Abstracted path management

Move path management out of rebar_utils manual code path function
handling (which we leave there for backwards compat), and centralize
them to allow easier coordination of paths between plugins and deps.

On top of path handling, do a check of loaded modules to only purge and
reload those that actually need it done in order to prevent all kinds of
weird interaction and accidental purge kills. It also allows the
possible cohabitation of both at once, with a "in case of conflict pick
X" as a policy

Changing path handling in providers also highlighted a bunch of bugs in
some tests and appears to fix some in other providers, specifically
around plugins.

3 files changed, 215 insertions, 3 deletions

diff --git a/test/rebar_compile_SUITE.erl b/test/rebar_compile_SUITE.erl
index 867460c..6b1d791 100644
--- a/test/rebar_compile_SUITE.erl
+++ b/test/rebar_compile_SUITE.erl
@@ -1856,7 +1856,7 @@ include_file_in_src_test_multiapp(Config) ->
     AppDir1 = filename:join([?config(apps, Config), "lib", Name1]),
     AppDir2 = filename:join([?config(apps, Config), "lib", Name2]),
     Vsn = rebar_test_utils:create_random_vsn(),
-    rebar_test_utils:create_app(AppDir1, Name1, Vsn, [kernel, stdlib]),
+    rebar_test_utils:create_app(AppDir1, Name1, Vsn, [kernel, stdlib, list_to_atom(Name2)]),
     rebar_test_utils:create_app(AppDir2, Name2, Vsn, [kernel, stdlib]),
 
     Src = "-module(test).\n"
@@ -1878,7 +1878,8 @@ include_file_in_src_test_multiapp(Config) ->
     RebarConfig = [],
     rebar_test_utils:run_and_check(Config, RebarConfig,
                                    ["as", "test", "compile"],
-                                   {ok, [{app, Name1}]}).
+                                   {ok, [{app, Name1}]}),
+    ok.
 
