000'...
+===> Fetching cowlib
+Cloning into '.tmp_dir924054839613'...
+===> Compiling gproc
+/home/tristan/Devel/minasan/_deps/gproc/src/gproc_dist.erl:23: Warning: behaviour gen_leader undefined
+===> Compiling cowlib
+===> Compiling ranch
+===> Compiling cowboy
+===> Compiling minasan
+```
+
+## Adding Dependencies
+
+Dependencies are listed in `rebar.config` file under the `deps` key:
+
+```erlang
+{deps, [
+        {cowboy, ".*", {git, "git://github.com/ninenines/cowboy.git", {tag, "1.0.0"}}}
+        ]}.
+```
+
+Then you'll most likely want to add the dependency to one of your project's application's `.app.src` file under applications.
+
+## Rebar3 Conventions
+
+Rebar3 is entirely based on building OTP applications and releases.
+
+* Directories starting with underscores, e.g. `_deps`, are expected to not be checked in version control.
+* Project apps you are working on exist under `apps/` or `lib/`, or is a single app project with `src/` in the root directory.
+* `rebar.lock` and `rebar.config` go in the root of the project.
+* Tests go in `tests/`.
+
+## rebar.config vs rebar.lock
+
+`rebar.lock` contains the exact reference id to a commit that was used to build the project. Committing this file allows you to specify a branch in `rebar.config` for a dependency and still have reproducable builds because if the `rebar.lock` file exists when a rebar3 project is being built the contents of deps in rebar.config are ignored.
+
+## Checkout Dependencies
+
+## Tests
+
+Rebar3 has the concept of test dependencies. These dependencies will only be fetched when a rebar3 command that runs tests is run by the user.
+
+```erlang
+{test_deps, [
+             {meck, ".*", {git, "https://github.com/eproxus/meck.git", {tag, "0.8"}}}
+             ]}.
+```
+
+```shell
+$ rebar ct
+===> Fetching meck
+Cloning into '.tmp_dir772710363032'...
+===> Compiling meck
+===> Compiling minasan
+```
diff --git a/doc/plugins.md b/doc/plugins.md
new file mode 100644
index 0000000..e8f4091
--- /dev/null
+++ b/doc/plugins.md
@@ -0,0 +1,269 @@
+#### TODO ####
+
+- write a rebar3 template for plugin writing, make it easier on our poor souls
+- rework the tutorial to use the rebar3 template for plugins
+
+# Plugins #
+
+Rebar3's system is based on the concept of *[providers](https://github.com/tsloughter/providers)*. A provider has three callbacks:
+
+- `init(State) -> {ok, NewState}`, which helps set up the state required, state dependencies, etc.
+- `do(State) -> {ok, NewState} | {error, String}`, which does the actual work.
+- `format_error(Error, State) -> {String, NewState}`, which allows to print errors when they happen, and to filter out sensitive elements from the state.
+
+A provider should also be an OTP Library application, which can be fetched as any other Erlang dependency, except for Rebar3 rather than your own system or application.
+
+This document contains the following elements:
+
+- [Using a Plugin](#using-a-plugin)
+- [Reference](#reference)
+  - [Provider Interface](#provider-interface)
+  - [List of Possible Dependencies](#list-of-possible-dependencies)
+  - [Rebar State Manipulation](#rebar-state-manipulation)
+- [Tutorial](#tutorial)
+
+## Using a Plugin ##
+
+## Reference ##
+
+### Provider Interface ###
+
+### List of Possible Dependencies ###
+
+### Rebar State Manipulation ###
+
+## Tutorial ##
+
+### First version ###
+
+In this tutorial, we'll show how to start from scratch, and get a basic plugin written. The plugin will be quite simple: it will look for instances of 'TODO:' lines in comments and report them as warnings. The final code for the plugin can be found on [bitbucket](https://bitbucket.org/ferd/rebar3-todo-plugin).
+
+The first step is to create a new OTP Application that will contain the plugin:
+
+    → git init
+    Initialized empty Git repository in /Users/ferd/code/self/rebar3-todo-plugin/.git/
+    → mkdir src
+    → touch src/provider_todo.erl src/provider_todo.app.src
+
+Let's edit the app file to make sure the description is fine:
+
+```erlang
+{application, provider_todo, [
+  {description, "example rebar3 plubin"},
+  {vsn, "0.1.0"},
+  {registered, []},
+  {applications, [kernel, stdlib]},
+  {env, []}
+]}.
+```
+
+Open up the `provider_todo.erl` file and make sure you have the following skeleton in place:
+
+```erlang
+-module(provider_todo).
+-behaviour(provider).
+
+-export([init/1, do/1, format_error/2]).
+
+-include_lib("rebar3/include/rebar.hrl").
+
+-define(PROVIDER, todo).
+-define(DEPS, [app_discovery]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
+init(State) ->
+    Provider = providers:create([
+            {name, ?PROVIDER},          % The 'user friendly' name of the task
+            {module, ?MODULE},          % The module implementation of the task
+            {bare, true},               % The task can be run by the user, always true
+            {deps, ?DEPS},              % The list of dependencies
+            {example, "rebar $PLUGIN"}, % How to use the plugin
+            {opts, []}                  % list of options understood by the plugin
+            {short_desc, ""},
+            {desc, ""}
+    ]),
+    {ok, rebar_state:add_provider(State, Provider)}.
+
+
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+    {ok, State}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+```
+
+This shows all the basic content needed. Note that we leave the `DEPS` macro to the value `app_discovery`, used to mean that the plugin should at least find the project's source code (excluding dependencies).
+
+In this case, we need to change very little in `init/1`. Here's the new provider description:
+
+```erlang
+        Provider = providers:create([
+            {name, ?PROVIDER},       % The 'user friendly' name of the task
+            {module, ?MODULE},       % The module implementation of the task
+            {bare, true},            % The task can be run by the user, always true
+            {deps, ?DEPS},           % The list of dependencies
+            {example, "rebar todo"}, % How to use the plugin
+            {opts, []},              % list of options understood by the plugin
+            {short_desc, "Reports TODOs in source code"},
+            {desc, "Scans top-level application source and find "
+                   "instances of TODO: in commented out content "
+                   "to report it to the user."}
+    ]),
+```
+
+Instead, most of the work will need to be done directly in `do/1`. We'll use the `rebar_state` module to fetch all the applications we need. This can be done by calling the `project_apps/1` function, which returns the list of the project's top-level applications.
+
+```erlang
+do(State) ->
+    lists:foreach(fun check_todo_app/1, rebar_state:project_apps(State)),
+    {ok, State}.
+```
+
+This, on a high level, means that we'll check each top-level app one at a time (there may often be more than one top-level application when working with releases)
+
+The rest is filler code specific to the plugin, in charge of reading each app path, go read code in there, and find instances of 'TODO:' in comments in the code:
+
+```erlang
+check_todo_app(App) ->
+    Path = filename:join(rebar_app_info:dir(App),"src"),
+    Mods = find_source_files(Path),
+    case lists:foldl(fun check_todo_mod/2, [], Mods) of
+        [] -> ok;
+        Instances -> display_todos(rebar_app_info:name(App), Instances)
+    end.
+
+find_source_files(Path) ->
+    [filename:join(Path, Mod) || Mod <- filelib:wildcard("*.erl", Path)].
+
+check_todo_mod(ModPath, Matches) ->
+    {ok, Bin} = file:read_file(ModPath),
+    case find_todo_lines(Bin) of
+        [] -> Matches;
+        Lines -> [{ModPath, Lines} | Matches]
+    end.
+
+find_todo_lines(File) ->
+    case re:run(File, "%+.*(TODO:.*)", [{capture, all_but_first, binary}, global, caseless]) of
+        {match, DeepBins} -> lists:flatten(DeepBins);
+        nomatch -> []
+    end.
+
+display_todos(_, []) -> ok;
+display_todos(App, FileMatches) ->
+    io:format("Application ~s~n",[App]),
+    [begin
+      io:format("\t~s~n",[Mod]),
+      [io:format("\t  ~s~n",[TODO]) || TODO <- TODOs]
+     end || {Mod, TODOs} <- FileMatches],
+    ok.
+```
+
+Just using `io:format/2` to output is going to be fine.
+
+To test the plugin, push it to a source repository somewhere. Pick one of your projects, and add something  to the rebar.config:
+
+```erlang
+{plugins, [
+  {provider_todo, ".*", {git, "git@bitbucket.org:ferd/rebar3-todo-plugin.git", {branch, "master"}}}
+]}.
+```
+
+Then you can just call it directly:
+
+```
+→ rebar3 todo
+===> Fetching provider_todo
+Cloning into '.tmp_dir539136867963'...
+===> Compiling provider_todo
+Application merklet
+    /Users/ferd/code/self/merklet/src/merklet.erl
+      todo: consider endianness for absolute portability
+```
+
+Rebar3 will download and install the plugin, and figure out when to run it. Once compiled, it can be run at any time again.
+
+### Optionally Search Deps ###
+
+Let's extend things a bit. Maybe from time to time (when cutting a release), we'd like to make sure none of our dependencies contain 'TODO:'s either.
+
+To do this, we'll need to go parse command line arguments a bit, and change our execution model. The `?DEPS` macro will now need to specify that the `todo` provider can only run *after* dependencies have been installed:
+
+```erlang
+-define(DEPS, [install_deps]).
+```
+
+We can add the option to the list we use to configure the provider in `init/1`:
+
+```erlang
+{opts, [                 % list of options understood by the plugin
+    {deps, $d, "deps", undefined, "also run against dependencies"}
+]},
+```
+
+Meaning that deps can be flagged in by using the option `-d` (or `--deps`), and if it's not defined, well, we get the default value `undefined`. The last element of the 4-tuple is documentation for the option.
+
+And then we can implement the switch to figure out what to search:
+
+```erlang
+do(State) ->
+    Apps = case discovery_type(State) of
+        project -> rebar_state:project_apps(State);
+        deps -> rebar_state:project_apps(State) ++ rebar_state:src_deps(State)
+    end,
+    lists:foreach(fun check_todo_app/1, Apps),
+    {ok, State}.
+
+[...]
+
+discovery_type(State) ->
+    {Args, _} = rebar_state:command_parsed_args(State),
+    case proplists:get_value(deps, Args) of
+        undefined -> project;
+        _ -> deps
+    end.
+```
+
+The `deps` option is found using `rebar_state:command_parsed_args(State)`, which will return a proplist of terms on the command-line after 'todo', and will take care of validating whether the flags are accepted or not. The rest can remain the same.
+
+Push the new code for the plugin, and try it again on a project with dependencies:
+
+```
+→ rebar3 todo --deps
+===> Fetching provider_todo
+Cloning into '.tmp_dir846673888664'...
+===> Compiling provider_todo
+===> Fetching bootstrap
+Cloning into '.tmp_dir57833696240'...
+===> Fetching file_monitor
+Cloning into '.tmp_dir403349997533'...
+===> Fetching recon
+Cloning into '.tmp_dir390854228780'...
+[...]
+Application dirmon
+    /Users/ferd/code/self/figsync/apps/dirmon/src/dirmon_tracker.erl
+      TODO: Peeranha should expose the UUID from a node.
+Application meck
+    /Users/ferd/code/self/figsync/_deps/meck/src/meck_proc.erl
+      TODO: What to do here?
+      TODO: What to do here?
+```
+
+Rebar3 will now go pick dependencies before running the plugin on there.
+
+you can also see that the help will be completed for you:
+
+```
+→ rebar3 help todo
+Scans top-level application source and find instances of TODO: in commented out content to report it to the user.
+
+Usage: rebar todo [-d]
+
+  -d, --deps  also run against dependencies
+```
+
+That's it, the todo plugin is now complete! It's ready to ship and be included in other repositories.
diff --git a/ebin/rebar.app b/ebin/rebar.app
deleted file mode 100644
index 831567b..0000000
--- a/ebin/rebar.app
+++ /dev/null
@@ -1,32 +0,0 @@
-{application,rebar,
-             [{description,"Rebar: Erlang Build Tool"},
-              {vsn,"3.0.0"},
-              {modules,['LICENSE_dtl','README.md_dtl','app.erl_dtl',
-                        gitignore_dtl,'mod.erl_dtl','otp_app.app.src_dtl',
-                        'otp_lib.app.src_dtl','otp_lib.template_dtl',
-                        'rebar.config_dtl',rebar3,rebar_app_discover,
-                        rebar_app_info,rebar_app_utils,rebar_base_compiler,
-                        rebar_config,rebar_core,rebar_erlc_compiler,
-                        rebar_erlydtl_compiler,rebar_fetch,rebar_file_utils,
-                        rebar_log,rebar_otp_app,rebar_packages,rebar_plugins,
-                        rebar_provider,rebar_prv_app_discovery,
-                        rebar_prv_compile,rebar_prv_deps,rebar_prv_do,
-                        rebar_prv_escripter,rebar_prv_help,
-                        rebar_prv_install_deps,rebar_prv_lock,rebar_prv_new,
-                        rebar_prv_packages,rebar_prv_release,rebar_prv_shell,
-                        rebar_prv_tar,rebar_prv_update,rebar_prv_version,
-                        rebar_state,rebar_templater,rebar_topo,rebar_utils,
-                        'relx.config_dtl','sup.erl_dtl','sys.config_dtl',
-                        'vm.args_dtl']},
-              {registered,[]},
-              {applications,[kernel,stdlib,sasl,compiler,crypto,syntax_tools,
-                             tools,erlware_commons,relx,inets]},
-              {env,[{log_level,warn},
-                    {providers,[rebar_prv_escripter,rebar_prv_deps,
-                                rebar_prv_do,rebar_prv_lock,
-                                rebar_prv_install_deps,rebar_prv_packages,
-                                rebar_erlydtl_compiler,rebar_prv_compile,
-                                rebar_prv_app_discovery,rebar_prv_shell,
-                                rebar_prv_tar,rebar_prv_new,rebar_prv_update,
-                                rebar_prv_release,rebar_prv_version,
-                                rebar_prv_help]}]}]}.
diff --git a/include/rebar.hrl b/include/rebar.hrl
index 1b83a9b..bae974d 100644
--- a/include/rebar.hrl
+++ b/include/rebar.hrl
@@ -13,16 +13,14 @@
 
 -define(FMT(Str, Args), lists:flatten(io_lib:format(Str, Args))).
 
--record(provider,  {name :: atom(),            % The 'user friendly' name of the task
-                    provider_impl :: atom(),   % The implementation of the task, maybe fun or
-                    bare :: boolean(),         % Indicates whether a build config is needed
-                    deps :: [atom()],          % The list of dependencies
-                    desc :: string(),          % The description for the task
-                    short_desc :: string(),    % A one line short description of the task
-                    example :: string(),       % An example of the task usage
-                    opts :: list()}).          % The list of options that the task requires/understands
-
--define(DEFAULT_LIB_DIRS, ["apps", "libs", "."]).
--define(DEFAULT_DEPS_DIRS, ["deps"]).
+-define(DEFAULT_LIB_DIRS, ["_checkouts", "apps", "libs", "."]).
+-define(DEFAULT_DEPS_DIR, "_deps").
+-define(DEFAULT_PLUGINS_DIR, "_plugins").
 -define(DEFAULT_CONFIG_FILE, "rebar.config").
 -define(LOCK_FILE, "rebar.lock").
+
+-ifdef(namespaced_types).
+-type rebar_dict() :: dict:dict().
+-else.
+-type rebar_dict() :: dict().
+-endif.
diff --git a/priv/templates/gitignore.dtl b/priv/templates/gitignore.dtl
index 79ae0fb..23123d4 100644
--- a/priv/templates/gitignore.dtl
+++ b/priv/templates/gitignore.dtl
@@ -1,6 +1,6 @@
+_*
 .eunit
 deps
-priv
 *.o
 *.beam
 *.plt
diff --git a/priv/templates/otp_app.template b/priv/templates/otp_app.template
new file mode 100644
index 0000000..db31b31
--- /dev/null
+++ b/priv/templates/otp_app.template
@@ -0,0 +1,7 @@
+{variables, []}.
+{template, "app.erl", "src/{{appid}}_app.erl"}.
+{template, "otp_app.app.src", "src/{{appid}}.app.src"}.
+{template, "rebar.config", "rebar.config"}.
+{template, "gitignore", ".gitignore"}.
+{template, "LICENSE", "LICENSE"}.
+{template, "README.md", "README.md"}.
diff --git a/priv/templates/otp_lib.template.dtl b/priv/templates/otp_lib.template
index 19d7593..19d7593 100644
--- a/priv/templates/otp_lib.template.dtl
+++ b/priv/templates/otp_lib.template
diff --git a/priv/templates/plugin.erl.dtl b/priv/templates/plugin.erl.dtl
new file mode 100644
index 0000000..80a03bb
--- /dev/null
+++ b/priv/templates/plugin.erl.dtl
@@ -0,0 +1,29 @@
+-module({{appid}}).
+
+-behaviour(rebar_provider).
+
+-export([init/1,
+         do/1]).
+
+-define(PROVIDER, {{appid}}).
+-define(DEPS, []).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
+init(State) ->
+    State1 = rebar_state:add_provider(State, rebar_provider:create([{name, ?PROVIDER},
+                                                                    {provider_impl, ?MODULE},
+                                                                    {bare, false},
+                                                                    {deps, ?DEPS},
+                                                                    {example, "rebar {{appid}}"},
+                                                                    {short_desc, "{{appid}} plugin."},
+                                                                    {desc, ""},
+                                                                    {opts, []}])),
+    {ok, State1}.
+
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+do(State) ->
+    {ok, State}.
diff --git a/priv/templates/plugin.template b/priv/templates/plugin.template
new file mode 100644
index 0000000..bc44863
--- /dev/null
+++ b/priv/templates/plugin.template
@@ -0,0 +1,7 @@
+{variables, []}.
+{template, "plugin.erl", "src/{{appid}}.erl"}.
+{template, "otp_lib.app.src", "src/{{appid}}.app.src"}.
+{template, "rebar.config", "rebar.config"}.
+{template, "gitignore", ".gitignore"}.
+{template, "LICENSE", "LICENSE"}.
+{template, "plugin_README.md", "README.md"}.
diff --git a/priv/templates/plugin_README.md.dtl b/priv/templates/plugin_README.md.dtl
new file mode 100644
index 0000000..19990f5
--- /dev/null
+++ b/priv/templates/plugin_README.md.dtl
@@ -0,0 +1,14 @@
+{{appid}}
+=====
+
+Rebar3 plugin
+
+Build
+-----
+
+    $ rebar3 compile
+
+Use
+---
+
+    $ rebar3 {{appid}}
diff --git a/rebar.config b/rebar.config
index e465df1..0014c3a 100644
--- a/rebar.config
+++ b/rebar.config
@@ -5,12 +5,19 @@
 
 %% escript_incl_extra is for internal rebar-private use only.
 %% Do not use outside rebar. Config interface is not stable.
-{escript_incl_extra, [{"priv/templates/*", "."}]}.
+{escript_incl_extra, [{"priv/templates/*", "."}, {"rebar/include/*", "."}]}.
+
 {escript_incl_apps,
- [inets, getopt, erlydtl, erlware_commons, relx]}.
+ [inets, getopt, erlydtl, erlware_commons, relx,  providers, rebar]}.
 {escript_top_level_app, rebar}.
 {escript_name, rebar3}.
 
+{erl_opts,
+ [{platform_define, "^[0-9]+", namespaced_types},
+  {platform_define, "^R1[4|5]", deprecated_crypto},
+  debug_info,
+  warnings_as_errors]}.
+
 %% Types dict:dict() and digraph:digraph() have been introduced in Erlang 17.
 %% At the same time, their counterparts dict() and digraph() are to be
 %% deprecated in Erlang 18. namespaced_types option is used to select proper
@@ -20,27 +27,13 @@
   {platform_define, "^[0-9]+", namespaced_types}
  ]}.
 
