Prune tasks when build per environment is on

Author: José Valim

lib/mix/lib/mix/project.ex

@@ -71,7 +71,7 @@ defmodule Mix.Project do
   @doc false
   def deps_config(config // config()) do
     [ build_path: build_path(config),
-      builds_per_environment: config[:builds_per_environment],
+      build_per_environment: config[:build_per_environment],
       deps_path: deps_path(config) ]
   end
 
@@ -187,7 +187,7 @@ defmodule Mix.Project do
       Mix.Project.build_path
       #=> "/path/to/project/_build/shared"
 
-  If :builds_per_environment is set to true, it
+  If :build_per_environment is set to true, it
   will create a new build per environment:
 
       Mix.env
@@ -197,7 +197,7 @@ defmodule Mix.Project do
 
   """
   def build_path(config // config()) do
-    config[:build_path] || if config[:builds_per_environment] do
+    config[:build_path] || if config[:build_per_environment] do
       Path.expand("_build/#{Mix.env}")
     else
       Path.expand("_build/shared")
@@ -322,7 +322,7 @@ defmodule Mix.Project do
   end
 
   defp default_config do
-    [ builds_per_environment: false,
+    [ build_per_environment: false,
       default_task: "run",
       deps: [],
       deps_path: "deps",

lib/mix/lib/mix/tasks/deps.check.ex

@@ -1,7 +1,7 @@
 defmodule Mix.Tasks.Deps.Check do
   use Mix.Task
 
-  import Mix.Deps, only: [loaded: 0, format_dep: 1, format_status: 1, check_lock: 2]
+  import Mix.Deps, only: [loaded: 0, format_dep: 1, format_status: 1, check_lock: 2, ok?: 1]
 
   @hidden true
   @shortdoc "Check if all dependencies are valid"
@@ -17,6 +17,8 @@ defmodule Mix.Tasks.Deps.Check do
     lock = Mix.Deps.Lock.read
     all  = Enum.map loaded, &check_lock(&1, lock)
 
+    prune_deps(all)
+
     case Enum.partition all, &ok?/1 do
       { _, [] }     -> :ok
       { _, not_ok } ->
@@ -32,6 +34,23 @@ defmodule Mix.Tasks.Deps.Check do
     end
   end
 
-  defp ok?(Mix.Dep[status: { :ok, _ }]), do: true
-  defp ok?(_),                           do: false
+  # If the build is per environment, we should be able to look
+  # at all dependencies and remove the builds that no longer
+  # has a dependnecy defined for them.
+  defp prune_deps(all) do
+    config = Mix.project
+    if config[:build_per_environment] do
+      paths = Mix.Project.build_path(config)
+              |> Path.join("lib/*")
+              |> Path.wildcard
+              |> List.delete(Mix.Project.app_path(config))
+
+      to_prune = Enum.reduce(all, paths, &(&2 -- Mix.Deps.source_paths(&1)))
+
+      Enum.map(to_prune, fn path ->
+        Code.delete_path(path)
+        File.rm_rf!(path)
+      end)
+    end
+  end
 end

lib/mix/test/fixtures/deps_status/deps/ok/mix.exs

@@ -3,6 +3,6 @@ defmodule Ok.Mixfile do
 
   def project do
     [ app: :ok,
-      version: "1.0" ]
+      version: "0.1.0" ]
   end
 end

lib/mix/test/mix/tasks/compile.elixir_test.exs

@@ -29,7 +29,7 @@ defmodule Mix.Tasks.Compile.ElixirTest do
 
   test "compiles a project with per environment build" do
     Mix.Project.pop
-    Mix.ProjectStack.post_config [builds_per_environment: true]
+    Mix.ProjectStack.post_config [build_per_environment: true]
     Mix.Project.push MixTest.Case.Sample
 
     in_fixture "no_mixfile", fn ->

lib/mix/test/mix/tasks/deps_test.exs

@@ -5,7 +5,7 @@ defmodule Mix.Tasks.DepsTest do
 
   defmodule DepsApp do
     def project do
-      [ app: :deos, version: "0.1.0",
+      [ app: :deps, version: "0.1.0",
         deps: [
           { :ok, "0.1.0",         github: "elixir-lang/ok" },
           { :invalidvsn, "0.2.0", path: "deps/invalidvsn" },
@@ -19,7 +19,7 @@ defmodule Mix.Tasks.DepsTest do
 
   defmodule SuccessfulDepsApp do
     def project do
-      [ app: :success, version: "0.1.0",
+      [ app: :sample, version: "0.1.0",
         deps: [
           { :ok, "0.1.0", path: "deps/ok" }
         ]
@@ -154,6 +154,29 @@ defmodule Mix.Tasks.DepsTest do
     Mix.Project.pop
   end
 
+  test "compiles and prunes builds per environment" do
+    Mix.ProjectStack.post_config [build_per_environment: true]
+    Mix.Project.push SuccessfulDepsApp
+
+    in_fixture "deps_status", fn ->
+      Mix.Tasks.Deps.Compile.run []
+      assert File.exists?("_build/dev/lib/ok/ebin/ok.app")
+
+      Mix.Tasks.Compile.run []
+      assert File.exists?("_build/dev/lib/sample/ebin/sample.app")
+
+      Mix.ProjectStack.post_config [build_per_environment: true, deps: []]
+      Mix.Project.pop
+      Mix.Project.push SuccessfulDepsApp
+
+      Mix.Tasks.Deps.Check.run []
+      refute File.exists?("_build/dev/lib/ok/ebin/ok.app")
+      assert File.exists?("_build/dev/lib/sample/ebin/sample.app")
+    end
+  after
+    Mix.Project.pop
+  end
+
   test "unlocks all deps" do
     Mix.Project.push DepsApp
     in_fixture "no_mixfile", fn ->