Fix bug where umbrella tasks were not reenabled

Closes #2058.

Author: ericmj

CHANGELOG.md

@@ -11,6 +11,7 @@
   * [Mix] Use absolute symbolic links on Windows for `_build` instead of copying
   * [Mix] Add `Mix.compilers` that returns all default compilers used by mix tasks
   * [Mix] Add `mix archive`
+  * [Mix] Issue warning and reset mtime for source files from the future
   * [String] Improve performance of `String.split/1`
   * [Typespec] Allow `%Struct{}` syntax to be used in typespecs
 
@@ -28,6 +29,7 @@
   * [Mix] Ensure Mix dependencies are not compiled every second time when `mix deps.compile` is invoked
   * [Mix] Fix a bug where `Mix.shell.error/1` and friends choked when printing a map
   * [Mix] Ensure multiple `@external_resource` entries are read by Mix compilers
+  * [Mix] Fix a bug where tasks for umbrella projects were not properly reenabled
   * [Stream] Fix bug when `flat_map` is used inside another `flat_map` with an Enumerable
   * [Typespec] Fix a bug where the `list` typespec was incorrectly rendered as `[]`
 

lib/mix/lib/mix/task.ex

@@ -204,6 +204,8 @@ defmodule Mix.Task do
     task   = to_string(task)
     module = get!(task)
 
+    Mix.TasksServer.delete_task(task, Mix.Project.get)
+
     recur module, fn project ->
       Mix.TasksServer.delete_task(task, project)
     end

lib/mix/test/mix/task_test.exs

@@ -58,6 +58,19 @@ defmodule Mix.TaskTest do
     assert Mix.Task.run("hello") == "Hello, World!"
   end
 
+  test "reenable for umbrella" do
+    in_fixture "umbrella_dep/deps/umbrella", fn ->
+      Mix.Project.in_project(:umbrella, ".", fn _ ->
+        assert [:ok, :ok] = Mix.Task.run "clean"
+        assert :noop      = Mix.Task.run "clean"
+
+        Mix.Task.reenable "clean"
+        assert [:ok, :ok] = Mix.Task.run "clean"
+        assert :noop      = Mix.Task.run "clean"
+      end)
+    end
+  end
+
   test :get! do
     assert Mix.Task.get!("hello") == Mix.Tasks.Hello