-{xref_checks, []}.
-{xref_queries,
- [{"(XC - UC) || (XU - X - B
-      - (\"escript\":\"foldl\"/\"3\")
-      - (\"eunit_test\":\"function_wrapper\"/\"2\")
-      - (\"abnfc\":\"file\"/\"2\")
-      - (\"erlydtl\":\"compile\"/\"3\")
-      - (\"lfe_comp\":\"file\"/\"2\")
-      - (\"neotoma\":\"file\"/\"2\")
-      - (\"protobuffs_compile\":\"scan_file\"/\"2\")
-      - (\"diameter_codegen\":\"from_dict\"/\"4\")
-      - (\"diameter_dict_util\":\"format_error\"/\"1\")
-      - (\"diameter_dict_util\":\"parse\"/\"2\"))",
-         []}]}.
-
-{first_files, [rebar_provider]}.
-
-{deps, [{relx, "",
-         {git, "https://github.com/erlware/relx.git",
-          {branch, "master"}}},
-       {getopt, "", {git, "git@github.com:jcomellas/getopt.git", {branch, "master"}}}]}.
+{deps, [{providers, "",
+         {git, "https://github.com/tsloughter/providers.git",
+          {branch, "format_error"}}},
+        {relx, "",
+         {git, "https://github.com/tsloughter/relx.git",
+          {branch, "format_error2"}}},
+        {getopt, "", {git, "https://github.com/jcomellas/getopt.git", {branch, "master"}}}]}.
 
 {erlydtl_opts, [{doc_root, "priv/templates"},
                 {compiler_options, [report, return, debug_info]}]}.
diff --git a/src/rebar.app.src b/src/rebar.app.src
index 3164b73..c41ad92 100644
--- a/src/rebar.app.src
+++ b/src/rebar.app.src
@@ -21,22 +21,24 @@
         {log_level, warn},
 
         %% any_dir processing modules
-        {providers, [rebar_prv_escripter,
+        {providers, [rebar_prv_clean,
                      rebar_prv_deps,
                      rebar_prv_do,
                      rebar_prv_lock,
                      rebar_prv_install_deps,
                      rebar_prv_packages,
-                     rebar_erlydtl_compiler,
+                     rebar_prv_erlydtl_compiler,
                      rebar_prv_compile,
                      rebar_prv_app_discovery,
                      rebar_prv_shell,
                      rebar_prv_tar,
                      rebar_prv_new,
                      rebar_prv_update,
+                     rebar_prv_upgrade,
                      rebar_prv_release,
                      rebar_prv_version,
                      rebar_prv_common_test,
-                     rebar_prv_help]}
+                     rebar_prv_help,
+                     rebar_prv_test_deps]}
         ]}
  ]}.
diff --git a/src/rebar3.erl b/src/rebar3.erl
index dcd78f7..22c08ca 100644
--- a/src/rebar3.erl
+++ b/src/rebar3.erl
@@ -28,15 +28,16 @@
 
 -export([main/1,
          run/2,
-         option_spec_list/0,
+         global_option_spec_list/0,
+         init_config/0,
+         init_config1/1,
+         set_options/2,
          parse_args/1,
          version/0,
-         log_level/1]).
+         log_level/0]).
 
 -include("rebar.hrl").
 
--define(DEFAULT_JOBS, 3).
-
 %% ====================================================================
 %% Public API
 %% ====================================================================
@@ -44,14 +45,21 @@
 %% escript Entry point
 main(Args) ->
     case catch(run(Args)) of
-        ok ->
+        {ok, _State} ->
             ok;
         rebar_abort ->
             rebar_utils:delayed_halt(1);
+        {error, {Module, Reason}} ->
+            ?ERROR(Module:format_error(Reason, []), []),
+            rebar_utils:delayed_halt(1);
+        {error, Error} ->
+            ?ERROR(Error++"~n", []),
+            rebar_utils:delayed_halt(1);
         Error ->
             %% Nothing should percolate up from rebar_core;
             %% Dump this error to console
-            io:format("Uncaught error in rebar_core: ~p\n", [Error]),
+            ?ERROR("Uncaught error in rebar_core. Run with DEBUG=1 to see stacktrace~n", []),
+            ?DEBUG("Uncaught error: ~p~n", [Error]),
             rebar_utils:delayed_halt(1)
     end.
 
@@ -59,7 +67,7 @@ main(Args) ->
 run(BaseState, Command) ->
     _ = application:load(rebar),
     BaseState1 = rebar_state:set(BaseState, task, Command),
-    run_aux(BaseState1, []).
+    run_aux(BaseState1, [Command]).
 
 %% ====================================================================
 %% Internal functions
@@ -67,24 +75,21 @@ run(BaseState, Command) ->
 
 run(RawArgs) ->
     ok = load_rebar_app(),
-    %% Parse out command line arguments -- what's left is a list of commands to
-    %% run -- and start running commands
-    Args = parse_args(RawArgs),
-    BaseConfig = init_config(Args),
-    {BaseConfig1, Args1} = set_options(BaseConfig, Args),
-    run_aux(BaseConfig1, Args1).
+    BaseConfig = init_config(),
+    {BaseConfig1, _Args1} = set_options(BaseConfig, {[], []}),
+    run_aux(BaseConfig1, RawArgs).
 
 load_rebar_app() ->
     %% Pre-load the rebar app so that we get default configuration
     ok = application:load(rebar).
 
-init_config({Options, _NonOptArgs}) ->
+init_config() ->
     %% Initialize logging system
-    Verbosity = log_level(Options),
+    Verbosity = log_level(),
     ok = rebar_log:init(command_line, Verbosity),
 
-    Config = case proplists:get_value(config, Options) of
-                 undefined ->
+    Config = case os:getenv("REBAR_CONFIG") of
+                 false ->
                      rebar_config:consult_file(?DEFAULT_CONFIG_FILE);
                  ConfigFile ->
                      rebar_config:consult_file(ConfigFile)
@@ -103,8 +108,8 @@ init_config({Options, _NonOptArgs}) ->
                 true ->
                     ?DEBUG("Load global config file ~p~n",
                            [GlobalConfigFile]),
-                    rebar_config:consult_file(GlobalConfigFile),
-                    rebar_state:new(GlobalConfigFile, Config1);
+                    GlobalConfig = rebar_state:new(rebar_config:consult_file(GlobalConfigFile)),
+                    rebar_state:new(GlobalConfig, Config1);
                 false ->
                     rebar_state:new(Config1)
             end,
@@ -123,7 +128,7 @@ init_config1(BaseConfig) ->
             BaseConfig
     end.
 
-run_aux(State, Args) ->
+run_aux(State, RawArgs) ->
     %% Make sure crypto is running
     case crypto:start() of
         ok -> ok;
@@ -136,28 +141,33 @@ run_aux(State, Args) ->
 
     State1 = init_config1(State),
 
+    code:add_pathsa([filename:join(rebar_utils:get_cwd(), "plugins")]),
     %% Process each command, resetting any state between each one
     State2 = rebar_state:set(State1, base_dir, filename:absname(rebar_state:dir(State1))),
     {ok, Providers} = application:get_env(rebar, providers),
-    State3 = rebar_state:create_logic_providers(Providers, State2),
-    Task = rebar_state:get(State3, task, "help"),
-    rebar_core:process_command(rebar_state:command_args(State3, Args), list_to_atom(Task)),
-    ok.
+
+    {ok, PluginProviders, State3} = rebar_plugins:install(State2),
+    rebar_core:update_code_path(State3),
+
+    State4 = rebar_state:create_logic_providers(Providers++PluginProviders, State3),
+    {Task, Args} = parse_args(RawArgs),
+
+    rebar_core:process_command(rebar_state:command_args(State4, Args), list_to_atom(Task)).
 
 %%
 %% Parse command line arguments using getopt and also filtering out any
 %% key=value pairs. What's left is the list of commands to run
 %%
-parse_args(RawArgs) ->
-    %% Parse getopt options
-    OptSpecList = option_spec_list(),
-    case getopt:parse(OptSpecList, RawArgs) of
-        {ok, Args} ->
-            Args;
-        {error, {Reason, Data}} ->
-            ?ERROR("~s ~p~n~n", [Reason, Data]),
-            rebar_utils:delayed_halt(1)
-    end.
+parse_args([]) ->
+    parse_args(["help"]);
+parse_args([H | Rest]) when H =:= "-h"
+                          ; H =:= "--help" ->
+    parse_args(["help" | Rest]);
+parse_args([H | Rest]) when H =:= "-v"
+                          ; H =:= "--version" ->
+    parse_args(["version" | Rest]);
+parse_args([RawTask | RawRest]) ->
+    {RawTask, RawRest}.
 
 set_options(State, {Options, NonOptArgs}) ->
     GlobalDefines = proplists:get_all_values(defines, Options),
@@ -166,32 +176,26 @@ set_options(State, {Options, NonOptArgs}) ->
 
     %% Set global variables based on getopt options
     State2 = set_global_flag(State1, Options, force),
-    State3 = case proplists:get_value(jobs, Options, ?DEFAULT_JOBS) of
-                 ?DEFAULT_JOBS ->
-                     State2;
-                 Jobs ->
-                     rebar_state:set(State2, jobs, Jobs)
-             end,
 
     Task = proplists:get_value(task, Options, "help"),
 
-    {rebar_state:set(State3, task, Task), NonOptArgs}.
+    {rebar_state:set(State2, task, Task), NonOptArgs}.
 
 %%
 %% get log level based on getopt option
 %%
-log_level(Options) ->
-    case proplists:get_bool(quiet, Options) of
-        true ->
-            rebar_log:error_level();
+log_level() ->
+    case os:getenv("QUIET") of
         false ->
             DefaultLevel = rebar_log:default_level(),
-            case proplists:get_all_values(verbose, Options) of
-                [] ->
+            case os:getenv("DEBUG") of
+                false ->
                     DefaultLevel;
-                Verbosities ->
-                    DefaultLevel + lists:last(Verbosities)
-            end
+                _ ->
+                    DefaultLevel + 3
+            end;
+         _ ->
+            rebar_log:error_level()
     end.
 
 %%
@@ -218,17 +222,12 @@ set_global_flag(State, Options, Flag) ->
 %%
 %% options accepted via getopt
 %%
-option_spec_list() ->
-    Jobs = ?DEFAULT_JOBS,
-    JobsHelp = io_lib:format(
-                 "Number of concurrent workers a command may use. Default: ~B",
-                 [Jobs]),
+global_option_spec_list() ->
     [
-     %% {Name, ShortOpt, LongOpt, ArgSpec, HelpMsg}
-     {help,     $h, "help",     undefined, "Print this help."},
-     {verbose,  $v, "verbose",  integer,   "Verbosity level (-v, -vv)."},
-     {version,  $V, "version",  undefined, "Show version information."},
-     {jobs,     $j, "jobs",     integer,   JobsHelp},
-     {config,   $C, "config",   string,    "Rebar config file to use."},
-     {task,     undefined, undefined, string, "Task to run."}
+    %% {Name, ShortOpt, LongOpt, ArgSpec, HelpMsg}
+    {help,     $h, "help",     undefined, "Print this help."},
+    %{verbose,  $v, "verbose",  integer,   "Verbosity level (-v, -vv)."},
+    {version,  $V, "version",  undefined, "Show version information."},
+    %{config,   $C, "config",   string,    "Rebar config file to use."},
+    {task,     undefined, undefined, string, "Task to run."}
     ].
diff --git a/src/rebar_app_discover.erl b/src/rebar_app_discover.erl
index c90a8df..ae4916e 100644
--- a/src/rebar_app_discover.erl
+++ b/src/rebar_app_discover.erl
@@ -13,7 +13,8 @@ do(State, LibDirs) ->
     Apps = find_apps(Dirs, all),
     ProjectDeps = rebar_state:deps_names(State),
     lists:foldl(fun(AppInfo, StateAcc) ->
-                        rebar_state:project_apps(StateAcc, rebar_app_info:deps(AppInfo, ProjectDeps))
+                        ProjectDeps1 = lists:delete(rebar_app_info:name(AppInfo), ProjectDeps),
+                        rebar_state:project_apps(StateAcc, rebar_app_info:deps(AppInfo, ProjectDeps1))
             end, State, Apps).
 
 -spec all_app_dirs(list(file:name())) -> list(file:name()).
@@ -47,14 +48,17 @@ app_dirs(LibDir) ->
 find_unbuilt_apps(LibDirs) ->
     find_apps(LibDirs, invalid).
 
+-spec find_apps([file:filename_all()]) -> [rebar_app_info:t()].
 find_apps(LibDirs) ->
     find_apps(LibDirs, valid).
 
+-spec find_apps([file:filename_all()], valid | invalid | all) -> [rebar_app_info:t()].
 find_apps(LibDirs, Validate) ->
     rebar_utils:filtermap(fun(AppDir) ->
                                   find_app(AppDir, Validate)
                           end, all_app_dirs(LibDirs)).
 
+-spec find_app(file:filename_all(), valid | invalid | all) -> {true, rebar_app_info:t()} | false.
 find_app(AppDir, Validate) ->
     AppFile = filelib:wildcard(filename:join([AppDir, "ebin", "*.app"])),
     AppSrcFile = filelib:wildcard(filename:join([AppDir, "src", "*.app.src"])),
@@ -104,12 +108,17 @@ find_app(AppDir, Validate) ->
 app_dir(AppFile) ->
     filename:join(rebar_utils:droplast(filename:split(filename:dirname(AppFile)))).
 
+-spec create_app_info(file:name(), file:name()) -> rebar_app_info:t() | error.
 create_app_info(AppDir, AppFile) ->
     case file:consult(AppFile) of
         {ok, [{application, AppName, AppDetails}]} ->
             AppVsn = proplists:get_value(vsn, AppDetails),
+            %AppDeps = proplists:get_value(applications, AppDetails, []),
+            C = rebar_config:consult(AppDir),
+            S = rebar_state:new(rebar_state:new(), C, AppDir),
+            AppDeps = rebar_state:deps_names(S),
             AbsCwd = filename:absname(rebar_utils:get_cwd()),
-            {ok, AppInfo} = rebar_app_info:new(AppName, AppVsn, AppDir),
+            {ok, AppInfo} = rebar_app_info:new(AppName, AppVsn, AppDir, AppDeps),
             RebarConfig = filename:join(AppDir, "rebar.config"),
             AppState = case filelib:is_file(RebarConfig) of
                             true ->
@@ -121,22 +130,28 @@ create_app_info(AppDir, AppFile) ->
             AppState1 = rebar_state:set(AppState, base_dir, AbsCwd),
             AppInfo1 = rebar_app_info:config(
                          rebar_app_info:app_details(AppInfo, AppDetails), AppState1),
-            rebar_app_info:dir(AppInfo1, AppDir)
+            rebar_app_info:dir(AppInfo1, AppDir);
+        _ ->
+            error
     end.
 
 -spec validate_application_info(rebar_app_info:t()) -> boolean().
 validate_application_info(AppInfo) ->
     EbinDir = rebar_app_info:ebin_dir(AppInfo),
-    AppFile = rebar_app_info:app_file(AppInfo),
-    AppDetail = rebar_app_info:app_details(AppInfo),
-    case get_modules_list(AppFile, AppDetail) of
-        {ok, List} ->
-            has_all_beams(EbinDir, List);
-        _Error ->
-            false
+    case rebar_app_info:app_file(AppInfo) of
+        undefined ->
+            false;
+        AppFile ->
+            AppDetail = rebar_app_info:app_details(AppInfo),
+            case get_modules_list(AppFile, AppDetail) of
+                {ok, List} ->
+                    has_all_beams(EbinDir, List);
+                _Error ->
+                    false
+            end
     end.
 
--spec get_modules_list(file:name(), proplists:proplist()) ->
+-spec get_modules_list(file:filename_all(), proplists:proplist()) ->
                               {ok, list()} |
                               {warning, Reason::term()} |
                               {error, Reason::term()}.
@@ -148,8 +163,7 @@ get_modules_list(AppFile, AppDetail) ->
             {ok, ModulesList}
     end.
 
--spec has_all_beams(file:name(), list()) ->
-                           ok | {error, Reason::term()}.
+-spec has_all_beams(file:filename_all(), list()) -> boolean().
 has_all_beams(EbinDir, [Module | ModuleList]) ->
     BeamFile = filename:join([EbinDir,
                               ec_cnv:to_list(Module) ++ ".beam"]),
diff --git a/src/rebar_app_info.erl b/src/rebar_app_info.erl
index 008bfd2..7a33811 100644
--- a/src/rebar_app_info.erl
+++ b/src/rebar_app_info.erl
@@ -1,7 +1,6 @@
 -module(rebar_app_info).
 
--export([new/0,
-         new/1,
+-export([new/1,
          new/2,
          new/3,
          new/4,
@@ -21,6 +20,8 @@
          ebin_dir/1,
          deps/1,
          deps/2,
+         dep_level/1,
+         dep_level/2,
          dir/1,
          dir/2,
          source/1,
@@ -31,43 +32,40 @@
 -export_type([t/0]).
 
 -record(app_info_t, {name :: binary(),
-                     app_file_src :: file:name() | undefined,
-                     app_file :: file:name(),
-                     config :: rebar_config:config() | undefined,
-                     original_vsn :: string(),
+                     app_file_src :: file:filename_all() | undefined,
+                     app_file :: file:filename_all() | undefined,
+                     config :: rebar_state:t() | undefined,
+                     original_vsn :: binary() | string() | undefined,
                      app_details=[] :: list(),
                      deps=[] :: list(),
+                     dep_level :: integer(),
                      dir :: file:name(),
-                     source :: string() | undefined,
+                     source :: string() | tuple() | undefined,
                      valid :: boolean()}).
 
 %%============================================================================
 %% types
 %%============================================================================
--opaque t() :: record(app_info_t).
+-type t() :: record(app_info_t).
 
 %%============================================================================
 %% API
 %% ============================================================================
 %% @doc Build a new, empty, app info value. This is not of a lot of use and you
 %% probably wont be doing this much.
--spec new() -> {ok, t()}.
-new() ->
-    {ok, #app_info_t{}}.
-
 -spec new(atom() | binary() | string()) ->
                  {ok, t()}.
 new(AppName) ->
     {ok, #app_info_t{name=ec_cnv:to_binary(AppName)}}.
 
--spec new(atom() | binary() | string(), string()) ->
+-spec new(atom() | binary() | string(), binary() | string()) ->
                  {ok, t()}.
 new(AppName, Vsn) ->
     {ok, #app_info_t{name=ec_cnv:to_binary(AppName),
                      original_vsn=Vsn}}.
 
 %% @doc build a complete version of the app info with all fields set.
--spec new(atom() | binary() | string(), string(), file:name()) ->
+-spec new(atom() | binary() | string(), binary() | string(), file:name()) ->
                  {ok, t()}.
 new(AppName, Vsn, Dir) ->
     {ok, #app_info_t{name=ec_cnv:to_binary(AppName),
@@ -75,7 +73,7 @@ new(AppName, Vsn, Dir) ->
                      dir=Dir}}.
 
 %% @doc build a complete version of the app info with all fields set.
--spec new(atom() | binary() | string(), string(), file:name(), list()) ->
+-spec new(atom() | binary() | string(), binary() | string(), file:name(), list()) ->
                  {ok, t()}.
 new(AppName, Vsn, Dir, Deps) ->
     {ok, #app_info_t{name=ec_cnv:to_binary(AppName),
@@ -84,17 +82,16 @@ new(AppName, Vsn, Dir, Deps) ->
                      deps=Deps}}.
 
 %% @doc discover a complete version of the app info with all fields set.
--spec discover(file:name()) ->
-                 {ok, t()}.
+-spec discover(file:filename_all()) -> {ok, t()} | not_found.
 discover(Dir) ->
     case rebar_app_discover:find_app(Dir, all) of
         {true, AppInfo} ->
             {ok, AppInfo};
-        _ ->
+        false ->
             not_found
     end.
 