 %% this test sets the env var, compiles, records the file last modified timestamp,
 %% recompiles and compares the file last modified timestamp to ensure it hasn't
diff --git a/test/rebar_paths_SUITE.erl b/test/rebar_paths_SUITE.erl
new file mode 100644
index 0000000..48a7000
--- /dev/null
+++ b/test/rebar_paths_SUITE.erl
@@ -0,0 +1,211 @@
+-module(rebar_paths_SUITE).
+-include_lib("eunit/include/eunit.hrl").
+-include_lib("common_test/include/ct.hrl").
+-compile(export_all).
+
+all() ->
+    [%clashing_apps,
+     check_modules,
+     set_paths
+    ].
+
+init_per_testcase(Case, Config) ->
+    BasePaths = code:get_path(),
+    %% This test checks that the right module sets get loaded; however, we must
+    %% ensure that we do not have clashes with other test suites' loaded modules,
+    %% which we cannot track. As such, we have to ensure all module names here are
+    %% unique.
+    %%
+    %% This is done by hand; if you see this test suite failing on its own, you
+    %% probably wrote a test suite that clashes!
+    Dir = filename:join([?config(priv_dir, Config), atom_to_list(?MODULE),
+                         atom_to_list(Case)]),
+    InDir = fun(Path) -> filename:join([Dir, Path]) end,
+    ADep = fake_app(<<"rp_a">>, <<"1.0.0">>, InDir("_build/default/lib/rp_a/")),
+    BDep = fake_app(<<"rp_b">>, <<"1.0.0">>, InDir("_build/default/lib/rp_b/")),
+    CDep = fake_app(<<"rp_c">>, <<"1.0.0">>, InDir("_build/default/lib/rp_c/")),
+    DDep = fake_app(<<"rp_d">>, <<"1.0.0">>, InDir("_build/default/lib/rp_d/")),
+    RelxDep = fake_app(<<"relx">>, <<"1.0.0">>, InDir("_build/default/lib/relx/")),
+
+    APlug = fake_app(<<"rp_a">>, <<"1.0.0">>,
+                     InDir("_build/default/plugins/lib/rp_a/")),
+    RelxPlug = fake_app(<<"relx">>, <<"1.1.1">>,
+                        InDir("_build/default/plugins/lib/relx")),
+    EPlug = fake_app(<<"rp_e">>, <<"1.0.0">>,
+                     InDir("_build/default/plugins/lib/rp_e/")),
+
+    S0 = rebar_state:new(),
+    S1 = rebar_state:all_deps(S0, [ADep, BDep, CDep, DDep, RelxDep]),
+    S2 = rebar_state:all_plugin_deps(S1, [APlug, RelxPlug]),
+    S3 = rebar_state:code_paths(S2, default, code:get_path()),
+    S4 = rebar_state:code_paths(
+        S3,
+        all_deps,
+        [rebar_app_info:ebin_dir(A) || A <- [ADep, BDep, CDep, DDep, RelxDep]]
+    ),
+    S5 = rebar_state:code_paths(
+        S4,
+        all_plugin_deps,
+        [rebar_app_info:ebin_dir(A) || A <- [APlug, RelxPlug, EPlug]]
+    ),
+    [{base_paths, BasePaths}, {root_dir, Dir}, {state, S5} | Config].
+
+end_per_testcase(_, Config) ->
+    %% this is deeply annoying because we interfere with rebar3's own
+    %% path handling!
+    rebar_paths:unset_paths([plugins, deps], ?config(state, Config)),
+    Config.
+
+fake_app(Name, Vsn, OutDir) ->
+    {ok, App} = rebar_app_info:new(Name, Vsn, OutDir),
+    compile_fake_appmod(App),
+    App.
+
+compile_fake_appmod(App) ->
+    OutDir = rebar_app_info:ebin_dir(App),
+    Vsn = rebar_app_info:original_vsn(App),
+    Name = rebar_app_info:name(App),
+
+    ok = filelib:ensure_dir(filename:join([OutDir, ".touch"])),
+
+    AppFile = [
+      "{application,", Name, ", "
+      " [{description,  \"some app\"}, "
+      "  {vsn, \"", Vsn, "\"}, "
+      "  {modules, [",Name,"]}, "
+      "  {registered, []}, "
+      "  {applications, [stdlib, kernel]} "
+      " ]}. "],
+
+    ok = file:write_file(filename:join([OutDir, <<Name/binary, ".app">>]), AppFile),
+
+    Mod = [{attribute, 1, module, binary_to_atom(Name, utf8)},
+           {attribute, 2, export, [{f,0}]},
+           {function,3,f,0,
+            [{clause,3, [], [],
+              [{string,3,OutDir}]
+            }]}
+          ],
+
+    {ok, _, Bin} = compile:forms(Mod),
+    ok = file:write_file(filename:join([OutDir, <<Name/binary, ".beam">>]), Bin).
+
+clashing_apps(Config) ->
+    Clashes = rebar_paths:clashing_apps([deps, plugins],
+                                        ?config(state, Config)),
+    ct:pal("Clashes: ~p", [Clashes]),
+
+    ?assertEqual([<<"relx">>, <<"rp_a">>], lists:sort(proplists:get_value(deps, Clashes))),
+    ?assertEqual(undefined, proplists:get_value(plugins, Clashes)),
+    ok.
+
+set_paths(Config) ->
+    State = ?config(state, Config),
+    RootDir = filename:split(?config(root_dir, Config)),
+    rebar_paths:set_paths([plugins, deps], State),
+    PluginPaths = code:get_path(),
+    rebar_paths:set_paths([deps, plugins], State),
+    DepPaths = code:get_path(),
+
