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-module(rebar_paths).
-include("rebar.hrl").
-type target() :: deps | plugins.
-type targets() :: [target(), ...].
-export_type([target/0, targets/0]).
-export([set_paths/2, unset_paths/2]).
-export([clashing_apps/2]).
-ifdef(TEST).
-export([misloaded_modules/3]).
-endif.
-spec set_paths(targets(), rebar_state:t()) -> ok.
set_paths(UserTargets, State) ->
Targets = normalize_targets(UserTargets),
GroupPaths = path_groups(Targets, State),
Paths = lists:append([P || {_, P} <- GroupPaths]),
[code:del_path(P) || P <- Paths],
code:add_pathsa(lists:reverse(Paths)),
% set path breaks with escripts; we gotta do it by hand
% true = code:set_path(lists:append([P || {_, P} <- GroupPaths])),
AppGroups = app_groups(Targets, State),
purge_and_load(AppGroups, code:all_loaded(), sets:new()),
ok.
-spec unset_paths(targets(), rebar_state:t()) -> ok.
unset_paths(UserTargets, State) ->
Targets = normalize_targets(UserTargets),
GroupPaths = path_groups(Targets, State),
Paths = lists:append([P || {_, P} <- GroupPaths]),
[code:del_path(P) || P <- Paths],
purge(Paths, code:all_loaded()),
ok.
clashing_apps(Targets, State) ->
AppGroups = app_groups(Targets, State),
AppNames = [{G, sets:from_list(
[rebar_app_info:name(App) || App <- Apps]
)} || {G, Apps} <- AppGroups],
clashing_app_names(sets:new(), AppNames, []).
%%%%%%%%%%%%%%%
%%% PRIVATE %%%
%%%%%%%%%%%%%%%
%% The paths are to be set in the reverse order; i.e. the default
%% path is always last when possible (minimize cases where a build
%% tool version clashes with an app's), and put the highest priorities
%% first.
-spec normalize_targets(targets()) -> targets().
normalize_targets(List) ->
%% Plan for the eventuality of getting values piped in
%% from future versions of rebar3, possibly from plugins and so on,
%% which means we'd risk failing kind of violently. We only support
%% deps and plugins
TmpList = lists:foldl(
fun(deps, [deps | _] = Acc) -> Acc;
(plugins, [plugins | _] = Acc) -> Acc;
(deps, Acc) -> [deps | Acc -- [deps]];
(plugins, Acc) -> [plugins | Acc -- [plugins]];
(_, Acc) -> Acc
end,
[],
List
),
lists:reverse(TmpList).
purge_and_load([], _, _) ->
ok;
purge_and_load([{_Group, Apps}|Rest], ModPaths, Seen) ->
%% We have: a list of all applications in the current priority group,
%% a list of all loaded modules with their active path, and a list of
%% seen applications.
%%
%% We do the following:
%% 1. identify the apps that have not been solved yet
%% 2. find the paths for all apps in the current group
%% 3. unload and reload apps that may have changed paths in order
%% to get updated module lists and specs
%% (we ignore started apps and apps that have not run for this)
%% 4. create a list of modules to check from that app list
%% 5. check the modules to match their currently loaded paths with
%% the path set from the apps in the current group; modules
%% that differ must be purged; others can stay
%% 1)
AppNames = [AppName || App <- Apps,
AppName <- [rebar_app_info:name(App)],
not sets:is_element(AppName, Seen)],
GoodApps = [App || AppName <- AppNames,
App <- Apps,
rebar_app_info:name(App) =:= AppName],
%% 2)
%% (no need for extra_src_dirs since those get put into ebin;
%% also no need for OTP libs; we want to allow overtaking them)
GoodAppPaths = [rebar_app_info:ebin_dir(App) || App <- GoodApps],
%% 3)
[begin
AtomApp = binary_to_atom(AppName, utf8),
%% blind load/unload won't interrupt an already-running app,
%% preventing odd errors, maybe!
case application:unload(AtomApp) of
ok -> application:load(AtomApp);
_ -> ok
end
end || AppName <- AppNames,
%% Shouldn't unload ourselves; rebar runs without ever
%% being started and unloading breaks logging!