--spec name(t()) -> atom().
+-spec name(t()) -> binary().
 name(#app_info_t{name=Name}) ->
     Name.
 
@@ -102,15 +99,15 @@ name(#app_info_t{name=Name}) ->
 name(AppInfo=#app_info_t{}, AppName) ->
     AppInfo#app_info_t{name=ec_cnv:to_binary(AppName)}.
 
--spec config(t()) -> rebar_config:confg().
+-spec config(t()) -> rebar_state:t().
 config(#app_info_t{config=Config}) ->
     Config.
 
--spec config(t(), rebar_config:confg()) -> t().
+-spec config(t(), rebar_state:t()) -> t().
 config(AppInfo=#app_info_t{}, Config) ->
     AppInfo#app_info_t{config=Config}.
 
--spec app_file_src(t()) -> file:name().
+-spec app_file_src(t()) -> file:filename_all() | undefined.
 app_file_src(#app_info_t{app_file_src=undefined, dir=Dir, name=Name}) ->
     AppFileSrc = filename:join([ec_cnv:to_list(Dir), "src", ec_cnv:to_list(Name)++".app.src"]),
     case filelib:is_file(AppFileSrc) of
@@ -122,11 +119,11 @@ app_file_src(#app_info_t{app_file_src=undefined, dir=Dir, name=Name}) ->
 app_file_src(#app_info_t{app_file_src=AppFileSrc}) ->
     ec_cnv:to_list(AppFileSrc).
 
--spec app_file_src(t(), file:name()) -> t().
+-spec app_file_src(t(), file:filename_all()) -> t().
 app_file_src(AppInfo=#app_info_t{}, AppFileSrc) ->
     AppInfo#app_info_t{app_file_src=ec_cnv:to_list(AppFileSrc)}.
 
--spec app_file(t()) -> file:name().
+-spec app_file(t()) -> file:filename_all() | undefined.
 app_file(#app_info_t{app_file=undefined, dir=Dir, name=Name}) ->
     AppFile = filename:join([ec_cnv:to_list(Dir), "ebin", ec_cnv:to_list(Name)++".app"]),
     case filelib:is_file(AppFile) of
@@ -138,9 +135,9 @@ app_file(#app_info_t{app_file=undefined, dir=Dir, name=Name}) ->
 app_file(#app_info_t{app_file=AppFile}) ->
     AppFile.
 
--spec app_file(t(), file:name()) -> t().
+-spec app_file(t(), file:filename_all()) -> t().
 app_file(AppInfo=#app_info_t{}, AppFile) ->
-    AppInfo#app_info_t{app_file=ec_cnv:to_list(AppFile)}.
+    AppInfo#app_info_t{app_file=AppFile}.
 
 -spec app_details(t()) -> list().
 app_details(#app_info_t{app_details=AppDetails}) ->
@@ -154,7 +151,7 @@ app_details(AppInfo=#app_info_t{}, AppDetails) ->
 original_vsn(#app_info_t{original_vsn=Vsn}) ->
     Vsn.
 
--spec original_vsn(t(), string()) -> string().
+-spec original_vsn(t(), string()) -> t().
 original_vsn(AppInfo=#app_info_t{}, Vsn) ->
     AppInfo#app_info_t{original_vsn=Vsn}.
 
@@ -166,6 +163,12 @@ deps(#app_info_t{deps=Deps}) ->
 deps(AppInfo=#app_info_t{}, Deps) ->
     AppInfo#app_info_t{deps=Deps}.
 
+dep_level(AppInfo=#app_info_t{}, Level) ->
+    AppInfo#app_info_t{dep_level=Level}.
+
+dep_level(#app_info_t{dep_level=Level}) ->
+    Level.
+
 -spec dir(t()) -> file:name().
 dir(#app_info_t{dir=Dir}) ->
     Dir.
@@ -178,11 +181,11 @@ dir(AppInfo=#app_info_t{}, Dir) ->
 ebin_dir(#app_info_t{dir=Dir}) ->
     filename:join(Dir, "ebin").
 
--spec source(t(), string()) -> t().
+-spec source(t(), string() | tuple()) -> t().
 source(AppInfo=#app_info_t{}, Source) ->
     AppInfo#app_info_t{source=Source}.
 
--spec source(t()) -> string().
+-spec source(t()) -> string() | tuple().
 source(#app_info_t{source=Source}) ->
     Source.
 
diff --git a/src/rebar_app_utils.erl b/src/rebar_app_utils.erl
index 1c53743..8fc3df8 100644
--- a/src/rebar_app_utils.erl
+++ b/src/rebar_app_utils.erl
@@ -26,13 +26,14 @@
 %% -------------------------------------------------------------------
 -module(rebar_app_utils).
 
--export([is_app_dir/0, is_app_dir/1,
+-export([find/2,
+         find/3,
+         is_app_dir/0, is_app_dir/1,
          is_app_src/1,
          app_src_to_app/1,
          app_name/2,
          app_applications/2,
-         app_vsn/2,
-         is_skipped_app/2]).
+         app_vsn/2]).
 
 -export([load_app_file/2]). % TEMPORARY
 
@@ -42,9 +43,22 @@
 %% Public API
 %% ===================================================================
 
+-spec find(binary(), [rebar_app_info:t()]) -> {ok, rebar_app_info:t()} | error.
+find(Name, Apps) ->
+    ec_lists:find(fun(App) -> rebar_app_info:name(App) =:= Name end, Apps).
+
+-spec find(binary(), binary(), [rebar_app_info:t()]) -> {ok, rebar_app_info:t()} | error.
+find(Name, Vsn, Apps) ->
+    ec_lists:find(fun(App) ->
+                          rebar_app_info:name(App) =:= Name
+                              andalso rebar_app_info:original_vsn(App) =:= Vsn
+                  end, Apps).
+
+-spec is_app_dir() -> {true, file:name()} | false.
 is_app_dir() ->
     is_app_dir(rebar_utils:get_cwd()).
 
+-spec is_app_dir(file:name()) -> {true, file:name()} | false.
 is_app_dir(Dir) ->
     SrcDir = filename:join([Dir, "src"]),
     AppSrc = filename:join([SrcDir, "*.app.src"]),
@@ -109,30 +123,6 @@ app_vsn(Config, AppFile) ->
                    [AppFile, Reason])
     end.
 
-is_skipped_app(Config, AppFile) ->
-    {Config1, ThisApp} = app_name(Config, AppFile),
-    %% Check for apps global parameter; this is a comma-delimited list
-    %% of apps on which we want to run commands
-    Skipped =
-        case get_apps(Config) of
-            undefined ->
-                %% No apps parameter specified, check the skip_apps list..
-                case get_skip_apps(Config) of
-                    undefined ->
-                        %% No skip_apps list, run everything..
-                        false;
-                    SkipApps ->
-                        TargetApps = [list_to_atom(A) ||
-                                         A <- string:tokens(SkipApps, ",")],
-                        is_skipped(ThisApp, TargetApps)
-                end;
-            Apps ->
-                %% run only selected apps
-                TargetApps = [list_to_atom(A) || A <- string:tokens(Apps, ",")],
-                is_selected(ThisApp, TargetApps)
-        end,
-    {Config1, Skipped}.
-
 %% ===================================================================
 %% Internal functions
 %% ===================================================================
@@ -176,27 +166,3 @@ get_value(Key, AppInfo, AppFile) ->
         Value ->
             Value
     end.
-
-%% apps= for selecting apps
-is_selected(ThisApp, TargetApps) ->
-    case lists:member(ThisApp, TargetApps) of
-        false ->
-            {true, ThisApp};
-        true ->
-            false
-    end.
-
-%% skip_apps= for filtering apps
-is_skipped(ThisApp, TargetApps) ->
-    case lists:member(ThisApp, TargetApps) of
-        false ->
-            false;
-        true ->
-            {true, ThisApp}
-    end.
-
-get_apps(Config) ->
-    rebar_config:get_global(Config, apps, undefined).
-
-get_skip_apps(Config) ->
-    rebar_config:get_global(Config, skip_apps, undefined).
diff --git a/src/rebar_config.erl b/src/rebar_config.erl
index a45bef9..7ef2488 100644
--- a/src/rebar_config.erl
+++ b/src/rebar_config.erl
@@ -35,11 +35,11 @@
 %% Public API
 %% ===================================================================
 
--spec consult(file:name()) -> {ok, any()}.
+-spec consult(file:name()) -> [any()].
 consult(Dir) ->
     consult_file(filename:join(Dir, ?DEFAULT_CONFIG_FILE)).
 
--spec consult_file(file:name()) -> {ok, any()}.
+-spec consult_file(file:name()) -> [any()].
 consult_file(File) when is_binary(File) ->
     consult_file(binary_to_list(File));
 consult_file(File) ->
@@ -73,7 +73,6 @@ remove_script_ext(F) ->
 try_consult(File) ->
     case file:consult(File) of
         {ok, Terms} ->
-            ?DEBUG("Consult config file ~p~n", [File]),
             Terms;
         {error, enoent} ->
             [];
diff --git a/src/rebar_core.erl b/src/rebar_core.erl
index cb021e3..16d8f07 100644
--- a/src/rebar_core.erl
+++ b/src/rebar_core.erl
@@ -26,33 +26,61 @@
 %% -------------------------------------------------------------------
 -module(rebar_core).
 
--export([process_command/2]).
+-export([process_command/2
+        ,update_code_path/1]).
 
 -include("rebar.hrl").
 
+-spec process_command(rebar_state:t(), atom()) -> {ok, rebar_state:t()} | {error, string()}.
 process_command(State, Command) ->
+    %% ? rebar_prv_install_deps:setup_env(State),
+    Providers = rebar_state:providers(State),
+    TargetProviders = providers:get_target_providers(Command, Providers),
+    case providers:get_provider(Command, Providers) of
+        not_found ->
+            {error, io_lib:format("Command ~p not found", [Command])};
+        CommandProvider ->
+            Opts = providers:opts(CommandProvider)++rebar3:global_option_spec_list(),
+            case Command of
+                do ->
+                    do(TargetProviders, State);
+                _ ->
+                    case getopt:parse(Opts, rebar_state:command_args(State)) of
+                        {ok, Args} ->
+                            State2 = rebar_state:command_parsed_args(State, Args),
+                            do(TargetProviders, State2);
+                        {error, {invalid_option, Option}} ->
+                            {error, io_lib:format("Invalid option ~s on task ~p", [Option, Command])}
+                    end
+            end
+    end.
+
+-spec do([atom()], rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do([], State) ->
+    {ok, State};
+do([ProviderName | Rest], State) ->
+    Provider = providers:get_provider(ProviderName
+                                     ,rebar_state:providers(State)),
+    case providers:do(Provider, State) of
+        {ok, State1} ->
+            do(Rest, State1);
+        {error, Error} ->
+            {error, Error}
+    end.
+
+update_code_path(State) ->
     true = rebar_utils:expand_code_path(),
     LibDirs = rebar_state:get(State, lib_dirs, ?DEFAULT_LIB_DIRS),
-    DepsDir = rebar_state:get(State, deps_dir, ?DEFAULT_DEPS_DIRS),
-    _UpdatedCodePaths = update_code_path([DepsDir | LibDirs]),
-    rebar_prv_install_deps:setup_env(State),
-
-    TargetProviders = rebar_provider:get_target_providers(Command, State),
+    DepsDir = rebar_state:get(State, deps_dir, ?DEFAULT_DEPS_DIR),
+    PluginsDir = rebar_state:get(State, plugins_dir, ?DEFAULT_PLUGINS_DIR),
+    _UpdatedCodePaths = update_code_path_([DepsDir, PluginsDir | LibDirs]).
 
-    lists:foldl(fun(TargetProvider, Conf) ->
-                        Provider = rebar_provider:get_provider(TargetProvider
-                                                              ,rebar_state:providers(Conf)),
-                        {ok, Conf1} = rebar_provider:do(Provider, Conf),
-                        Conf1
-                end, State, TargetProviders).
 
 %% ===================================================================
 %% Internal functions
 %% ===================================================================
 
-update_code_path([]) ->
-    no_change;
-update_code_path(Paths) ->
+update_code_path_(Paths) ->
     LibPaths = expand_lib_dirs(Paths, rebar_utils:get_cwd(), []),
     ok = code:add_pathsa(LibPaths),
     %% track just the paths we added, so we can remove them without
diff --git a/src/rebar_erlc_compiler.erl b/src/rebar_erlc_compiler.erl
index 6a16977..33983e4 100644
--- a/src/rebar_erlc_compiler.erl
+++ b/src/rebar_erlc_compiler.erl
@@ -96,30 +96,30 @@ compile(Config, Dir) ->
     rebar_base_compiler:run(Config,
                             check_files(rebar_state:get(
                                           Config, xrl_first_files, [])),
-                            "src", ".xrl", "src", ".erl",
+                            filename:join(Dir, "src"), ".xrl", filename:join(Dir, "src"), ".erl",
                             fun compile_xrl/3),
     rebar_base_compiler:run(Config,
                             check_files(rebar_state:get(
                                           Config, yrl_first_files, [])),
-                            "src", ".yrl", "src", ".erl",
+                            filename:join(Dir, "src"), ".yrl", filename:join(Dir, "src"), ".erl",
                             fun compile_yrl/3),
     rebar_base_compiler:run(Config,
                             check_files(rebar_state:get(
                                           Config, mib_first_files, [])),
-                            "mibs", ".mib", "priv/mibs", ".bin",
+                            filename:join(Dir, "mibs"), ".mib", filename:join([Dir, "priv", "mibs"]), ".bin",
                             fun compile_mib/3),
     doterl_compile(Config, Dir).
 
 -spec clean(rebar_state:t(), file:filename()) -> 'ok'.
-clean(Config, _AppFile) ->
-    MibFiles = rebar_utils:find_files("mibs", ?RE_PREFIX".*\\.mib\$"),
+clean(Config, AppDir) ->
+    MibFiles = rebar_utils:find_files(filename:join(AppDir, "mibs"), ?RE_PREFIX".*\\.mib\$"),
     MIBs = [filename:rootname(filename:basename(MIB)) || MIB <- MibFiles],
     rebar_file_utils:delete_each(
-      [filename:join(["include",MIB++".hrl"]) || MIB <- MIBs]),
+      [filename:join([AppDir, "include",MIB++".hrl"]) || MIB <- MIBs]),
     lists:foreach(fun(F) -> ok = rebar_file_utils:rm_rf(F) end,
-                  ["ebin/*.beam", "priv/mibs/*.bin"]),
+                  [filename:join(AppDir, "ebin/*.beam"), filename:join(AppDir, "priv/mibs/*.bin")]),
 
-    YrlFiles = rebar_utils:find_files("src", ?RE_PREFIX".*\\.[x|y]rl\$"),
+    YrlFiles = rebar_utils:find_files(filename:join(AppDir, "src"), ?RE_PREFIX".*\\.[x|y]rl\$"),
     rebar_file_utils:delete_each(
       [ binary_to_list(iolist_to_binary(re:replace(F, "\\.[x|y]rl$", ".erl")))
         || F <- YrlFiles ]),
@@ -131,9 +131,9 @@ clean(Config, _AppFile) ->
     %% directory structure in ebin with .beam files within. As such, we want
     %% to scan whatever is left in the ebin/ directory for sub-dirs which
     %% satisfy our criteria.
-    BeamFiles = rebar_utils:find_files("ebin", ?RE_PREFIX".*\\.beam\$"),
+    BeamFiles = rebar_utils:find_files(filename:join(AppDir, "ebin"), ?RE_PREFIX".*\\.beam\$"),
     rebar_file_utils:delete_each(BeamFiles),
-    lists:foreach(fun(Dir) -> delete_dir(Dir, dirs(Dir)) end, dirs("ebin")),
+    lists:foreach(fun(Dir) -> delete_dir(Dir, dirs(Dir)) end, dirs(filename:join(AppDir, "ebin"))),
     ok.
 
 %% ===================================================================
@@ -241,14 +241,14 @@ test_compile_config_and_opts(Config, ErlOpts, Cmd) ->
     %% *_first_files is questionable as the file would need to exist
     %% in all project directories for it to work.
     OptsAtom = list_to_atom(Cmd ++ "_compile_opts"),
-    TestOpts = rebar_state:get_list(Config3, OptsAtom, []),
+    TestOpts = rebar_state:get(Config3, OptsAtom, []),
     Opts0 = [{d, 'TEST'}] ++
         ErlOpts ++ TestOpts ++ TriqOpts ++ PropErOpts ++ EqcOpts,
     Opts = [O || O <- Opts0, O =/= no_debug_info],
     Config4 = rebar_state:set(Config3, erl_opts, Opts),
 
     FirstFilesAtom = list_to_atom(Cmd ++ "_first_files"),
-    FirstErls = rebar_state:get_list(Config4, FirstFilesAtom, []),
+    FirstErls = rebar_state:get(Config4, FirstFilesAtom, []),
     Config5 = rebar_state:set(Config4, erl_first_files, FirstErls),
     {Config5, Opts}.
 
@@ -274,7 +274,7 @@ define_if(Def, true) -> [{d, Def}];
 define_if(_Def, false) -> [].
 
 is_lib_avail(Config, DictKey, Mod, Hrl, Name) ->
-    case rebar_state:get_xconf(Config, DictKey, undefined) of
+    case rebar_state:get(Config, DictKey, undefined) of
         undefined ->
             IsAvail = case code:lib_dir(Mod, include) of
                           {error, bad_name} ->
@@ -282,17 +282,17 @@ is_lib_avail(Config, DictKey, Mod, Hrl, Name) ->
                           Dir ->
                               filelib:is_regular(filename:join(Dir, Hrl))
                       end,
-            NewConfig = rebar_state:set_xconf(Config, DictKey, IsAvail),
+            NewConfig = rebar_state:set(Config, DictKey, IsAvail),
             ?DEBUG("~s availability: ~p\n", [Name, IsAvail]),
             {NewConfig, IsAvail};
         IsAvail ->
             {Config, IsAvail}
     end.
 
--spec doterl_compile(rebar_state:t(), file:filename()) -> 'ok'.
-doterl_compile(Config, Dir) ->
-    ErlOpts = rebar_utils:erl_opts(Config),
-    doterl_compile(Config, Dir, [], ErlOpts).
+-spec doterl_compile(rebar_state:t(), file:filename()) -> ok.
+doterl_compile(State, Dir) ->
+    ErlOpts = rebar_utils:erl_opts(State),
+    doterl_compile(State, Dir, [], ErlOpts).
 
 doterl_compile(Config, Dir, MoreSources, ErlOpts) ->
     OutDir = filename:join(Dir, "ebin"),
@@ -634,16 +634,19 @@ compile_yrl(Source, Target, Config) ->
 -spec compile_xrl_yrl(rebar_state:t(), file:filename(),
                       file:filename(), list(), module()) -> 'ok'.
 compile_xrl_yrl(Config, Source, Target, Opts, Mod) ->
+    Dir = rebar_state:dir(Config),
+    Opts1 = [{includefile, filename:join(Dir, I)} || {includefile, I} <- Opts,
+                                                     filename:pathtype(I) =:= relative],
     case needs_compile(Source, Target, []) of
         true ->
-            case Mod:file(Source, Opts ++ [{return, true}]) of
+            case Mod:file(Source, Opts1 ++ [{return, true}]) of
                 {ok, _} ->
                     ok;
                 {ok, _Mod, Ws} ->
                     rebar_base_compiler:ok_tuple(Config, Source, Ws);
                 {error, Es, Ws} ->
                     rebar_base_compiler:error_tuple(Config, Source,
-                                                    Es, Ws, Opts)
+                                                    Es, Ws, Opts1)
             end;
         false ->
             skipped
diff --git a/src/rebar_fetch.erl b/src/rebar_fetch.erl
index 6b31f6c..0a90848 100644
--- a/src/rebar_fetch.erl
+++ b/src/rebar_fetch.erl
@@ -49,14 +49,16 @@ lock_source(_AppDir, Source) ->
 download_source(AppDir, Source) ->
     TmpDir = ec_file:insecure_mkdtemp(),
     AppDir1 = ec_cnv:to_list(AppDir),
+    ec_file:mkdir_p(AppDir1),
     case download_source_tmp(TmpDir, Source) of
         {ok, _} ->
-            ec_file:mkdir_p(AppDir1),
             ok = ec_file:copy(TmpDir, filename:absname(AppDir1), [recursive]);
         {tarball, File} ->
-            ok = erl_tar:extract(File, [{cwd,
-                                         (filename:dirname(filename:absname(AppDir1)))}
-                                        ,compressed])
+            ok = erl_tar:extract(File, [{cwd, TmpDir}
+                                        ,compressed]),
+            BaseName = filename:basename(AppDir1),
+            [FromDir] = filelib:wildcard(filename:join(TmpDir, BaseName++"-*")),
+            ec_file:copy(FromDir, AppDir1, [recursive])
     end.
 
 download_source_tmp(TmpDir, {p4, Url}) ->
diff --git a/src/rebar_packages.erl b/src/rebar_packages.erl
index 103d3a3..cd979fa 100644
--- a/src/rebar_packages.erl
+++ b/src/rebar_packages.erl
@@ -4,7 +4,7 @@
 
 -include("rebar.hrl").
 