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "plugins", "lib", "rp_a", "ebin"],
+       find_first_instance("rp_a", PluginPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_b", "ebin"],
+       find_first_instance("rp_b", PluginPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_c", "ebin"],
+       find_first_instance("rp_c", PluginPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_d", "ebin"],
+       find_first_instance("rp_d", PluginPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "plugins", "lib",  "rp_e", "ebin"],
+       find_first_instance("rp_e", PluginPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "plugins", "lib", "relx", "ebin"],
+       find_first_instance("relx", PluginPaths)
+    ),
+
+
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_a", "ebin"],
+       find_first_instance("rp_a", DepPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_b", "ebin"],
+       find_first_instance("rp_b", DepPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_c", "ebin"],
+       find_first_instance("rp_c", DepPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "rp_d", "ebin"],
+       find_first_instance("rp_d", DepPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "plugins", "lib", "rp_e", "ebin"],
+       find_first_instance("rp_e", DepPaths)
+    ),
+    ?assertEqual(
+       RootDir ++ ["_build", "default", "lib", "relx", "ebin"],
+       find_first_instance("relx", DepPaths)
+    ),
+    ok.
+
+check_modules(Config) ->
+    State = ?config(state, Config),
+    RootDir = ?config(root_dir, Config)++"/",
+    rebar_paths:set_paths([plugins, deps], State),
+    ct:pal("code:get_path() -> ~p", [code:get_path()]),
+
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/rp_a/ebin", rp_a:f()),
+    ct:pal("~p", [catch file:list_dir(RootDir ++ "_build/default/lib/")]),
+    ct:pal("~p", [catch file:list_dir(RootDir ++ "_build/default/lib/rp_b/")]),
+    ct:pal("~p", [catch file:list_dir(RootDir ++ "_build/default/lib/rp_b/ebin")]),
+    ct:pal("~p", [catch b:module_info()]),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_b/ebin", rp_b:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_c/ebin", rp_c:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_d/ebin", rp_d:f()),
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/rp_e/ebin", rp_e:f()),
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/relx/ebin", relx:f()),
+    ?assertEqual(3, length(relx:module_info(exports))), % can't replace bundled
+
+    rebar_paths:set_paths([deps, plugins], State),
+    ct:pal("code:get_path() -> ~p", [code:get_path()]),
+
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_a/ebin", rp_a:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_b/ebin", rp_b:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_c/ebin", rp_c:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_d/ebin", rp_d:f()),
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/rp_e/ebin", rp_e:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/relx/ebin", relx:f()),
+    ?assertEqual(3, length(relx:module_info(exports))), % can't replace bundled
+
+    %% once again
+    rebar_paths:set_paths([plugins, deps], State),
+    ct:pal("code:get_path() -> ~p", [code:get_path()]),
+
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/rp_a/ebin", rp_a:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_b/ebin", rp_b:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_c/ebin", rp_c:f()),
+    ?assertEqual(RootDir ++ "_build/default/lib/rp_d/ebin", rp_d:f()),
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/rp_e/ebin", rp_e:f()),
+    ?assertEqual(RootDir ++ "_build/default/plugins/lib/relx/ebin", relx:f()),
+    ?assertEqual(3, length(relx:module_info(exports))), % can't replace bundled
+    ok.
+
+find_first_instance(Frag, []) ->
+    {not_found, Frag};
+find_first_instance(Frag, [Path|Rest]) ->
+    Frags = filename:split(Path),
+    case lists:member(Frag, Frags) of
+        true -> Frags;
+        false -> find_first_instance(Frag, Rest)
+    end.
diff --git a/test/rebar_plugins_SUITE.erl b/test/rebar_plugins_SUITE.erl
index 2d74539..c7a5d51 100644
--- a/test/rebar_plugins_SUITE.erl
+++ b/test/rebar_plugins_SUITE.erl
@@ -335,7 +335,7 @@ project_plugins(Config) ->
     rebar_test_utils:create_app(AppDir, Name, Vsn, [kernel, stdlib]),
 
     DepName = rebar_test_utils:create_random_name("dep1_"),
-    PluginName = "compile",
+    PluginName = "compile_plugin",
     PluginName2 = "release",
 
     Plugins = rebar_test_utils:expand_deps(git, [{PluginName, Vsn, []}, {PluginName2, Vsn, []}]),