AppName =/= <<"rebar">>],
%% 4)
CandidateMods = lists:append(
%% Start by asking the currently loaded app (if loaded)
%% since it would be the primary source of conflicting modules
[case application:get_key(AppName, modules) of
{ok, Mods} ->
Mods;
undefined ->
%% if not found, parse the app file on disk, in case
%% the app's modules are used without it being loaded
case rebar_app_info:app_details(App) of
[] -> [];
Details -> proplists:get_value(modules, Details, [])
end
end || App <- GoodApps,
AppName <- [binary_to_atom(rebar_app_info:name(App), utf8)]]
),
%% 5)
Mods = misloaded_modules(CandidateMods, GoodAppPaths, ModPaths),
[purge_mod(Mod) || Mod <- Mods],
purge_and_load(Rest, ModPaths,
sets:union(Seen, sets:from_list(AppNames))).
purge(Paths, ModPaths) ->
SortedPaths = lists:sort(Paths),
lists:map(fun purge_mod/1, lists:usort(
[Mod || {Mod, Path} <- ModPaths,
is_list(Path), % not 'preloaded' or mocked
any_prefix(Path, SortedPaths)]
)).
misloaded_modules(Mods, GoodAppPaths, ModPaths) ->
%% Identify paths that are invalid; i.e. app paths that cover an
%% app in the desired group, but are not in the desired group.
lists:usort(
[Mod || Mod <- Mods,
{_, Path} <- [lists:keyfind(Mod, 1, ModPaths)],
is_list(Path), % not 'preloaded' or mocked
not any_prefix(Path, GoodAppPaths)]
).
any_prefix(Path, Paths) ->
lists:any(fun(P) -> lists:prefix(P, Path) end, Paths).
%% assume paths currently set are good; only unload a module so next call
%% uses the correctly set paths
purge_mod(Mod) ->
case erlang:check_process_code(self(), Mod) of
false ->
code:purge(Mod),
code:delete(Mod);
_ ->
%% cannot purge safely without killing ourselves
code:soft_purge(Mod) andalso
code:delete(Mod)
end.
%% This is a tricky O(n²) check since we want to
%% know whether an app clashes with any of the top priority groups.
%%
%% For example, let's say we have `[deps, plugins]', then we want
%% to find the plugins that clash with deps:
%%
%% `[{deps, [ClashingPlugins]}, {plugins, []}]'
%%
%% In case we'd ever have alternative or additional types, we can
%% find all clashes from other 'groups'.
clashing_app_names(_, [], Acc) ->
lists:reverse(Acc);
clashing_app_names(PrevNames, [{G,AppNames} | Rest], Acc) ->
CurrentNames = sets:subtract(AppNames, PrevNames),
NextNames = sets:subtract(sets:union([A || {_, A} <- Rest]), PrevNames),
Clashes = sets:intersection(CurrentNames, NextNames),
NewAcc = [{G, sets:to_list(Clashes)} | Acc],
clashing_app_names(sets:union(PrevNames, CurrentNames), Rest, NewAcc).
path_groups(Targets, State) ->
[{Target, get_paths(Target, State)} || Target <- Targets].
app_groups(Targets, State) ->
[{Target, get_apps(Target, State)} || Target <- Targets].
get_paths(deps, State) ->
rebar_state:code_paths(State, all_deps);
get_paths(plugins, State) ->
rebar_state:code_paths(State, all_plugin_deps).
get_apps(deps, State) ->
%% The code paths for deps also include the top level apps
%% and the extras, which we don't have here; we have to
%% add the apps by hand
case rebar_state:project_apps(State) of
undefined -> [];
List -> List
end ++
rebar_state:all_deps(State);
get_apps(plugins, State) ->
rebar_state:all_plugin_deps(State).
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