--spec get_packages(rebar_state:t()) -> {list(), rlx_depsolver:t()}.
+-spec get_packages(rebar_state:t()) -> {rebar_dict(), rlx_depsolver:t()}.
 get_packages(State) ->
     RebarDir = rebar_state:get(State, global_rebar_dir, filename:join(os:getenv("HOME"), ".rebar")),
     PackagesFile = filename:join(RebarDir, "packages"),
@@ -12,12 +12,13 @@ get_packages(State) ->
         true ->
             try
                 {ok, Binary} = file:read_file(PackagesFile),
-                binary_to_term(Binary)
+                {Dict, Graph} = binary_to_term(Binary),
+                {Dict, Graph}
             catch
                 _:_ ->
                     ?ERROR("Bad packages index, try to fix with `rebar update`~n", []),
-                    {[], rlx_depsolver:new()}
+                    {dict:new(), rlx_depsolver:new_graph()}
             end;
         false ->
-            {[], rlx_depsolver:new()}
+            {dict:new(), rlx_depsolver:new_graph()}
     end.
diff --git a/src/rebar_plugins.erl b/src/rebar_plugins.erl
index 0fdbc6d..b180ede 100644
--- a/src/rebar_plugins.erl
+++ b/src/rebar_plugins.erl
@@ -3,10 +3,36 @@
 
 -module(rebar_plugins).
 
--export([]).
+-export([install/1]).
 
 -include("rebar.hrl").
 
 %% ===================================================================
 %% Public API
 %% ===================================================================
+
+install(State) ->
+    State1 = rebar_state:set(State, deps_dir, ?DEFAULT_PLUGINS_DIR),
+
+    Plugins = rebar_state:get(State1, plugins, []),
+    {ok, State2} = rebar_prv_install_deps:handle_deps(State1, Plugins),
+
+    Apps = rebar_state:get(State2, all_deps, []),
+    ToBuild = lists:dropwhile(fun rebar_app_info:valid/1, Apps),
+    lists:foreach(fun(AppInfo) ->
+                          C = rebar_config:consult(rebar_app_info:dir(AppInfo)),
+                          S = rebar_state:new(rebar_state:new(), C, rebar_app_info:dir(AppInfo)),
+                          rebar_prv_compile:build(S, AppInfo)
+                  end, ToBuild),
+
+    PluginProviders = plugin_providers(Plugins),
+    {ok, PluginProviders, rebar_state:set(State2, deps_dir, ?DEFAULT_DEPS_DIR)}.
+
+plugin_providers(Plugins) ->
+    lists:map(fun({Plugin, _, _}) when is_atom(Plugin) ->
+                      Plugin;
+                 ({Plugin, _}) when is_atom(Plugin) ->
+                      Plugin;
+                 (Plugin) when is_atom(Plugin) ->
+                      Plugin
+              end, Plugins).
diff --git a/src/rebar_provider.erl b/src/rebar_provider.erl
deleted file mode 100644
index e5d7520..0000000
--- a/src/rebar_provider.erl
+++ /dev/null
@@ -1,165 +0,0 @@
--module(rebar_provider).
-
-%% API
--export([new/2,
-         do/2,
-         impl/1,
-         get_provider/2,
-         get_target_providers/2,
-         help/1,
-         format/1]).
-
--export_type([t/0]).
-
--include("rebar.hrl").
-
-%%%===================================================================
-%%% Types
-%%%===================================================================
-
--opaque t() :: record(provider).
-
--type provider_name() :: atom().
-
--ifdef(have_callback_support).
-
--callback init(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
--callback do(rebar_state:t()) ->  {ok, rebar_state:t()} | relx:error().
-
--else.
-
-%% In the case where R14 or lower is being used to compile the system
-%% we need to export a behaviour info
--export([behaviour_info/1]).
--spec behaviour_info(atom()) -> [{atom(), arity()}] | undefined.
-behaviour_info(callbacks) ->
-    [{init, 1},
-     {do, 1}];
-behaviour_info(_) ->
-    undefined.
-
--endif.
-
-%%%===================================================================
-%%% API
-%%%===================================================================
-
-%% @doc create a new provider object from the specified module. The
-%% module should implement the provider behaviour.
-%%
-%% @param ModuleName The module name.
-%% @param State0 The current state of the system
--spec new(module(), rebar_state:t()) ->
-                 {ok, rebar_state:t()}.
-new(ModuleName, State0) when is_atom(ModuleName) ->
-    case code:which(ModuleName) of
-        non_existing ->
-            ?ERROR("Module ~p does not exist.", [ModuleName]);
-        _ ->
-            ModuleName:init(State0)
-    end.
-
-%% @doc Manipulate the state of the system, that new state
-%%
-%% @param Provider the provider object
-%% @param State the current state of the system
--spec do(Provider::t(), rebar_state:t()) ->
-                {ok, rebar_state:t()}.
-do(Provider, State) ->
-    {PreHooks, PostHooks} = rebar_state:hooks(State, Provider#provider.name),
-    {ok, State1} = run_hook_plugins(PreHooks, State),
-    {ok, State2} = (Provider#provider.provider_impl):do(State1),
-    run_hook_plugins(PostHooks, State2).
-
-run_hook_plugins(Hooks, State) ->
-    State1 = lists:foldl(fun(Hook, StateAcc) ->
-                                 {ok, StateAcc1} = rebar_provider:do(Hook, StateAcc),
-                                 StateAcc1
-                         end, State, Hooks),
-    {ok, State1}.
-
-%%% @doc get the name of the module that implements the provider
-%%% @param Provider the provider object
--spec impl(Provider::t()) -> module().
-impl(Provider) ->
-    Provider#provider.name.
-
-help(State) ->
-    Providers = rebar_state:providers(State),
-    Help = lists:sort([{ec_cnv:to_list(P#provider.name), P#provider.short_desc} || P <- Providers,
-                                                                                   P#provider.bare =/= true]),
-    Longest = lists:max([length(X) || {X, _} <- Help]),
-
-    lists:foreach(fun({Name, ShortDesc}) ->
-                          Length = length(Name),
-                          Spacing = lists:duplicate(Longest - Length + 8, " "),
-                          io:format("~s~s~s~n", [Name, Spacing, ShortDesc])
-                  end, Help).
-
-
-%% @doc print the provider module name
-%%
-%% @param T - The provider
-%% @return An iolist describing the provider
--spec format(t()) -> iolist().
-format(#provider{name=Name}) ->
-    atom_to_list(Name).
-
-get_target_providers(Target, State) ->
-    Providers = rebar_state:providers(State),
-    TargetProviders = lists:filter(fun(#provider{name=T}) when T =:= Target->
-                                           true;
-                                      (#provider{name=T}) ->
-                                           false
-                                   end, Providers),
-    process_deps(TargetProviders, Providers).
-
--spec get_provider(provider_name(), [t()]) -> t().
-get_provider(ProviderName, [Provider = #provider{name = ProviderName} | _]) ->
-    Provider;
-get_provider(ProviderName, [_ | Rest]) ->
-    get_provider(ProviderName, Rest);
-get_provider(_ProviderName, _) ->
-    [].
-
-process_deps([], _Providers) ->
-    [];
-process_deps(TargetProviders, Providers) ->
-    DepChain = lists:flatmap(fun(Provider) ->
-                                     {DC, _, _} = process_deps(Provider, Providers, []),
-                                     DC
-                             end, TargetProviders),
-    ['NONE' | Rest] =
-        reorder_providers(lists:flatten([{'NONE', P#provider.name} || P <- TargetProviders] ++ DepChain)),
-    Rest.
-
-process_deps(Provider, Providers, Seen) ->
-    case lists:member(Provider, Seen) of
-        true ->
-            {[], Providers, Seen};
-        false ->
-            Deps = Provider#provider.deps,
-            DepList = lists:map(fun(Dep) ->
-                                        {Dep, Provider#provider.name}
-                                end, Deps),
-            {NewDeps, _, NewSeen} =
-                lists:foldl(fun(Arg, Acc) ->
-                                    process_dep(Arg, Acc)
-                            end,
-                           {[], Providers, Seen}, Deps),
-            {[DepList | NewDeps], Providers, NewSeen}
-    end.
-
-process_dep(ProviderName, {Deps, Providers, Seen}) ->
-    Provider = get_provider(ProviderName, Providers),
-    {NewDeps, _, NewSeen} = process_deps(Provider, Providers, [ProviderName | Seen]),
-    {[Deps | NewDeps], Providers, NewSeen}.
-
-%% @doc Reorder the providers according to thier dependency set.
-reorder_providers(OProviderList) ->
-    case rebar_topo:sort(OProviderList) of
-        {ok, ProviderList} ->
-            ProviderList;
-        {cycle, _} ->
-            ?ERROR("There was a cycle in the provider list. Unable to complete build!", [])
-    end.
diff --git a/src/rebar_prv_app_discovery.erl b/src/rebar_prv_app_discovery.erl
index 897a38d..e2dcf23 100644
--- a/src/rebar_prv_app_discovery.erl
+++ b/src/rebar_prv_app_discovery.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_app_discovery).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,18 +20,22 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = true,
-                                                       deps = ?DEPS,
-                                                       example = "",
-                                                       short_desc = "",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, true},
+                                                               {deps, ?DEPS},
+                                                               {example, ""},
+                                                               {short_desc, ""},
+                                                               {desc, ""},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     LibDirs = rebar_state:get(State, lib_dirs, ?DEFAULT_LIB_DIRS),
     State1 = rebar_app_discover:do(State, LibDirs),
     {ok, State1}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
diff --git a/src/rebar_prv_clean.erl b/src/rebar_prv_clean.erl
new file mode 100644
index 0000000..72b85dc
--- /dev/null
+++ b/src/rebar_prv_clean.erl
@@ -0,0 +1,44 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+
+-module(rebar_prv_clean).
+
+-behaviour(provider).
+
+-export([init/1,
+         do/1,
+         format_error/2]).
+
+-include("rebar.hrl").
+
+-define(PROVIDER, clean).
+-define(DEPS, [app_discovery]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
+init(State) ->
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar clean"},
+                                                               {short_desc, "Remove compiled beam files from apps."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
+    {ok, State1}.
+
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+    ProjectApps = rebar_state:project_apps(State),
+    lists:foreach(fun(AppInfo) ->
+                          ?INFO("Cleaning out ~s...~n", [rebar_app_info:name(AppInfo)]),
+                          rebar_erlc_compiler:clean(State, ec_cnv:to_list(rebar_app_info:dir(AppInfo)))
+                  end, ProjectApps),
+    {ok, State}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
diff --git a/src/rebar_prv_common_test.erl b/src/rebar_prv_common_test.erl
index b880d77..37d1920 100644
--- a/src/rebar_prv_common_test.erl
+++ b/src/rebar_prv_common_test.erl
@@ -6,6 +6,7 @@
 -behaviour(rebar_provider).
 
 -export([init/1,
+         format_error/2,
          do/1]).
 
 -include("rebar.hrl").
@@ -19,15 +20,15 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State,
-                                      #provider{name = ?PROVIDER,
-                                                provider_impl = ?MODULE,
-                                                bare = false,
-                                                deps = ?DEPS,
-                                                example = "rebar ct",
-                                                short_desc = "Run Common Tests",
-                                                desc = "",
-                                                opts = []}),
+    Provider = providers:create([{name, ?PROVIDER},
+                                 {module, ?MODULE},
+                                 {deps, ?DEPS},
+                                 {bare, false},
+                                 {example, "rebar ct"},
+                                 {short_desc, "Run Common Tests"},
+                                 {desc, ""},
+                                 {opts, ct_opts(State)}]),
+    State1 = rebar_state:add_provider(State, Provider),
     {ok, State1}.
 
 -spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
@@ -36,6 +37,106 @@ do(State) ->
     ct:run_test(Opts),
     {ok, State}.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
+ct_opts(State) ->
+    DefaultTestDir = filename:join([rebar_state:dir(State), "test"]),
+    DefaultLogsDir = filename:join([rebar_state:dir(State), "logs"]),
+    [{dir, undefined, "dir", {string, DefaultTestDir}, help(dir)}, %% dir
+     {suite, undefined, "suite", string, help(suite)}, %% comma-seperated list
+     {group, undefined, "group", string, help(group)}, %% comma-seperated list
+     {testcase, undefined, "case", string, help(testcase)}, %% comma-seperated list
+     {spec, undefined, "spec", string, help(spec)}, %% comma-seperated list
+     {join_specs, undefined, "join_specs", boolean, help(join_specs)}, %% Boolean
+     {label, undefined, "label", string, help(label)}, %% String
+     {config, undefined, "config", string, help(config)}, %% comma-seperated list
+     {userconfig, undefined, "userconfig", string, help(userconfig)}, %% [{CallbackMod, CfgStrings}] | {CallbackMod, CfgStrings}
+     {allow_user_terms, undefined, "allow_user_terms", boolean, help(allow_user_terms)}, %% Bool
+     {logdir, undefined, "logdir", {string, DefaultLogsDir}, help(logdir)}, %% string
+     {logopts, undefined, "logopts", string, help(logopts)}, %% enum, no_nl | no_src
+     {verbosity, undefined, "verbosity", string, help(verbosity)}, %% Integer OR [{Category, VLevel}]
+     {silent_connections, undefined, "silent_connections", string,
+      help(silent_connections)}, % all OR %% comma-seperated list
+     {stylesheet, undefined, "stylesheet", string, help(stylesheet)}, %% file
+     {cover, undefined, "cover", string, help(cover)}, %% file
+     {cover_stop, undefined, "cover_stop", boolean, help(cover_stop)}, %% Boolean
+     {event_handler, undefined, "event_handler", string, help(event_handler)}, %% EH | [EH] WHERE EH atom() | {atom(), InitArgs} | {[atom()], InitArgs}
+     {include, undefined, "include", string, help(include)},
+     {abort_if_missing_suites, undefined, "abort_if_missing_suites", {boolean, true},
+      help(abort_if_missing_suites)}, %% boolean
+     {multiply_timetraps, undefined, "multiply_timetraps", integer,
+      help(multiply_timetraps)}, %% integer
+     {scale_timetraps, undefined, "scale_timetraps", boolean, help(scale_timetraps)}, %% Boolean
+     {create_priv_dir, undefined, "create_priv_dir", string, help(create_priv_dir)}, %% enum: auto_per_run | auto_per_tc | manual_per_tc
+     {repeat, undefined, "repeat", integer, help(repeat)}, %% integer
+     {duration, undefined, "duration", string, help(duration)}, % format: HHMMSS
+     {until, undefined, "until", string, help(until)}, %% format: YYMoMoDD[HHMMSS]
+     {force_stop, undefined, "force_stop", string, help(force_stop)}, % enum: skip_rest, bool
+     {basic_html, undefined, "basic_html", boolean, help(basic_html)}, %% Booloean
+     {ct_hooks, undefined, "ct_hooks", string, help(ct_hooks)} %% List: [CTHModule | {CTHModule, CTHInitArgs}] where CTHModule is atom CthInitArgs is term
+    ].
+
+help(dir) ->
+    "Test folder (default: test/)";
+help(suite) ->
+    "List of test suites to run";
+help(group) ->
+    "List of test groups to run";
+help(testcase) ->
+    "List of test cases to run";
+help(spec) ->
+    "List of test specs to run";
+help(join_specs) ->
+    ""; %% ??
+help(label) ->
+    "Test label";
+help(config) ->
+    "List of config files";
+help(allow_user_terms) ->
+    ""; %% ??
+help(logdir) ->
+    "Log folder";
+help(logopts) ->
+    ""; %% ??
+help(verbosity) ->
+    "Verbosity";
+help(silent_connections) ->
+    ""; %% ??
+help(stylesheet) ->
+    "Stylesheet to use for test results";
+help(cover) ->
+    "Cover file to use";
+help(cover_stop) ->
+    ""; %% ??
+help(event_handler) ->
+    "Event handlers to attach to the runner";
+help(include) ->
+    "Include folder";
+help(abort_if_missing_suites) ->
+    "Abort if suites are missing";
+help(multiply_timetraps) ->
+    ""; %% ??
+help(scale_timetraps) ->
+    ""; %% ??
+help(create_priv_dir) ->
+    ""; %% ??
+help(repeat) ->
+    "How often to repeat tests";
+help(duration) ->
+    "Max runtime (format: HHMMSS)";
+help(until) ->
+    "Run until (format: HHMMSS)";
+help(force_stop) ->
+    "Force stop after time";
+help(basic_html) ->
+    "Show basic HTML";
+help(ct_hooks) ->
+    "";
+help(userconfig) ->
+    "".
+
 build_options(State) ->
     Arguments = rebar_state:command_args(State),
     Opts = parse_args(Arguments, []),
diff --git a/src/rebar_prv_compile.erl b/src/rebar_prv_compile.erl
index d89a4b0..30611cd 100644
--- a/src/rebar_prv_compile.erl
+++ b/src/rebar_prv_compile.erl
@@ -1,9 +1,10 @@
 -module(rebar_prv_compile).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
          do/1,
+         format_error/2,
          build/2]).
 
 -include("rebar.hrl").
@@ -11,34 +12,48 @@
 -define(PROVIDER, compile).
 -define(DEPS, [lock]).
 
