Reload .app files for path deps in tracer, closes #10718

Author: josevalim

lib/mix/lib/mix/compilers/application_tracer.ex

@@ -7,11 +7,22 @@ defmodule Mix.Compilers.ApplicationTracer do
   def init({stale_deps, opts}) do
     config = Mix.Project.config()
     manifest = manifest(config)
+    modified = Mix.Utils.last_modified(manifest)
 
-    if Mix.Utils.stale?([Mix.Project.config_mtime()], [manifest]) do
-      build_manifest(config, manifest)
-    else
-      read_manifest(manifest, stale_deps) || build_manifest(config, manifest)
+    cond do
+      Mix.Utils.stale?([Mix.Project.config_mtime()], [modified]) ->
+        build_manifest(config, manifest)
+
+      table = read_manifest(manifest, stale_deps) ->
+        for %{app: app, scm: scm, opts: opts} <- Mix.Dep.cached(),
+            not scm.fetchable?,
+            Mix.Utils.last_modified(Path.join([opts[:build], "ebin", "#{app}.app"])) > modified do
+          delete_app(table, app)
+          store_app(table, app)
+        end
+
+      true ->
+        build_manifest(config, manifest)
     end
 
     setup_warnings_table(config)
@@ -204,9 +215,7 @@ defmodule Mix.Compilers.ApplicationTracer do
       Map.has_key?(seen, app) ->
         seen
 
-      modules = Application.spec(app, :modules) ->
-        :ets.insert(table, Enum.map(modules, &{&1}))
-
+      store_app(table, app) ->
         seen
         |> Map.put(app, true)
         |> store_apps(table, Application.spec(app, :applications))
@@ -216,4 +225,17 @@ defmodule Mix.Compilers.ApplicationTracer do
         seen
     end
   end
+
+  defp delete_app(table, app) do
+    :ets.match_delete(table, {:"$_", app})
+  end
+
+  defp store_app(table, app) do
+    if modules = Application.spec(app, :modules) do
+      :ets.insert(table, Enum.map(modules, &{&1, app}))
+      true
+    else
+      false
+    end
+  end
 end

lib/mix/test/mix/umbrella_test.exs

@@ -474,6 +474,35 @@ defmodule Mix.UmbrellaTest do
     end)
   end
 
+  test "reloads app in app tracer if .app changes" do
+    in_fixture("umbrella_dep/deps/umbrella/apps", fn ->
+      deps = [{:foo, in_umbrella: true}]
+      Mix.Project.in_project(:bar, "bar", [deps: deps], fn _ ->
+        Mix.Task.run("compile", ["--verbose"])
+        mtime = File.stat!("../foo/lib/foo.ex").mtime
+
+        File.write!("../foo/lib/foo.ex", """
+        defmodule Foo.VeryNew do
+          def hello, do: :ok
+        end
+        """)
+
+        File.write!("lib/bar.ex", """
+        defmodule Bar.VeryNew do
+          def hello, do: Foo.VeryNew.hello()
+        end
+        """)
+
+        Mix.Task.clear()
+        Application.unload(:foo)
+        ensure_touched("../foo/lib/foo.ex", mtime)
+
+        assert Mix.Task.run("compile", ["--verbose"]) == {:ok, []}
+        assert_receive {:mix_shell, :info, ["Compiled lib/bar.ex"]}
+      end)
+    end)
+  end
+
   test "reconsolidates after path dependency changes" do
     in_fixture("umbrella_dep/deps/umbrella/apps", fn ->
       Mix.Project.in_project(:bar, "bar", fn _ ->