Handle aliases with code recursion

It addresses a regression introduced in 97e8b02.

Closes nerves-project/nerves#557.

Author: josevalim

lib/mix/lib/mix/task.ex

@@ -355,12 +355,12 @@ defmodule Mix.Task do
     alias = Mix.Project.config()[:aliases][String.to_atom(task)]
 
     cond do
-      is_nil(alias) ->
-        run_task(proj, task, args)
-
-      Mix.TasksServer.run({:alias, task, proj}) ->
+      alias && Mix.TasksServer.run({:alias, task, proj}) ->
         run_alias(List.wrap(alias), args, proj, task, :ok)
 
+      !Mix.TasksServer.get({:task, task, proj}) ->
+        run_task(proj, task, args)
+
       true ->
         :noop
     end
@@ -371,8 +371,8 @@ defmodule Mix.Task do
     # 2. Otherwise we compile and load dependencies
     # 3. Finally, we compile the current project in hope it is available.
     module =
-      get_task_or_run(proj, task, fn -> Mix.Task.run("deps.loadpaths") end) ||
-        get_task_or_run(proj, task, fn -> Mix.Task.run("compile", []) end) ||
+      get_task_or_run(proj, task, fn -> run("deps.loadpaths") end) ||
+        get_task_or_run(proj, task, fn -> run("compile", []) end) ||
         get!(task)
 
     recursive = recursive(module)
@@ -450,7 +450,8 @@ defmodule Mix.Task do
     run_alias(t, alias_args, proj, original_task, res)
   end
 
-  defp run_alias([], _alias_task, _proj, _original_task, res) do
+  defp run_alias([], _alias_args, proj, original_task, res) do
+    Mix.TasksServer.put({:task, original_task, proj})
     res
   end
 

lib/mix/lib/mix/tasks_server.ex

@@ -21,6 +21,10 @@ defmodule Mix.TasksServer do
     Agent.update(@name, &Map.put(&1, tuple, true), @timeout)
   end
 
+  def get(tuple) do
+    Agent.get(@name, &Map.get(&1, tuple), @timeout)
+  end
+
   def delete_many(many) do
     Agent.update(@name, &Map.drop(&1, many), @timeout)
   end

lib/mix/test/mix/aliases_test.exs

@@ -10,11 +10,14 @@ defmodule Mix.AliasesTest do
           h: "hello",
           p: &inspect/1,
           compile: "hello",
+          cmd: &call_cmd/1,
           help: ["help", "hello"],
           "nested.h": [&Mix.shell().info(inspect(&1)), "h foo bar"]
         ]
       ]
     end
+
+    defp call_cmd(args), do: Mix.Task.run("cmd", args)
   end
 
   setup do
@@ -50,13 +53,18 @@ defmodule Mix.AliasesTest do
     assert Mix.Task.run("compile", []) == :noop
   end
 
-  test "run alias override with recursion" do
+  test "run alias override with name-recursion" do
     assert Mix.Task.rerun("help", []) == "Hello, World!"
     assert_received {:mix_shell, :info, ["mix test" <> _]}
 
     # Arguments are passed to the recursive task and not the last one.
     assert ExUnit.CaptureIO.capture_io(fn ->
-             Mix.Task.rerun("help", ["test"]) == "Hello, World!"
+             Mix.Task.rerun("help", ["test"])
            end) =~ "mix test"
   end
+
+  test "run alias override with code-recursion" do
+    assert Mix.Task.rerun("cmd", ["echo", "hello"]) == :ok
+    assert_received {:mix_shell, :run, ["hello" <> _]}
+  end
 end