+-define(DEFAULT_JOBS, 3).
+
 %% ===================================================================
 %% Public API
 %% ===================================================================
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                        provider_impl = ?MODULE,
-                                                        bare = false,
-                                                        deps = ?DEPS,
-                                                        example = "rebar compile",
-                                                        short_desc = "Compile apps .app.src and .erl files.",
-                                                        desc = "",
-                                                        opts = []}),
+    JobsHelp = io_lib:format(
+                 "Number of concurrent workers the compiler may use. Default: ~B",
+                 [?DEFAULT_JOBS]),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar compile"},
+                                                               {short_desc, "Compile apps .app.src and .erl files."},
+                                                               {desc, ""},
+                                                               {opts, [
+                                                                      {jobs,     $j, "jobs",     integer,   JobsHelp}
+                                                                      ]}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
-    ProjectApps = rebar_state:project_apps(State),
-    Deps = rebar_state:get(State, deps_to_build, []),
+    {ok, State1} = handle_args(State),
+
+    ProjectApps = rebar_state:project_apps(State1),
+    Deps = rebar_state:get(State1, deps_to_build, []),
 
     lists:foreach(fun(AppInfo) ->
-                          C = rebar_config:consult(rebar_app_info:dir(AppInfo)),
-                          S = rebar_state:new(rebar_state:new(), C, rebar_app_info:dir(AppInfo)),
+                          AppDir = rebar_app_info:dir(AppInfo),
+                          C = rebar_config:consult(AppDir),
+                          S = rebar_state:new(State1, C, AppDir),
                           build(S, AppInfo)
                   end, Deps++ProjectApps),
 
-    {ok, State}.
+    {ok, State1}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
 
 build(State, AppInfo) ->
     ?INFO("Compiling ~s~n", [rebar_app_info:name(AppInfo)]),
@@ -49,3 +64,8 @@ build(State, AppInfo) ->
 %% ===================================================================
 %% Internal functions
 %% ===================================================================
+
+handle_args(State) ->
+    {Args, _} = rebar_state:command_parsed_args(State),
+    Jobs = proplists:get_value(jobs, Args, ?DEFAULT_JOBS),
+    {ok, rebar_state:set(State, jobs, Jobs)}.
diff --git a/src/rebar_prv_deps.erl b/src/rebar_prv_deps.erl
index 111f32f..80122ac 100644
--- a/src/rebar_prv_deps.erl
+++ b/src/rebar_prv_deps.erl
@@ -1,9 +1,10 @@
 -module(rebar_prv_deps).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -12,20 +13,24 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = true,
-                                                       deps = ?DEPS,
-                                                       example = "rebar deps",
-                                                       short_desc = "List dependencies",
-                                                       desc = info("List dependencies"),
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, true},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar deps"},
+                                                               {short_desc, "List dependencies"},
+                                                               {desc, info("List dependencies")},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     {ok, State}.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
 info(Description) ->
     io_lib:format("~s.~n"
                  "~n"
diff --git a/src/rebar_prv_do.erl b/src/rebar_prv_do.erl
index a2ac648..e66fdbd 100644
--- a/src/rebar_prv_do.erl
+++ b/src/rebar_prv_do.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_do).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,27 +20,30 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar3 do <task1>, <task2>, ...",
-                                                       short_desc = "Higher order provider for running multiple tasks in a sequence.",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar3 do <task1>, <task2>, ..."},
+                                                               {short_desc, "Higher order provider for running multiple tasks in a sequence."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     Tasks = args_to_tasks(rebar_state:command_args(State)),
-    State1 = lists:foldl(fun(TaskArgs, StateAcc) ->
+    lists:foldl(fun(TaskArgs, {ok, StateAcc}) ->
                                  [TaskStr | Args] = string:tokens(TaskArgs, " "),
                                  Task = list_to_atom(TaskStr),
                                  StateAcc1 = rebar_state:set(StateAcc, task, Task),
                                  StateAcc2 = rebar_state:command_args(StateAcc1, Args),
                                  rebar_core:process_command(StateAcc2, Task)
-                       end, State, Tasks),
-    {ok, State1}.
+                       end, {ok, State}, Tasks).
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
 
 args_to_tasks(Args) ->
     [string:strip(T) || T <- string:tokens(string:join(Args, " "), ",")].
diff --git a/src/rebar_erlydtl_compiler.erl b/src/rebar_prv_erlydtl_compiler.erl
index 88ee20f..8d80cdd 100644
--- a/src/rebar_erlydtl_compiler.erl
+++ b/src/rebar_prv_erlydtl_compiler.erl
@@ -92,12 +92,13 @@
 %%          {doc_root, "templates"}, {module_ext, ""}, {source_ext, ".html"}
 %%      ]
 %%   ]}.
--module(rebar_erlydtl_compiler).
+-module(rebar_prv_erlydtl_compiler).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 %% for internal use only
 -export([info/2]).
@@ -113,22 +114,23 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar erlydtl compile",
-                                                       short_desc = "Compile erlydtl templates.",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar erlydtl compile"},
+                                                               {short_desc, "Compile erlydtl templates."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
     {ok, State1}.
 
 do(Config) ->
     MultiDtlOpts = erlydtl_opts(Config),
     OrigPath = code:get_path(),
-    true = code:add_path(rebar_utils:ebin_dir()),
+    %true = code:add_path(rebar_utils:ebin_dir()),
 
     Result = lists:foldl(fun(DtlOpts, _) ->
+                                 file:make_dir(option(out_dir, DtlOpts)),
                                  rebar_base_compiler:run(Config, [],
                                                          option(doc_root, DtlOpts),
                                                          option(source_ext, DtlOpts),
@@ -144,6 +146,10 @@ do(Config) ->
     true = code:set_path(OrigPath),
     {Result, Config}.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
 %% ===================================================================
 %% Internal functions
 %% ===================================================================
@@ -230,24 +236,15 @@ do_compile(Config, Source, Target, DtlOpts) ->
     Opts = lists:ukeymerge(1, DtlOpts, Sorted),
     ?INFO("Compiling \"~s\" -> \"~s\" with options:~n    ~s~n",
         [Source, Target, io_lib:format("~p", [Opts])]),
-    case erlydtl:compile(Source,
-                         module_name(Target),
+    case erlydtl:compile_file(ec_cnv:to_list(Source),
+                         list_to_atom(module_name(Target)),
                          Opts) of
-        ok ->
-            ok;
         {ok, _Mod} ->
             ok;
         {ok, _Mod, Ws} ->
             rebar_base_compiler:ok_tuple(Config, Source, Ws);
-        {ok, _Mod, _Bin, Ws} ->
-            rebar_base_compiler:ok_tuple(Config, Source, Ws);
         error ->
             rebar_base_compiler:error_tuple(Config, Source, [], [], Opts);
-        {error, {_File, _Msgs} = Error} ->
-            rebar_base_compiler:error_tuple(Config, Source, [Error], [], Opts);
-        {error, Msg} ->
-            Es = [{Source, [{erlydtl_parser, Msg}]}],
-            rebar_base_compiler:error_tuple(Config, Source, Es, [], Opts);
         {error, Es, Ws} ->
             rebar_base_compiler:error_tuple(Config, Source, Es, Ws, Opts)
     end.
diff --git a/src/rebar_prv_escripter.erl b/src/rebar_prv_escripter.erl
deleted file mode 100644
index 418ac6c..0000000
--- a/src/rebar_prv_escripter.erl
+++ /dev/null
@@ -1,224 +0,0 @@
-%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
-%% ex: ts=4 sw=4 et
-%% -------------------------------------------------------------------
-%%
-%% rebar: Erlang Build Tools
-%%
-%% Copyright (c) 2009 Dave Smith (dizzyd@dizzyd.com)
-%%
-%% Permission is hereby granted, free of charge, to any person obtaining a copy
-%% of this software and associated documentation files (the "Software"), to deal
-%% in the Software without restriction, including without limitation the rights
-%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-%% copies of the Software, and to permit persons to whom the Software is
-%% furnished to do so, subject to the following conditions:
-%%
-%% The above copyright notice and this permission notice shall be included in
-%% all copies or substantial portions of the Software.
-%%
-%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-%% THE SOFTWARE.
-%% -------------------------------------------------------------------
--module(rebar_prv_escripter).
-
--behaviour(rebar_provider).
-
--export([init/1,
-         do/1]).
-
--export([escriptize/2,
-         clean/2]).
-
-%% for internal use only
--export([info/2]).
-
--include("rebar.hrl").
--include_lib("kernel/include/file.hrl").
-
--define(PROVIDER, escriptize).
--define(DEPS, [app_builder]).
-
-%% ===================================================================
-%% Public API
-%% ===================================================================
-
--spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
-init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                        provider_impl = ?MODULE,
-                                                        bare = false,
-                                                        deps = ?DEPS,
-                                                        example = "rebar escriptize",
-                                                        short_desc = "Build escript from project.",
-                                                        desc = "",
-                                                        opts = []}),
-    {ok, State1}.
-
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
-do(Config) ->
-    AppName = rebar_state:get_local(Config, escript_top_level_app, undefined),
-    App = rebar_state:get_app(Config, AppName),
-    {ok, Config1} = escriptize(Config, rebar_app_info:app_file(App)),
-    {ok, Config1}.
-
-escriptize(Config0, AppFile) ->
-    %% Extract the application name from the archive -- this is the default
-    %% name of the generated script
-    {Config, AppName} = rebar_app_utils:app_name(Config0, AppFile),
-    AppNameStr = atom_to_list(AppName),
-
-    %% Get the output filename for the escript -- this may include dirs
-    Filename = rebar_state:get_local(Config, escript_name, AppName),
-    ok = filelib:ensure_dir(Filename),
-
-    %% Look for a list of other applications (dependencies) to include
-    %% in the output file. We then use the .app files for each of these
-    %% to pull in all the .beam files.
-    InclBeams = get_app_beams(
-                  rebar_state:get_local(Config, escript_incl_apps, []), []),
-
-    %% Look for a list of extra files to include in the output file.
-    %% For internal rebar-private use only. Do not use outside rebar.
-    InclExtra = get_extra(Config),
-
-    %% Construct the archive of everything in ebin/ dir -- put it on the
-    %% top-level of the zip file so that code loading works properly.
-    EbinPrefix = filename:join(AppNameStr, "ebin"),
-    EbinFiles = usort(load_files(EbinPrefix, "*", "ebin")),
-    ExtraFiles = usort(InclBeams ++ InclExtra),
-    Files = EbinFiles ++ ExtraFiles,
-
-    case zip:create("mem", Files, [memory]) of
-        {ok, {"mem", ZipBin}} ->
-            %% Archive was successfully created. Prefix that binary with our
-            %% header and write to our escript file
-            Shebang = rebar_state:get(Config, escript_shebang,
-                                       "#!/usr/bin/env escript\n"),
-            Comment = rebar_state:get(Config, escript_comment, "%%\n"),
-            DefaultEmuArgs = ?FMT("%%! -pa ~s/~s/ebin\n",
-                                  [AppNameStr, AppNameStr]),
-            EmuArgs = rebar_state:get(Config, escript_emu_args,
-                                       DefaultEmuArgs),
-            Script = iolist_to_binary([Shebang, Comment, EmuArgs, ZipBin]),
-            case file:write_file(Filename, Script) of
-                ok ->
-                    ok;
-                {error, WriteError} ->
-                    ?ERROR("Failed to write ~p script: ~p\n",
-                           [AppName, WriteError]),
-                    ?FAIL
-            end;
-        {error, ZipError} ->
-            ?ERROR("Failed to construct ~p escript: ~p\n",
-                   [AppName, ZipError]),
-            ?FAIL
-    end,
-
-    %% Finally, update executable perms for our script
-    {ok, #file_info{mode = Mode}} = file:read_file_info(Filename),
-    ok = file:change_mode(Filename, Mode bor 8#00111),
-    {ok, Config}.
-
-clean(Config0, AppFile) ->
-    %% Extract the application name from the archive -- this is the default
-    %% name of the generated script
-    {Config, AppName} = rebar_app_utils:app_name(Config0, AppFile),
-
-    %% Get the output filename for the escript -- this may include dirs
-    Filename = rebar_state:get_local(Config, escript_name, AppName),
-    rebar_file_utils:delete_each([Filename]),
-    {ok, Config}.
-
-%% ===================================================================
-%% Internal functions
-%% ===================================================================
-
-info(help, escriptize) ->
-    info_help("Generate escript archive");
-info(help, clean) ->
-    info_help("Delete generated escript archive").
-
-info_help(Description) ->
-    ?CONSOLE(
-       "~s.~n"
-       "~n"
-       "Valid rebar.config options:~n"
-       "  ~p~n"
-       "  ~p~n"
-       "  ~p~n"
-       "  ~p~n"
-       "  ~p~n",
-       [
-        Description,
-        {escript_name, "application"},
-        {escript_incl_apps, []},
-        {escript_shebang, "#!/usr/bin/env escript\n"},
-        {escript_comment, "%%\n"},
-        {escript_emu_args, "%%! -pa application/application/ebin\n"}
-       ]).
-
-get_app_beams([], Acc) ->
-    Acc;
-get_app_beams([App | Rest], Acc) ->
-    case code:lib_dir(App, ebin) of
-        {error, bad_name} ->
-            ?ABORT("Failed to get ebin/ directory for "
-                   "~p escript_incl_apps.", [App]);
-        Path ->
-            Prefix = filename:join(atom_to_list(App), "ebin"),
-            Acc2 = load_files(Prefix, "*", Path),
-            get_app_beams(Rest, Acc2 ++ Acc)
-    end.
-
-get_extra(Config) ->
-    Extra = rebar_state:get_local(Config, escript_incl_extra, []),
-    lists:foldl(fun({Wildcard, Dir}, Files) ->
-                        load_files(Wildcard, Dir) ++ Files
-                end, [], Extra).
-
-load_files(Wildcard, Dir) ->
-    load_files("", Wildcard, Dir).
-
-load_files(Prefix, Wildcard, Dir) ->
-    [read_file(Prefix, Filename, Dir)
-     || Filename <- filelib:wildcard(Wildcard, Dir)].
-
-read_file(Prefix, Filename, Dir) ->
-    Filename1 = case Prefix of
-                    "" ->
-                        Filename;
-                    _ ->
-                        filename:join([Prefix, Filename])
-                end,
-    [dir_entries(filename:dirname(Filename1)),
-     {Filename1, file_contents(filename:join(Dir, Filename))}].
-
-file_contents(Filename) ->
-    {ok, Bin} = file:read_file(Filename),
-    Bin.
-
-%% Given a filename, return zip archive dir entries for each sub-dir.
-%% Required to work around issues fixed in OTP-10071.
-dir_entries(File) ->
-    Dirs = dirs(File),
-    [{Dir ++ "/", <<>>} || Dir <- Dirs].
-
-%% Given "foo/bar/baz", return ["foo", "foo/bar", "foo/bar/baz"].
-dirs(Dir) ->
-    dirs1(filename:split(Dir), "", []).
-
-dirs1([], _, Acc) ->
-    lists:reverse(Acc);
-dirs1([H|T], "", []) ->
-    dirs1(T, H, [H]);
-dirs1([H|T], Last, Acc) ->
-    Dir = filename:join(Last, H),
-    dirs1(T, Dir, [Dir|Acc]).
-
-usort(List) ->
-    lists:ukeysort(1, lists:flatten(List)).
diff --git a/src/rebar_prv_help.erl b/src/rebar_prv_help.erl
index a9949e7..8300378 100644
--- a/src/rebar_prv_help.erl
+++ b/src/rebar_prv_help.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_help).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,30 +20,49 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar help <task>",
-                                                       short_desc = "Display a list of tasks or help for a given task or subtask.",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar help <task>"},
+                                                               {short_desc, "Display a list of tasks or help for a given task or subtask."},
+                                                               {desc, "Display a list of tasks or help for a given task or subtask."},
+                                                               {opts, [
+                                                                      {help_task, undefined, undefined, string, "Task to print help for."}
+                                                                      ]}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
-    help(State),
-    {ok, State}.
+    {Args, _} = rebar_state:command_parsed_args(State),
+    case proplists:get_value(help_task, Args, undefined) of
+        undefined ->
+            help(State),
+            {ok, State};
+        Name ->
+            Providers = rebar_state:providers(State),
+            case providers:get_provider(list_to_atom(Name), Providers) of
+                not_found ->
+                    {error, io_lib:format("Unknown task ~s", [Name])};
+                Provider ->
+                    providers:help(Provider),
+                    {ok, State}
+            end
+    end.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
 
 %%
 %% print help/usage string
 %%
 help(State) ->
     ?CONSOLE("Rebar is a tool for working with Erlang projects.~n~n", []),
-    OptSpecList = rebar3:option_spec_list(),
+    OptSpecList = rebar3:global_option_spec_list(),
     getopt:usage(OptSpecList, "rebar", "", []),
     ?CONSOLE("~nSeveral tasks are available:~n", []),
 
-    rebar_provider:help(State),
+    providers:help(rebar_state:providers(State)),
 
     ?CONSOLE("~nRun 'rebar help <TASK>' for details.~n~n", []).
diff --git a/src/rebar_prv_install_deps.erl b/src/rebar_prv_install_deps.erl
index d20f2b5..522420d 100644
--- a/src/rebar_prv_install_deps.erl
+++ b/src/rebar_prv_install_deps.erl
@@ -26,14 +26,16 @@
 %% -------------------------------------------------------------------
 -module(rebar_prv_install_deps).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
--export([setup_env/1]).
+-export([handle_deps/2,
+         handle_deps/3]).
 
 %% for internal use only
 -export([get_deps_dir/1]).
@@ -43,9 +45,9 @@
 -define(DEPS, [app_discovery]).
 
 -type src_dep() :: {atom(), string(), {atom(), string(), string()}}.
--type binary_dep() :: {atom(), binary()} | atom().
+-type pkg_dep() :: {atom(), binary()} | atom().
 
--type dep() :: src_dep() | binary_dep().
+-type dep() :: src_dep() | pkg_dep().
 
 %% ===================================================================
 %% Public API
@@ -53,174 +55,237 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = true,
-                                                       deps = ?DEPS,
-                                                       example = undefined,
-                                                       short_desc = "Install dependencies",
-                                                       desc = info("Install dependencies"),
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, true},
+                                                               {deps, ?DEPS},
+                                                               {example, undefined},
+                                                               {short_desc, "Install dependencies"},
+                                                               {desc, info("Install dependencies")},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
-    case rebar_state:get(State, locks, []) of
-        [] ->
-            handle_deps(State, ordsets:from_list(rebar_state:get(State, deps, [])));
-        Locks ->
-            handle_deps(State, ordsets:from_list(Locks))
+    ProjectApps = rebar_state:project_apps(State),
+    {ok, State1} = case rebar_state:get(State, locks, []) of
+                       [] ->
+                           handle_deps(State, rebar_state:get(State, deps, []));
+                       Locks ->
+                           handle_deps(State, Locks)
+                   end,
+
+    Source = ProjectApps ++ rebar_state:src_apps(State1),
+    case rebar_topo:sort_apps(Source) of
+        {ok, Sort} ->
+            {ok, rebar_state:set(State1, deps_to_build, lists:dropwhile(fun rebar_app_info:valid/1, Sort -- ProjectApps))};
+        {error, Error} ->
+            {error, Error}
     end.
 
-%% set REBAR_DEPS_DIR and ERL_LIBS environment variables
-setup_env(State) ->
-    DepsDir = get_deps_dir(State),
-    %% include rebar's DepsDir in ERL_LIBS
-    Separator = case os:type() of
-                    {win32, nt} ->
-                        ";";
-                    _ ->
-                        ":"
-                end,
-    ERL_LIBS = case os:getenv("ERL_LIBS") of
-                   false ->
-                       {"ERL_LIBS", DepsDir};
-                   PrevValue ->
-                       {"ERL_LIBS", DepsDir ++ Separator ++ PrevValue}
-               end,
-    [{"REBAR_DEPS_DIR", DepsDir}, ERL_LIBS].
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
 
 -spec get_deps_dir(rebar_state:t()) -> file:filename_all().
 get_deps_dir(State) ->
     BaseDir = rebar_state:get(State, base_dir, ""),
-    get_deps_dir(BaseDir, "deps").
+    DepsDir = rebar_state:get(State, deps_dir, ?DEFAULT_DEPS_DIR),
+    get_deps_dir(BaseDir, DepsDir).
 
--spec get_deps_dir(file:filename_all(), rebar_state:t()) -> file:filename_all().
+-spec get_deps_dir(file:filename_all(), file:filename_all()) -> file:filename_all().
 get_deps_dir(DepsDir, App) ->
     filename:join(DepsDir, App).
 
-%% ===================================================================
-%% Internal functions
-%% ===================================================================
-
 -spec handle_deps(rebar_state:t(), [dep()]) -> {ok, rebar_state:t()}.
-handle_deps(State, []) ->
-    {ok, State};
 handle_deps(State, Deps) ->
+    handle_deps(State, Deps, false).
+
+-spec handle_deps(rebar_state:t(), [dep()], boolean() | {true, binary(), integer()})
+                 -> {ok, rebar_state:t()}.
+handle_deps(State, [], _) ->
+    {ok, State};
+handle_deps(State, Deps, Update) ->
     %% Read in package index and dep graph
     {Packages, Graph} = rebar_packages:get_packages(State),
-    ProjectApps = rebar_state:project_apps(State),
 
-    %% Split source deps form binary deps, needed to keep backwards compatibility
+    %% Split source deps from pkg deps, needed to keep backwards compatibility
     DepsDir = get_deps_dir(State),
-    {SrcDeps, BinaryDeps} = parse_deps(DepsDir, Deps),
-    State1 = rebar_state:src_deps(rebar_state:binary_deps(State, BinaryDeps),
+    {SrcDeps, PkgDeps} = parse_deps(DepsDir, Deps),
+    State1 = rebar_state:src_deps(rebar_state:pkg_deps(State, PkgDeps),
                                   SrcDeps),
 
     %% Fetch transitive src deps
-    State2 = update_src_deps(State1),
-    Solved = case rebar_state:binary_deps(State2) of
-                 [] -> %% No binary deps
-                     [];
-                 BinaryDeps1 ->
-                     %% Find binary deps needed
-                     {ok, S} = rlx_depsolver:solve(Graph, BinaryDeps1),
-                     %% Create app_info record for each binary dep
-                     lists:map(fun({Name, Vsn}) ->
-                                       AppInfo = package_to_app(DepsDir
-                                                               ,Packages
-                                                               ,Name
-                                                               ,Vsn),
-                                       ok = maybe_fetch(AppInfo),
-                                       AppInfo
-                               end, S)
+    State2 = update_src_deps(0, State1, Update),
+    Solved = case rebar_state:pkg_deps(State2) of
+                 [] -> %% No pkg deps
+                      [];
+                 PkgDeps1 ->
+                     %% Find pkg deps needed
+                     {ok, S} = rlx_depsolver:solve(Graph, PkgDeps1),
+                     %% Create app_info record for each pkg dep
+                     [AppInfo || Pkg <- S,
+                                 AppInfo <- package_to_app(DepsDir
+                                                          ,Packages
+                                                          ,Pkg),
+                                 maybe_fetch(AppInfo, Update)]
              end,
 
-    Source = ProjectApps ++ ordsets:to_list(rebar_state:src_deps(State2)),
-    AllDeps = ordsets:union([ordsets:to_list(rebar_state:src_deps(State2))
-                            ,ordsets:from_list(Solved)]),
-
+    AllDeps = lists:ukeymerge(2
+                            ,lists:ukeysort(2, rebar_state:src_apps(State2))
+                            ,lists:ukeysort(2, Solved)),
     %% Sort all apps to build order
     State3 = rebar_state:set(State2, all_deps, AllDeps),
-    {ok, Sort} = rebar_topo:sort_apps(ordsets:to_list(Source)),
-    {ok, rebar_state:set(State3, deps_to_build, lists:dropwhile(fun is_valid/1, Sort -- ProjectApps))}.
+    {ok, State3}.
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
 
--spec is_valid(rebar_app_info:t()) -> boolean().
-is_valid(App) ->
-    rebar_app_info:valid(App).
+package_to_app(DepsDir, Packages, Pkg={_, Vsn}) ->
+    Name = ec_cnv:to_binary(rlx_depsolver:dep_pkg(Pkg)),
+    FmtVsn = iolist_to_binary(rlx_depsolver:format_version(Vsn)),
+    case dict:find({Name, FmtVsn}, Packages) of
+        error ->
+            [];
+        {ok, P} ->
+            PkgDeps = proplists:get_value(<<"deps">>, P, []),
+            Link = proplists:get_value(<<"link">>, P, ""),
+            {ok, AppInfo} = rebar_app_info:new(Name, FmtVsn),
+            AppInfo1 = rebar_app_info:deps(AppInfo, PkgDeps),
+            AppInfo2 = rebar_app_info:dir(AppInfo1, get_deps_dir(DepsDir, Name)),
+            [rebar_app_info:source(AppInfo2, Link)]
+    end.
 
--spec package_to_app(file:name(), rlx_depsolver:t(), binary(), binary()) -> rebar_app_info:t().
-package_to_app(DepsDir, Packages, Name, Vsn) ->
-    FmtVsn = ec_cnv:to_binary(rlx_depsolver:format_version(Vsn)),
+-spec update_src_deps(integer(), rebar_state:t(), boolean()) -> rebar_state:t().
+update_src_deps(Level, State, Update) ->
+    SrcDeps = rebar_state:src_deps(State),
+    case lists:foldl(fun(AppInfo, {SrcDepsAcc, PkgDepsAcc, StateAcc}) ->
+                             case Update of
+                                 {true, UpdateName, UpdateLevel} ->
+                                     handle_update(AppInfo
+                                                  ,UpdateName
+                                                  ,UpdateLevel
+                                                  ,SrcDepsAcc
+                                                  ,PkgDepsAcc
+                                                  ,Level
+                                                  ,StateAcc);
+                                 _ ->
+                                     maybe_fetch(AppInfo, false),
+                                     handle_dep(AppInfo
+                                               ,SrcDepsAcc
+                                               ,PkgDepsAcc
+                                               ,Level
+                                               ,StateAcc)
+                             end
+                     end, {[], rebar_state:pkg_deps(State), State}, SrcDeps) of
+        {[], NewPkgDeps, State1} ->
+            rebar_state:pkg_deps(State1, NewPkgDeps);
+        {NewSrcDeps, NewPkgDeps, State1} ->
+            State2 = rebar_state:pkg_deps(State1, NewPkgDeps),
+            State3 = rebar_state:src_deps(State2, NewSrcDeps),
+            update_src_deps(Level+1, State3, Update)
+    end.
 
-    {ok, P} = dict:find({Name, FmtVsn}, Packages),
-    PkgDeps = proplists:get_value(<<"deps">>, P),
-    Link = proplists:get_value(<<"link">>, P),
+handle_update(AppInfo, UpdateName, UpdateLevel, SrcDeps, PkgDeps, Level, State) ->
+    Name = rebar_app_info:name(AppInfo),
+    Locks = rebar_state:get(State, locks, []),
+    {_, _, _, DepLevel} = lists:keyfind(Name, 1, Locks),
+    case UpdateLevel < DepLevel
+        orelse Name =:= UpdateName of
+        true ->
+            case maybe_fetch(AppInfo, true) of
+                true ->
+                    handle_dep(AppInfo
+                              ,SrcDeps
+                              ,PkgDeps
+                              ,Level
+                              ,State);
 
-    {ok, AppInfo} = rebar_app_info:new(Name, FmtVsn),
-    AppInfo1 = rebar_app_info:deps(AppInfo, PkgDeps),
-    AppInfo2 =
-        rebar_app_info:dir(AppInfo1, get_deps_dir(DepsDir, <<Name/binary, "-", FmtVsn/binary>>)),
-    rebar_app_info:source(AppInfo2, Link).
+                false ->
+                    {SrcDeps, PkgDeps, State}
+            end;
+        false ->
+            {SrcDeps, PkgDeps, State}
+    end.
 
--spec update_src_deps(rebar_state:t()) -> rebat_state:t().
-update_src_deps(State) ->
-    SrcDeps = rebar_state:src_deps(State),
+handle_dep(AppInfo, SrcDeps, PkgDeps, Level, State) ->
     DepsDir = get_deps_dir(State),
-    case lists:foldl(fun(AppInfo, {SrcDepsAcc, BinaryDepsAcc}) ->
-                             ok = maybe_fetch(AppInfo),
-                             {AppInfo1, NewSrcDeps, NewBinaryDeps} = handle_dep(DepsDir, AppInfo),
-                             {ordsets:union(ordsets:add_element(AppInfo1, SrcDepsAcc), NewSrcDeps)
-                             ,NewBinaryDeps++BinaryDepsAcc}
-                     end, {ordsets:new(), rebar_state:binary_deps(State)}, SrcDeps) of
-        {NewSrcDeps, NewBinaryDeps} when length(SrcDeps) =:= length(NewSrcDeps) ->
-            rebar_state:src_deps(rebar_state:binary_deps(State, NewBinaryDeps), NewSrcDeps);
-        {NewSrcDeps, NewBinaryDeps} ->
-            State1 = rebar_state:src_deps(rebar_state:binary_deps(State, NewBinaryDeps), NewSrcDeps),
-            update_src_deps(State1)
-    end.
+    {AppInfo1, NewSrcDeps, NewPkgDeps} =
+        handle_dep(DepsDir, AppInfo),
+    AppInfo2 = rebar_app_info:dep_level(AppInfo1, Level),
+    {NewSrcDeps ++ SrcDeps
+    ,NewPkgDeps++PkgDeps
+    ,rebar_state:src_apps(State, AppInfo2)}.
 
--spec handle_dep(binary(), rebar_state:t()) -> {[rebar_app_info:t()], [binary_dep()]}.
+-spec handle_dep(file:filename_all(), rebar_app_info:t()) ->
+                        {rebar_app_info:t(), [rebar_app_info:t()], [pkg_dep()]}.
 handle_dep(DepsDir, AppInfo) ->
     C = rebar_config:consult(rebar_app_info:dir(AppInfo)),
     S = rebar_state:new(rebar_state:new(), C, rebar_app_info:dir(AppInfo)),
     Deps = rebar_state:get(S, deps, []),
     AppInfo1 = rebar_app_info:deps(AppInfo, rebar_state:deps_names(S)),
-    {SrcDeps, BinaryDeps} = parse_deps(DepsDir, Deps),
-    {AppInfo1, SrcDeps, BinaryDeps}.
+    {SrcDeps, PkgDeps} = parse_deps(DepsDir, Deps),
+    {AppInfo1, SrcDeps, PkgDeps}.
 
--spec maybe_fetch(rebar_app_info:t()) -> ok.
-maybe_fetch(AppInfo) ->
-    AppDir = rebar_app_info:dir(AppInfo),
-    case filelib:is_dir(AppDir) of
-        false ->
-            ?INFO("Fetching ~s~n", [rebar_app_info:name(AppInfo)]),
-            Source = rebar_app_info:source(AppInfo),
-            rebar_fetch:download_source(AppDir, Source);
-        true ->
-            ok
+-spec maybe_fetch(rebar_app_info:t(), boolean() | {true, binary(), integer()}) -> boolean().
+maybe_fetch(AppInfo, Update) ->
+    AppDir = ec_cnv:to_list(rebar_app_info:dir(AppInfo)),
+    Apps = rebar_app_discover:find_apps(["_checkouts"], all),
+    case rebar_app_utils:find(rebar_app_info:name(AppInfo), Apps) of
+        {ok, _} ->
+            %% Don't fetch dep if it exists in the _checkouts dir
+            false;
+        error ->
+            Exists = case rebar_app_utils:is_app_dir(filename:absname(AppDir)++"-*") of
+                         {true, _} ->
+                             true;
+                         _ ->
+                             case rebar_app_utils:is_app_dir(filename:absname(AppDir)) of
+                                 {true, _} ->
+                                     true;
+                                 _ ->
+                                     false
+                             end
+                     end,
+
+            case not Exists orelse Update of
+                true ->
+                    ?INFO("Fetching ~s~n", [rebar_app_info:name(AppInfo)]),
+                    Source = rebar_app_info:source(AppInfo),
+                    rebar_fetch:download_source(AppDir, Source),
+                    true;
+                _ ->
+                    false
+            end
     end.
 
--spec parse_deps(binary(), [dep()]) -> {ordsets:ordset(rebar_app_info:t()), [binary_dep()]}.
+-spec parse_deps(binary(), [dep()]) -> {[rebar_app_info:t()], [pkg_dep()]}.
 parse_deps(DepsDir, Deps) ->
-    lists:foldl(fun({Name, Vsn}, {SrcDepsAcc, BinaryDepsAcc}) ->
+    lists:foldl(fun({Name, Vsn}, {SrcDepsAcc, PkgDepsAcc}) ->
                         {SrcDepsAcc, [parse_goal(ec_cnv:to_binary(Name)
-                                                ,ec_cnv:to_binary(Vsn)) | BinaryDepsAcc]};
-                   (Name, {SrcDepsAcc, BinaryDepsAcc}) when is_atom(Name) ->
-                        {SrcDepsAcc, [ec_cnv:to_binary(Name) | BinaryDepsAcc]};
-                   ({Name, Vsn, Source}, {SrcDepsAcc, BinaryDepsAcc}) when is_tuple (Source) ->
-                        Dir = ec_cnv:to_list(get_deps_dir(DepsDir, Name)),
-                        {ok, Dep} = case rebar_app_info:discover(Dir) of
-                                        {ok, App} ->
-                                            {ok, App};
-                                        not_found ->
-                                            rebar_app_info:new(Name, Vsn, Dir)
-                                    end,
-                        Dep1 = rebar_app_info:source(Dep, Source),
-                        {ordsets:add_element(Dep1, SrcDepsAcc), BinaryDepsAcc}
-                end, {ordsets:new(), []}, Deps).
-
--spec parse_goal(binary(), binary()) -> binary_dep().
+                                                ,ec_cnv:to_binary(Vsn)) | PkgDepsAcc]};
+                   (Name, {SrcDepsAcc, PkgDepsAcc}) when is_atom(Name) ->
+                        {SrcDepsAcc, [ec_cnv:to_binary(Name) | PkgDepsAcc]};
+                   ({Name, Vsn, Source}, {SrcDepsAcc, PkgDepsAcc}) when is_tuple (Source) ->
+                        Dep = new_dep(DepsDir, Name, Vsn, Source),
+                        {[Dep | SrcDepsAcc], PkgDepsAcc};
+                   ({Name, Vsn, Source, _Level}, {SrcDepsAcc, PkgDepsAcc}) when is_tuple (Source) ->
+                        Dep = new_dep(DepsDir, Name, Vsn, Source),
+                        {[Dep | SrcDepsAcc], PkgDepsAcc}
+                end, {[], []}, Deps).
+
+new_dep(DepsDir, Name, Vsn, Source) ->
+    Dir = ec_cnv:to_list(get_deps_dir(DepsDir, Name)),
+    {ok, Dep} = case rebar_app_info:discover(Dir) of
+                    {ok, App} ->
+                        {ok, App};
+                    not_found ->
+                        rebar_app_info:new(Name, Vsn, Dir)
+                end,
+    rebar_app_info:source(Dep, Source).
+
+-spec parse_goal(binary(), binary()) -> pkg_dep().
 parse_goal(Name, Constraint) ->
     case re:run(Constraint, "([^\\d]*)(\\d.*)", [{capture, [1,2], binary}]) of
         {match, [<<>>, Vsn]} ->
@@ -236,9 +301,7 @@ info(Description) ->
                  "~n"
                  "Valid rebar.config options:~n"
                  "  ~p~n"
-                 "  ~p~n"
-                 "Valid command line options:~n"
-                 "  deps_dir=\"deps\" (override default or rebar.config deps_dir)~n",
+                 "  ~p~n",
                  [
                  Description,
                  {deps_dir, "deps"},
diff --git a/src/rebar_prv_lock.erl b/src/rebar_prv_lock.erl
index b4a7d8d..32c5f1a 100644
--- a/src/rebar_prv_lock.erl
+++ b/src/rebar_prv_lock.erl
@@ -1,9 +1,10 @@
 -module(rebar_prv_lock).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -16,17 +17,17 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = true,
-                                                       deps = ?DEPS,
-                                                       example = "",
-                                                       short_desc = "Locks dependencies.",
-                                                       desc = info("Locks dependencies"),
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, true},
+                                                               {deps, ?DEPS},
+                                                               {example, ""},
+                                                               {short_desc, "Locks dependencies."},
+                                                               {desc, info("Locks dependencies")},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     case rebar_state:get(State, locks, []) of
         [] ->
@@ -40,7 +41,8 @@ do(State) ->
                                           Source when is_tuple(Source) ->
                                               {rebar_app_info:name(Dep)
                                               ,rebar_app_info:original_vsn(Dep)
-                                              ,rebar_fetch:lock_source(Dir, Source)};
+                                              ,rebar_fetch:lock_source(Dir, Source)
+                                              ,rebar_app_info:dep_level(Dep)};
                                           _Source ->
                                               {rebar_app_info:name(Dep)
                                               ,rebar_app_info:original_vsn(Dep)}
@@ -53,5 +55,9 @@ do(State) ->
             {ok, State}
     end.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
 info(_) ->
     "".
diff --git a/src/rebar_prv_new.erl b/src/rebar_prv_new.erl
index ed3c1b4..2555b4d 100644
--- a/src/rebar_prv_new.erl
+++ b/src/rebar_prv_new.erl
@@ -1,9 +1,10 @@
 -module(rebar_prv_new).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -16,17 +17,17 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar new <template>",
-                                                       short_desc = "Create new project from templates.",
-                                                       desc = info(create),
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar new <template>"},
+                                                               {short_desc, "Create new project from templates."},
+                                                               {desc, info()},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     case rebar_state:command_args(State) of
         [TemplateName] ->
@@ -41,33 +42,17 @@ do(State) ->
             {ok, State}
     end.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
 %% ===================================================================
 %% Internal functions
 %% ===================================================================
 
-info(create) ->
-    io_lib:format(
-       "Create skel based on template and vars.~n"
-       "~n"
-       "Valid command line options:~n"
-       "  template= [var=foo,...]~n", []);
-info(create_app) ->
-    io_lib:format(
-       "Create simple app skel.~n"
-       "~n"
-       "Valid command line options:~n"
-       "  [appid=myapp]~n", []);
-info(create_lib) ->
-    io_lib:format(
-       "Create simple lib skel.~n"
-       "~n"
-       "Valid command line options:~n"
-       "  [libid=mylib]~n", []);
-info(create_node) ->
+info() ->
     io_lib:format(
-       "Create simple node skel.~n"
-       "~n"
-       "Valid command line options:~n"
-       "  [nodeid=mynode]~n", []);
-info(list_templates) ->
-    io_lib:format("List available templates.~n", []).
+      "Create rebar project based on template and vars.~n"
+      "~n"
+      "Valid command line options:~n"
+      "  template= [var=foo,...]~n", []).
diff --git a/src/rebar_prv_packages.erl b/src/rebar_prv_packages.erl
index 79c1cd2..be51833 100644
--- a/src/rebar_prv_packages.erl
+++ b/src/rebar_prv_packages.erl
@@ -1,9 +1,10 @@
 -module(rebar_prv_packages).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -12,22 +13,26 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar pkgs",
-                                                       short_desc = "List available packages.",
-                                                       desc = info("List available packages"),
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar pkgs"},
+                                                               {short_desc, "List available packages."},
+                                                               {desc, info("List available packages")},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     {Packages, _Graph} = rebar_packages:get_packages(State),
     print_packages(Packages),
     {ok, State}.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
 print_packages(Packages) ->
     Keys = lists:keysort(1, dict:fetch_keys(Packages)),
     Pkgs = merge(Keys),
diff --git a/src/rebar_prv_release.erl b/src/rebar_prv_release.erl
index 4203c3a..572f909 100644
--- a/src/rebar_prv_release.erl
+++ b/src/rebar_prv_release.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_release).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,17 +20,28 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar release",
-                                                       short_desc = "Build release of project.",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar release"},
+                                                               {short_desc, "Build release of project."},
+                                                               {desc, ""},
+                                                               {opts, relx:opt_spec_list()}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
-do(Config) ->
-    relx:main("release"),
-    {ok, Config}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+    Options = rebar_state:command_args(State),
+    AllOptions = string:join(["release" | Options], " "),
+    case rebar_state:get(State, relx, []) of
+        [] ->
+            relx:main(AllOptions);
+        Config ->
+            relx:main([{config, Config}], AllOptions)
+    end,
+    {ok, State}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
diff --git a/src/rebar_prv_shell.erl b/src/rebar_prv_shell.erl
index 80f6bcf..24e357b 100644
--- a/src/rebar_prv_shell.erl
+++ b/src/rebar_prv_shell.erl
@@ -28,10 +28,11 @@
 -module(rebar_prv_shell).
 -author("Kresten Krab Thorup <krab@trifork.com>").
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -44,21 +45,25 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                        provider_impl = ?MODULE,
-                                                        bare = false,
-                                                        deps = ?DEPS,
-                                                        example = "rebar shell",
-                                                        short_desc = "Run shell with project apps and deps in path.",
-                                                        desc = info(),
-                                                        opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar shell"},
+                                                               {short_desc, "Run shell with project apps and deps in path."},
+                                                               {desc, info()},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(Config) ->
     shell(),
     {ok, Config}.
 
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
 %% NOTE:
 %% this is an attempt to replicate `erl -pa ./ebin -pa deps/*/ebin`. it is
 %% mostly successful but does stop and then restart the user io system to get
diff --git a/src/rebar_prv_tar.erl b/src/rebar_prv_tar.erl
index 7f5ab4f..04a1b33 100644
--- a/src/rebar_prv_tar.erl
+++ b/src/rebar_prv_tar.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_tar).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,17 +20,26 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                        provider_impl = ?MODULE,
-                                                        bare = false,
-                                                        deps = ?DEPS,
-                                                        example = "rebar tar",
-                                                        short_desc = "Tar archive of release built of project.",
-                                                        desc = "",
-                                                        opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar tar"},
+                                                               {short_desc, "Tar archive of release built of project."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
-do(Config) ->
-    relx:main("release tar"),
-    {ok, Config}.
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+    case rebar_state:get(State, relx, []) of
+        [] ->
+            relx:main(["release tar"]);
+        Config ->
+            relx:main([{config, Config}], ["release tar"])
+    end,
+    {ok, State}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
diff --git a/src/rebar_prv_test_deps.erl b/src/rebar_prv_test_deps.erl
new file mode 100644
index 0000000..081b210
--- /dev/null
+++ b/src/rebar_prv_test_deps.erl
@@ -0,0 +1,63 @@
+-module(rebar_prv_test_deps).
+
+-behaviour(provider).
+
+-export([init/1,
+         do/1,
+         format_error/2]).
+
+-include("rebar.hrl").
+
+-define(PROVIDER, test_deps).
+-define(DEPS, [install_deps]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
+init(State) ->
+    Providers = rebar_state:providers(State),
+    CompileProvider = providers:get_provider(compile, Providers),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, true},
+                                                               {deps, ?DEPS},
+                                                               {hooks, {[], [CompileProvider]}},
+                                                               {example, undefined},
+                                                               {short_desc, "Install dependencies needed only for testing."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
+    {ok, State1}.
+
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+    ProjectApps = rebar_state:project_apps(State),
+    TestDeps = rebar_state:get(State, test_deps, []),
+    Names = [ec_cnv:to_binary(element(1, Dep)) || Dep <- TestDeps],
+    ProjectApps1 = [rebar_app_info:deps(A, Names) || A <- ProjectApps],
+
+    {ok, State1} = rebar_prv_install_deps:handle_deps(State, TestDeps),
+    AllDeps = rebar_state:get(State1, all_deps, []),
+
+    case rebar_topo:sort_apps(ProjectApps1++AllDeps) of
+        {ok, Sort} ->
+            _ToBuild = lists:dropwhile(fun rebar_app_info:valid/1, Sort),
+            %% lists:foreach(fun(AppInfo) ->
+            %%                       AppDir = rebar_app_info:dir(AppInfo),
+            %%                       C = rebar_config:consult(AppDir),
+            %%                       S = rebar_state:new(State1, C, AppDir),
+            %%                       rebar_prv_compile:build(S, AppInfo)
+            %%               end, ToBuild),
+            {ok, State1};
+        {error, Error} ->
+            {error, Error}
+    end.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
diff --git a/src/rebar_prv_update.erl b/src/rebar_prv_update.erl
index e19041a..0d388c8 100644
--- a/src/rebar_prv_update.erl
+++ b/src/rebar_prv_update.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_update).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,41 +20,35 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar update cowboy",
-                                                       short_desc = "Update package index or individual dependency.",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar update"},
+                                                               {short_desc, "Update package index."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
-    case rebar_state:command_args(State) of
-        [Name] ->
-            ?ERROR("NOT IMPLEMENTED: Updating ~s~n", [Name]),
-            {ok, State};
-        [] ->
-            ?INFO("Updating package index...~n", []),
-            Url = url(State),
-            %{ok, [Home]} = init:get_argument(home),
-            ec_file:mkdir_p(filename:join([os:getenv("HOME"), ".rebar"])),
-            PackagesFile = filename:join([os:getenv("HOME"), ".rebar", "packages"]),
-            {ok, RequestId} = httpc:request(get, {Url, []}, [], [{stream, PackagesFile}, {sync, false}]),
-            wait(RequestId, State)
-    end.
-
-wait(RequestId, State) ->
-    receive
-        {http, {RequestId, saved_to_file}} ->
-            {ok, State}
-    after
-        500 ->
-            io:format("."),
-            wait(RequestId, State)
-    end.
+    ?INFO("Updating package index...~n", []),
+    try
+        Url = url(State),
+                                                %{ok, [Home]} = init:get_argument(home),
+        ec_file:mkdir_p(filename:join([os:getenv("HOME"), ".rebar"])),
+        PackagesFile = filename:join([os:getenv("HOME"), ".rebar", "packages"]),
+        {ok, _RequestId} = httpc:request(get, {Url, []}, [], [{stream, PackagesFile}
+                                                             ,{sync, true}])
+    catch
+        _:_ ->
+            {error, io_lib:format("Failed to write package index.~n", [])}
+    end,
+    {ok, State}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
 
 url(State) ->
     SystemArch = erlang:system_info(system_architecture),
diff --git a/src/rebar_prv_upgrade.erl b/src/rebar_prv_upgrade.erl
new file mode 100644
index 0000000..1668e1c
--- /dev/null
+++ b/src/rebar_prv_upgrade.erl
@@ -0,0 +1,55 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+
+-module(rebar_prv_upgrade).
+
+-behaviour(provider).
+
+-export([init/1,
+         do/1,
+         format_error/2]).
+
+-include("rebar.hrl").
+
+-define(PROVIDER, upgrade).
+-define(DEPS, [lock]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
+init(State) ->
+    State1 =
+        rebar_state:add_provider(State,
+                                 providers:create([{name, ?PROVIDER},
+                                                   {module, ?MODULE},
+                                                   {bare, false},
+                                                   {deps, ?DEPS},
+                                                   {example, "rebar upgrade cowboy"},
+                                                   {short_desc, "Upgrade dependency."},
+                                                   {desc, ""},
+                                                   {opts, [
+                                                          {package, undefined, undefined, string, "Package to upgrade."}
+                                                          ]}])),
+    {ok, State1}.
+
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+    {Args, _} = rebar_state:command_parsed_args(State),
+    Name = proplists:get_value(package, Args),
+    ?INFO("Updating ~s~n", [Name]),
+    Locks = rebar_state:get(State, locks, []),
+    case lists:keyfind(ec_cnv:to_binary(Name), 1, Locks) of
+        {_, _, _, Level} ->
+            Deps = rebar_state:get(State, deps),
+            Dep = lists:keyfind(list_to_atom(Name), 1, Deps),
+            rebar_prv_install_deps:handle_deps(State, [Dep], {true, ec_cnv:to_binary(Name), Level}),
+            {ok, State};
+        _ ->
+            {error, io_lib:format("No such dependency ~s~n", [Name])}
+    end.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
diff --git a/src/rebar_prv_version.erl b/src/rebar_prv_version.erl
index 9197438..1e907d1 100644
--- a/src/rebar_prv_version.erl
+++ b/src/rebar_prv_version.erl
@@ -3,10 +3,11 @@
 
 -module(rebar_prv_version).
 
--behaviour(rebar_provider).
+-behaviour(provider).
 
 -export([init/1,
-         do/1]).
+         do/1,
+         format_error/2]).
 
 -include("rebar.hrl").
 
@@ -19,18 +20,22 @@
 
 -spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
 init(State) ->
-    State1 = rebar_state:add_provider(State, #provider{name = ?PROVIDER,
-                                                       provider_impl = ?MODULE,
-                                                       bare = false,
-                                                       deps = ?DEPS,
-                                                       example = "rebar version",
-                                                       short_desc = "Print version for rebar and current Erlang.",
-                                                       desc = "",
-                                                       opts = []}),
+    State1 = rebar_state:add_provider(State, providers:create([{name, ?PROVIDER},
+                                                               {module, ?MODULE},
+                                                               {bare, false},
+                                                               {deps, ?DEPS},
+                                                               {example, "rebar version"},
+                                                               {short_desc, "Print version for rebar and current Erlang."},
+                                                               {desc, ""},
+                                                               {opts, []}])),
 
     {ok, State1}.
 
--spec do(rebar_state:t()) -> {ok, rebar_state:t()} | relx:error().
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     rebar3:version(),
     {ok, State}.
+
+-spec format_error(any(), rebar_state:t()) ->  {iolist(), rebar_state:t()}.
+format_error(Reason, State) ->
+    {io_lib:format("~p", [Reason]), State}.
diff --git a/src/rebar_state.erl b/src/rebar_state.erl
index 706c528..f39251d 100644
--- a/src/rebar_state.erl
+++ b/src/rebar_state.erl
@@ -3,49 +3,39 @@
 -export([new/0, new/1, new/2, new/3,
          get/2, get/3, set/3,
          command_args/1, command_args/2,
+         command_parsed_args/1, command_parsed_args/2,
 
          dir/1, dir/2,
-         set_skip_dir/2, is_skip_dir/2, reset_skip_dirs/1,
          create_logic_providers/2,
 
          project_apps/1, project_apps/2,
 
          deps_names/1,
-         binary_deps/1, binary_deps/2,
+         pkg_deps/1, pkg_deps/2,
          src_deps/1, src_deps/2,
+         src_apps/1, src_apps/2,
 
          prepend_hook/3, append_hook/3, hooks/2,
          providers/1, providers/2, add_provider/2]).
 
 -include("rebar.hrl").
 
--ifdef(namespaced_types).
-%% dict:dict() exists starting from Erlang 17.
--type rebar_dict() :: dict:dict(term(), term()).
--else.
-%% dict() has been obsoleted in Erlang 17 and deprecated in 18.
--type rebar_dict() :: dict().
--endif.
+-record(state_t, {dir :: file:name(),
+                  opts = [],
 
--record(state_t, {dir :: file:filename(),
-                  opts = [] :: list(),
-                  local_opts = [] :: list(),
-                  config = new_globals() :: rebar_dict(),
+                  command_args = [],
+                  command_parsed_args = [],
 
-                  envs = new_env() :: rebar_dict(),
-                  command_args = [] :: list(),
+                  src_deps = [],
+                  src_apps = [],
+                  pkg_deps = [] :: [rlx_depsolver:constraint()],
+                  project_apps = [],
 
-                  src_deps = ordsets:new() :: ordsets:ordset(rebar_app_info:t()),
-                  binary_deps = [],
-                  project_apps = ordsets:new() :: ordsets:ordset(rebar_app_info:t()),
-
-                  providers = [],
-                  hooks = [],
-                  skip_dirs = new_skip_dirs() :: rebar_dict() }).
+                  providers = []}).
 
 -export_type([t/0]).
 
--opaque t() :: #state_t{}.
+-type t() :: record(state_t).
 
 -spec new() -> t().
 new() ->
@@ -64,9 +54,9 @@ new(ParentState=#state_t{}, Config) ->
 
 -spec new(t(), list(), file:name()) -> t().
 new(ParentState, Config, Dir) ->
-    _Opts = ParentState#state_t.opts,
+    Opts = ParentState#state_t.opts,
     LocalOpts = case rebar_config:consult_file(?LOCK_FILE) of
-                    {ok, [D]} ->
+                    [D] ->
                         [{locks, D} | Config];
                     _ ->
                         Config
@@ -74,7 +64,7 @@ new(ParentState, Config, Dir) ->
 
     ProviderModules = [],
     create_logic_providers(ProviderModules, ParentState#state_t{dir=Dir
-                                                               ,opts=LocalOpts}).
+                                                               ,opts=lists:umerge(LocalOpts, Opts)}).
 
 get(State, Key) ->
     proplists:get_value(Key, State#state_t.opts).
@@ -82,33 +72,23 @@ get(State, Key) ->
 get(State, Key, Default) ->
     proplists:get_value(Key, State#state_t.opts, Default).
 
+-spec set(t(), any(), any()) -> t().
 set(State, Key, Value) ->
     Opts = proplists:delete(Key, State#state_t.opts),
     State#state_t { opts = [{Key, Value} | Opts] }.
 
-set_skip_dir(State, Dir) ->
-    OldSkipDirs = State#state_t.skip_dirs,
-    NewSkipDirs = case is_skip_dir(State, Dir) of
-                      false ->
-                          ?DEBUG("Adding skip dir: ~s\n", [Dir]),
-                          dict:store(Dir, true, OldSkipDirs);
-                      true ->
-                          OldSkipDirs
-                  end,
-    State#state_t{skip_dirs = NewSkipDirs}.
-
-is_skip_dir(State, Dir) ->
-    dict:is_key(Dir, State#state_t.skip_dirs).
-
-reset_skip_dirs(State) ->
-    State#state_t{skip_dirs = new_skip_dirs()}.
-
 command_args(#state_t{command_args=CmdArgs}) ->
     CmdArgs.
 
 command_args(State, CmdArgs) ->
     State#state_t{command_args=CmdArgs}.
 
+command_parsed_args(#state_t{command_parsed_args=CmdArgs}) ->
+    CmdArgs.
+
+command_parsed_args(State, CmdArgs) ->
+    State#state_t{command_parsed_args=CmdArgs}.
+
 dir(#state_t{dir=Dir}) ->
     Dir.
 
@@ -123,13 +103,14 @@ deps_names(State) ->
                       ec_cnv:to_binary(Dep)
               end, Deps).
 
-binary_deps(#state_t{binary_deps=BinaryDeps}) ->
-    BinaryDeps.
+-spec pkg_deps(t()) -> [rlx_depsolver:constraint()].
+pkg_deps(#state_t{pkg_deps=PkgDeps}) ->
+    PkgDeps.
 
-binary_deps(State=#state_t{binary_deps=BinaryDeps}, NewBinaryDeps) when is_list(BinaryDeps) ->
-    State#state_t{binary_deps=NewBinaryDeps};
-binary_deps(State=#state_t{binary_deps=BinaryDeps}, BinaryDep) ->
-    State#state_t{binary_deps=[BinaryDep | BinaryDeps]}.
+pkg_deps(State=#state_t{pkg_deps=PkgDeps}, NewPkgDeps) when is_list(PkgDeps) ->
+    State#state_t{pkg_deps=NewPkgDeps};
+pkg_deps(State=#state_t{pkg_deps=PkgDeps}, PkgDep) ->
+    State#state_t{pkg_deps=[PkgDep | PkgDeps]}.
 
 src_deps(#state_t{src_deps=SrcDeps}) ->
     SrcDeps.
@@ -137,7 +118,19 @@ src_deps(#state_t{src_deps=SrcDeps}) ->
 src_deps(State=#state_t{src_deps=SrcDeps}, NewSrcDeps) when is_list(SrcDeps) ->
     State#state_t{src_deps=NewSrcDeps};
 src_deps(State=#state_t{src_deps=SrcDeps}, SrcDep) ->
-    State#state_t{src_deps=[SrcDep | SrcDeps]}.
+    Name = rebar_app_info:name(SrcDep),
+    NewSrcDeps = lists:keystore(Name, 2, SrcDeps, SrcDep),
+    State#state_t{src_deps=NewSrcDeps}.
+
+src_apps(#state_t{src_apps=SrcApps}) ->
+    SrcApps.
+
+src_apps(State=#state_t{src_apps=_SrcApps}, NewSrcApps) when is_list(NewSrcApps) ->
+    State#state_t{src_apps=NewSrcApps};
+src_apps(State=#state_t{src_apps=SrcApps}, NewSrcApp) ->
+    Name = rebar_app_info:name(NewSrcApp),
+    NewSrcApps = lists:keystore(Name, 2, SrcApps, NewSrcApp),
+    State#state_t{src_apps=NewSrcApps}.
 
 project_apps(#state_t{project_apps=Apps}) ->
     Apps.
@@ -153,32 +146,44 @@ providers(#state_t{providers=Providers}) ->
 providers(State, NewProviders) ->
     State#state_t{providers=NewProviders}.
 
+-spec add_provider(t(), providers:t()) -> t().
 add_provider(State=#state_t{providers=Providers}, Provider) ->
     State#state_t{providers=[Provider | Providers]}.
 
 create_logic_providers(ProviderModules, State0) ->
     lists:foldl(fun(ProviderMod, Acc) ->
-                        {ok, State1} = rebar_provider:new(ProviderMod, Acc),
-                        State1
+                        case providers:new(ProviderMod, Acc) of
+                            {error, Reason} ->
+                                ?ERROR(Reason++"~n", []),
+                                Acc;
+                            {ok, State1} ->
+                                State1
+                        end
                 end, State0, ProviderModules).
 
-prepend_hook(State=#state_t{hooks=Hooks}, Target, Hook) ->
-    {PreHooks, PostHooks} = proplists:get_value(Target, Hooks, {[], []}),
-    State#state_t{hooks=[{Target, {[Hook | PreHooks], PostHooks}} | proplists:delete(Target, Hooks)]}.
+prepend_hook(State=#state_t{providers=Providers}, Target, Hook) ->
+    State#state_t{providers=add_hook(pre, Providers, Target, Hook)}.
 
-append_hook(State=#state_t{hooks=Hooks}, Target, Hook) ->
-    {PreHooks, PostHooks} = proplists:get_value(Target, Hooks, {[], []}),
-    State#state_t{hooks=[{Target, {PreHooks, [Hook | PostHooks]}} | proplists:delete(Target, Hooks)]}.
+append_hook(State=#state_t{providers=Providers}, Target, Hook) ->
+    State#state_t{providers=add_hook(post, Providers, Target, Hook)}.
 
-hooks(#state_t{hooks=Hooks}, Target) ->
-    proplists:get_value(Target, Hooks, {[], []}).
+-spec hooks(t(), atom()) -> {[providers:t()], [providers:t()]}.
+hooks(_State=#state_t{providers=Providers}, Target) ->
+    Provider = providers:get_provider(Target, Providers),
+    providers:hooks(Provider).
 
 %% ===================================================================
 %% Internal functions
 %% ===================================================================
 
-new_globals() -> dict:new().
-
-new_env() -> dict:new().
-
-new_skip_dirs() -> dict:new().
+add_hook(Which, Providers, Target, Hook) ->
+    Provider = providers:get_provider(Target, Providers),
+    Hooks = providers:hooks(Provider),
+    NewHooks = add_hook(Which, Hooks, Hook),
+    NewProvider = providers:hooks(Provider, NewHooks),
+    [NewProvider | lists:delete(Provider, Providers)].
+
+add_hook(pre, {PreHooks, PostHooks}, Hook) ->
+    {[Hook | PreHooks], PostHooks};
+add_hook(post, {PreHooks, PostHooks}, Hook) ->
+    {PreHooks, [Hook | PostHooks]}.
diff --git a/src/rebar_templater.erl b/src/rebar_templater.erl
index a795b66..b30c517 100644
--- a/src/rebar_templater.erl
+++ b/src/rebar_templater.erl
@@ -47,6 +47,8 @@ new(app, DirName, State) ->
     create1(State, DirName, "otp_app");
 new(lib, DirName, State) ->
     create1(State, DirName, "otp_lib");
+new(plugin, DirName, State) ->
+    create1(State, DirName, "plugin");
 new(rel, DirName, State) ->
     create1(State, DirName, "otp_rel").
 
@@ -78,7 +80,7 @@ create(State) ->
 resolve_variables([], Dict) ->
     Dict;
 resolve_variables([{Key, Value0} | Rest], Dict) when is_list(Value0) ->
-    Value = render(list_to_binary(Value0), Dict),
+    Value = render(Value0, Dict),
     resolve_variables(Rest, dict:store(Key, Value, Dict));
 resolve_variables([{Key, {list, Dicts}} | Rest], Dict) when is_list(Dicts) ->
     %% just un-tag it so erlydtl can use it
@@ -376,7 +378,7 @@ execute_template(Files, [{'case', Variable, Values, Instructions} | Rest], Templ
                      ExistingFiles);
 execute_template(Files, [{template, Input, Output} | Rest], TemplateType,
                  TemplateName, Context, Force, ExistingFiles) ->
-    InputName = filename:join(filename:dirname(TemplateName), Input),
+    _InputName = filename:join(filename:dirname(TemplateName), Input),
     %File = load_file(Files, TemplateType, InputName),
     OutputTemplateName = make_template_name("rebar_output_template", Output),
     {ok, OutputTemplateName1} = erlydtl:compile_template(Output, OutputTemplateName, ?ERLYDTL_COMPILE_OPTS),
diff --git a/src/rebar_topo.erl b/src/rebar_topo.erl
index 87ee234..de3351a 100644
--- a/src/rebar_topo.erl
+++ b/src/rebar_topo.erl
@@ -54,20 +54,18 @@
 %% applications. This implies that you have already done the
 %% constraint solve before you pass the list of apps here to be
 %% sorted.
--spec sort_apps([rebar_app_info:t()]) ->
-                       {ok, [rebar_app_info:t()]} |
-                       relx:error().
+-spec sort_apps([rebar_app_info:t()]) -> {ok, [rebar_app_info:t()]} | {error, any()}.
 sort_apps(Apps) ->
     Pairs = apps_to_pairs(Apps),
     case sort(Pairs) of
         {ok, Names} ->
             {ok, names_to_apps(Names, Apps)};
         E ->
-            E
+            {error, E}
     end.
 
 %% @doc Do a topological sort on the list of pairs.
--spec sort([pair()]) -> {ok, [atom()]} | relx:error().
+-spec sort([pair()]) -> {ok, [atom()]} | {error, any()}.
 sort(Pairs) ->
     iterate(Pairs, [], all(Pairs)).
 
@@ -78,9 +76,9 @@ format_error({cycle, Pairs}) ->
      "before we can continue:\n",
     case Pairs of
         [{P1, P2}] ->
-            [rebar_util:indent(2), erlang:atom_to_list(P2), "->", erlang:atom_to_list(P1)];
+            [rebar_utils:indent(2), erlang:atom_to_list(P2), "->", erlang:atom_to_list(P1)];
         [{P1, P2} | Rest] ->
-            [rebar_util:indent(2), erlang:atom_to_list(P2), "->", erlang:atom_to_list(P1),
+            [rebar_utils:indent(2), erlang:atom_to_list(P2), "->", erlang:atom_to_list(P1),
              [["-> ", erlang:atom_to_list(PP2), " -> ", erlang:atom_to_list(PP1)] || {PP1, PP2} <- Rest]];
         [] ->
             []
@@ -91,12 +89,12 @@ format_error({cycle, Pairs}) ->
 %%====================================================================
 -spec names_to_apps([atom()], [rebar_app_info:t()]) -> [rebar_app_info:t()].
 names_to_apps(Names, Apps) ->
- [element(2, App) || App <- [find_app_by_name(Name, Apps) || Name <- Names], App =/= error].
+    [element(2, App) || App <- [find_app_by_name(Name, Apps) || Name <- Names], App =/= error].
 
 -spec find_app_by_name(atom(), [rebar_app_info:t()]) -> {ok, rebar_app_info:t()} | error.
 find_app_by_name(Name, Apps) ->
     ec_lists:find(fun(App) ->
-                          rebar_app_info:name(App) =:= Name
+                          ec_cnv:to_atom(rebar_app_info:name(App)) =:= ec_cnv:to_atom(Name)
                   end, Apps).
 
 -spec apps_to_pairs([rebar_app_info:t()]) -> [pair()].
@@ -105,20 +103,20 @@ apps_to_pairs(Apps) ->
 
 -spec app_to_pairs(rebar_app_info:t()) -> [pair()].
 app_to_pairs(App) ->
-    [{DepApp, rebar_app_info:name(App)} ||
+    [{ec_cnv:to_atom(DepApp), ec_cnv:to_atom(rebar_app_info:name(App))} ||
         DepApp <-
             rebar_app_info:deps(App)].
 
 
 %% @doc Iterate over the system.  @private
 -spec iterate([pair()], [name()], [name()]) ->
-    {ok, [name()]} | relx:error().
+    {ok, [name()]} | {error, iolist()}.
 iterate([], L, All) ->
     {ok, remove_duplicates(L ++ subtract(All, L))};
 iterate(Pairs, L, All) ->
     case subtract(lhs(Pairs), rhs(Pairs)) of
         []  ->
-            ?ERROR(format_error({cycle, Pairs}), []);
+            {error, format_error({cycle, Pairs})};
         Lhs ->
             iterate(remove_pairs(Lhs, Pairs), L ++ Lhs, All)
     end.
@@ -188,29 +186,27 @@ topo_2_test() ->
 
 topo_pairs_cycle_test() ->
     Pairs = [{app2, app1}, {app1, app2}, {stdlib, app1}],
-    ?assertMatch({error, {_, {cycle, [{app2, app1}, {app1, app2}]}}},
-                 sort(Pairs)).
+    ?assertMatch({error, _}, sort(Pairs)).
 
 topo_apps_cycle_test() ->
-    {ok, App1} = rebar_app_info:new(app1, "0.1", "/no-dir", [app2], [stdlib]),
-    {ok, App2} = rebar_app_info:new(app2, "0.1", "/no-dir", [app1], []),
+    {ok, App1} = rebar_app_info:new(app1, "0.1", "/no-dir", [app2]),
+    {ok, App2} = rebar_app_info:new(app2, "0.1", "/no-dir", [app1]),
     Apps = [App1, App2],
-    ?assertMatch({error, {_, {cycle, [{app2,app1},{app1,app2}]}}},
-                 sort_apps(Apps)).
+    ?assertMatch({error, _}, sort_apps(Apps)).
 
 topo_apps_good_test() ->
     Apps = [App ||
                {ok, App} <-
-                   [rebar_app_info:new(app1, "0.1", "/no-dir", [app2, zapp1], [stdlib, kernel]),
-                    rebar_app_info:new(app2, "0.1", "/no-dir", [app3], []),
-                    rebar_app_info:new(app3, "0.1", "/no-dir", [kernel], []),
-                    rebar_app_info:new(zapp1, "0.1", "/no-dir", [app2,app3,zapp2], []),
-                    rebar_app_info:new(stdlib, "0.1", "/no-dir", [], []),
-                    rebar_app_info:new(kernel, "0.1", "/no-dir", [], []),
-                    rebar_app_info:new(zapp2, "0.1", "/no-dir", [], [])]],
+                   [rebar_app_info:new(app1, "0.1", "/no-dir", [app2, zapp1]),
+                    rebar_app_info:new(app2, "0.1", "/no-dir", [app3]),
+                    rebar_app_info:new(app3, "0.1", "/no-dir", [kernel]),
+                    rebar_app_info:new(zapp1, "0.1", "/no-dir", [app2,app3,zapp2]),
+                    rebar_app_info:new(stdlib, "0.1", "/no-dir", []),
+                    rebar_app_info:new(kernel, "0.1", "/no-dir", []),
+                    rebar_app_info:new(zapp2, "0.1", "/no-dir", [])]],
     {ok, Sorted} = sort_apps(Apps),
     ?assertMatch([stdlib, kernel, zapp2,
                   app3, app2, zapp1, app1],
-                 [rebar_app_info:name(App) || App <- Sorted]).
+                 [ec_cnv:to_atom(rebar_app_info:name(App)) || App <- Sorted]).
 
 -endif.
diff --git a/src/rebar_utils.erl b/src/rebar_utils.erl
index b83c03e..87387be 100644
--- a/src/rebar_utils.erl
+++ b/src/rebar_utils.erl
@@ -30,42 +30,27 @@
          filtermap/2,
          get_cwd/0,
          is_arch/1,
-         get_arch/0,
-         wordsize/0,
          sh/2,
          sh_send/3,
+         abort/0,
+         abort/2,
+         escript_foldl/3,
          find_files/2,
          find_files/3,
-         now_str/0,
          ensure_dir/1,
          beam_to_mod/1,
          beams/1,
-         erl_to_mod/1,
-         abort/0,
-         abort/2,
-         escript_foldl/3,
          find_executable/1,
-         prop_check/3,
          expand_code_path/0,
-         expand_env_variable/3,
          vcs_vsn/3,
          deprecated/3,
          deprecated/4,
-         get_deprecated_global/4,
-         get_deprecated_global/5,
-         get_experimental_global/3,
-         get_experimental_local/3,
-         get_deprecated_list/4,
-         get_deprecated_list/5,
-         get_deprecated_local/4,
-         get_deprecated_local/5,
          delayed_halt/1,
          erl_opts/1,
          src_dirs/1,
          ebin_dir/0,
          processing_base_dir/1,
          processing_base_dir/2,
-         patch_env/2,
          indent/1]).
 
 %% for internal use only
@@ -177,11 +162,6 @@ find_files(Dir, Regex, Recursive) ->
     filelib:fold_files(Dir, Regex, Recursive,
                        fun(F, Acc) -> [F | Acc] end, []).
 
-now_str() ->
-    {{Year, Month, Day}, {Hour, Minute, Second}} = calendar:local_time(),
-    lists:flatten(io_lib:format("~4b/~2..0b/~2..0b ~2..0b:~2..0b:~2..0b",
-                                [Year, Month, Day, Hour, Minute, Second])).
-
 %% TODO: filelib:ensure_dir/1 corrected in R13B04. Remove when we drop
 %% support for OTP releases older than R13B04.
 ensure_dir(Path) ->
@@ -194,27 +174,6 @@ ensure_dir(Path) ->
             Error
     end.
 
--spec abort() -> no_return().
-abort() ->
-    throw(rebar_abort).
-
--spec abort(string(), [term()]) -> no_return().
-abort(String, Args) ->
-    ?ERROR(String, Args),
-    abort().
-
-%% TODO: Rename emulate_escript_foldl to escript_foldl and remove
-%% this function when the time is right. escript:foldl/3 was an
-%% undocumented exported fun and has been removed in R14.
-escript_foldl(Fun, Acc, File) ->
-    {module, zip} = code:ensure_loaded(zip),
-    case erlang:function_exported(zip, foldl, 3) of
-        true ->
-            emulate_escript_foldl(Fun, Acc, File);
-        false ->
-            escript:foldl(Fun, Acc, File)
-    end.
-
 find_executable(Name) ->
     case os:find_executable(Name) of
         false -> false;
@@ -222,10 +181,6 @@ find_executable(Name) ->
             "\"" ++ filename:nativename(Path) ++ "\""
     end.
 
-%% Helper function for checking values and aborting when needed
-prop_check(true, _, _) -> true;
-prop_check(false, Msg, Args) -> ?ABORT(Msg, Args).
-
 %% Convert all the entries in the code path to absolute paths.
 expand_code_path() ->
     CodePath = lists:foldl(fun(Path, Acc) ->
@@ -233,25 +188,6 @@ expand_code_path() ->
                            end, [], code:get_path()),
     code:set_path(lists:reverse(CodePath)).
 
-%%
-%% Given env. variable FOO we want to expand all references to
-%% it in InStr. References can have two forms: $FOO and ${FOO}
-%% The end of form $FOO is delimited with whitespace or eol
-%%
-expand_env_variable(InStr, VarName, RawVarValue) ->
-    case string:chr(InStr, $$) of
-        0 ->
-            %% No variables to expand
-            InStr;
-        _ ->
-            ReOpts = [global, unicode, {return, list}],
-            VarValue = re:replace(RawVarValue, "\\\\", "\\\\\\\\", ReOpts),
-            %% Use a regex to match/replace:
-            %% Given variable "FOO": match $FOO\s | $FOOeol | ${FOO}
-            RegEx = io_lib:format("\\\$(~s(\\s|$)|{~s})", [VarName, VarName]),
-            re:replace(InStr, RegEx, [VarValue, "\\2"], ReOpts)
-    end.
-
 vcs_vsn(Config, Vsn, Dir) ->
     Key = {Vsn, Dir},
     Cache = rebar_state:get(Config, vsn_cache, dict:new()),
@@ -265,33 +201,6 @@ vcs_vsn(Config, Vsn, Dir) ->
             {Config, VsnString}
     end.
 
-get_deprecated_global(Config, OldOpt, NewOpt, When) ->
-    get_deprecated_global(Config, OldOpt, NewOpt, undefined, When).
-
-get_deprecated_global(Config, OldOpt, NewOpt, Default, When) ->
-    get_deprecated_3(fun rebar_state:get/3,
-                     Config, OldOpt, NewOpt, Default, When).
-
-get_experimental_global(Config, Opt, Default) ->
-    get_experimental_3(fun rebar_state:get/3, Config, Opt, Default).
-
-get_experimental_local(Config, Opt, Default) ->
-    get_experimental_3(fun rebar_state:get/3, Config, Opt, Default).
-
-get_deprecated_list(Config, OldOpt, NewOpt, When) ->
-    get_deprecated_list(Config, OldOpt, NewOpt, undefined, When).
-
-get_deprecated_list(Config, OldOpt, NewOpt, Default, When) ->
-    get_deprecated_3(fun rebar_state:get_list/3,
-                     Config, OldOpt, NewOpt, Default, When).
-
-get_deprecated_local(Config, OldOpt, NewOpt, When) ->
-    get_deprecated_local(Config, OldOpt, NewOpt, undefined, When).
-
-get_deprecated_local(Config, OldOpt, NewOpt, Default, When) ->
-    get_deprecated_3(fun rebar_state:get/3,
-                     Config, OldOpt, NewOpt, Default, When).
-
 deprecated(Old, New, Opts, When) when is_list(Opts) ->
     case lists:member(Old, Opts) of
         true ->
@@ -337,7 +246,7 @@ delayed_halt(Code) ->
     end.
 
 %% @doc Return list of erl_opts
--spec erl_opts(rebar_state:config()) -> list().
+-spec erl_opts(rebar_state:t()) -> list().
 erl_opts(Config) ->
     RawErlOpts = filter_defines(rebar_state:get(Config, erl_opts, []), []),
     Defines = [{d, list_to_atom(D)} ||
@@ -367,25 +276,6 @@ processing_base_dir(State, Dir) ->
     AbsDir = filename:absname(Dir),
     AbsDir =:= rebar_state:get(State, base_dir).
 
-%% @doc Returns the list of environment variables including 'REBAR' which
-%% points to the rebar executable used to execute the currently running
-%% command. The environment is not modified if rebar was invoked
-%% programmatically.
--spec patch_env(rebar_state:config(), [{string(), string()}])
-               -> [{string(), string()}].
-patch_env(Config, []) ->
-    %% If we reached an empty list, the env did not contain the REBAR variable.
-    case rebar_state:get(Config, escript, "") of
-        "" -> % rebar was invoked programmatically
-            [];
-        Path ->
-            [{"REBAR", Path}]
-    end;
-patch_env(_Config, [{"REBAR", _} | _]=All) ->
-    All;
-patch_env(Config, [E | Rest]) ->
-    [E | patch_env(Config, Rest)].
-
 %% ====================================================================
 %% Internal functions
 %% ====================================================================
@@ -426,30 +316,6 @@ otp_release1(Rel) ->
             binary:bin_to_list(Vsn, {0, Size - 1})
     end.
 
-get_deprecated_3(Get, Config, OldOpt, NewOpt, Default, When) ->
-    case Get(Config, NewOpt, Default) of
-        Default ->
-            case Get(Config, OldOpt, Default) of
-                Default ->
-                    Default;
-                Old ->
-                    deprecated(OldOpt, NewOpt, When),
-                    Old
-            end;
-        New ->
-            New
-    end.
-
-get_experimental_3(Get, Config, Opt, Default) ->
-    Val = Get(Config, Opt, Default),
-    case Val of
-        Default ->
-            Default;
-        Val ->
-            ?CONSOLE("NOTICE: Using experimental option '~p'~n", [Opt]),
-            Val
-    end.
-
 %% We do the shell variable substitution ourselves on Windows and hope that the
 %% command doesn't use any other shell magic.
 patch_on_windows(Cmd, Env) ->
@@ -466,6 +332,25 @@ patch_on_windows(Cmd, Env) ->
             Cmd
     end.
 
+%%
+%% Given env. variable FOO we want to expand all references to
+%% it in InStr. References can have two forms: $FOO and ${FOO}
+%% The end of form $FOO is delimited with whitespace or eol
+%%
+expand_env_variable(InStr, VarName, RawVarValue) ->
+    case string:chr(InStr, $$) of
+        0 ->
+            %% No variables to expand
+            InStr;
+        _ ->
+            ReOpts = [global, unicode, {return, list}],
+            VarValue = re:replace(RawVarValue, "\\\\", "\\\\\\\\", ReOpts),
+            %% Use a regex to match/replace:
+            %% Given variable "FOO": match $FOO\s | $FOOeol | ${FOO}
+            RegEx = io_lib:format("\\\$(~s(\\s|$)|{~s})", [VarName, VarName]),
+            re:replace(InStr, RegEx, [VarValue, "\\2"], ReOpts)
+    end.
+
 expand_sh_flag(return_on_error) ->
     {error_handler,
      fun(_Command, Err) ->
@@ -521,14 +406,19 @@ sh_loop(Port, Fun, Acc) ->
 beam_to_mod(Filename) ->
     list_to_atom(filename:basename(Filename, ".beam")).
 
-erl_to_mod(Filename) ->
-    list_to_atom(filename:rootname(filename:basename(Filename))).
-
 beams(Dir) ->
     filelib:fold_files(Dir, ".*\.beam\$", true,
                        fun(F, Acc) -> [F | Acc] end, []).
 
-emulate_escript_foldl(Fun, Acc, File) ->
+-spec abort() -> no_return().
+abort() ->
+    throw(rebar_abort).
+-spec abort(string(), [term()]) -> no_return().
+abort(String, Args) ->
+    ?ERROR(String, Args),
+    abort().
+
+escript_foldl(Fun, Acc, File) ->
     case escript:extract(File, [compile_source]) of
         {ok, [_Shebang, _Comment, _EmuArgs, Body]} ->
             case Body of
diff --git a/test/rebar_compile_SUITE.erl b/test/rebar_compile_SUITE.erl
index f9f79af..7b17409 100644
--- a/test/rebar_compile_SUITE.erl
+++ b/test/rebar_compile_SUITE.erl
@@ -25,7 +25,7 @@ init_per_testcase(_, Config) ->
     DataDir = proplists:get_value(data_dir, Config),
     AppsDir = filename:join([DataDir, create_random_name("apps_dir1_")]),
     ok = ec_file:mkdir_p(AppsDir),
-    Verbosity = rebar3:log_level([]),
+    Verbosity = rebar3:log_level(),
     rebar_log:init(command_line, Verbosity),
     State = rebar_state:new(),
     [{apps, AppsDir}, {state, State} | Config].