Ensure flags are passed down to umbrella children

Closes elixir-lang#14852.
Closes elixir-lang#14860.

Author: josevalim

lib/mix/lib/mix/tasks/deps.loadpaths.ex

@@ -141,7 +141,11 @@ defmodule Mix.Tasks.Deps.Loadpaths do
   defp partition([dep | deps], not_ok, compile) do
     cond do
       Mix.Dep.compilable?(dep) or (Mix.Dep.ok?(dep) and local?(dep)) ->
-        partition(deps, not_ok, [dep | compile])
+        if from_umbrella?(dep) do
+          partition(deps, not_ok, compile)
+        else
+          partition(deps, not_ok, [dep | compile])
+        end
 
       Mix.Dep.ok?(dep) ->
         partition(deps, not_ok, compile)
@@ -155,6 +159,14 @@ defmodule Mix.Tasks.Deps.Loadpaths do
     {Enum.reverse(not_ok), Enum.reverse(compile)}
   end
 
+  # Children from the umbrella are compiled sequentially by the umbrella project itself.
+  # We could start compiling them as dependencies, and therefore in parallel, but because
+  # `mix compile` in an umbrella is expected to return the diagnostics of all children,
+  # we would need a pass after compilation to compite diagnostics.
+  defp from_umbrella?(dep) do
+    dep.opts[:from_umbrella]
+  end
+
   defp reload_deps(deps) do
     deps
     |> Enum.map(& &1.app)

lib/mix/test/mix/umbrella_test.exs

@@ -66,7 +66,7 @@ defmodule Mix.UmbrellaTest do
         # Ensure we can compile and run checks
         Mix.Task.run("deps.compile")
         Mix.Task.run("deps.loadpaths")
-        Mix.Task.run("compile", ["--verbose"])
+        Mix.Task.run("compile")
 
         # Extra applications are picked even for umbrellas
         assert :code.where_is_file(~c"runtime_tools.app") != :non_existing
@@ -83,6 +83,13 @@ defmodule Mix.UmbrellaTest do
         assert_received {:mix_shell, :info, [":foo env is dev"]}
         assert_received {:mix_shell, :info, [":bar env is dev"]}
 
+        # Ensure we can compile --force
+        Mix.Task.clear()
+        Mix.Task.run("compile", ["--force"])
+        assert_received {:mix_shell, :info, ["Generated foo app"]}
+        assert_received {:mix_shell, :info, ["Generated bar app"]}
+
+        # Ensure we can start even with --no-compile
         Mix.Task.clear()
         Mix.Task.run("app.start", ["--no-compile"])
       end)
@@ -282,23 +289,6 @@ defmodule Mix.UmbrellaTest do
     end)
   end
 
-  test "compile for umbrella as dependency with os partitions" do
-    System.put_env("MIX_OS_DEPS_COMPILE_PARTITION_COUNT", "2")
-
-    in_fixture("umbrella_dep", fn ->
-      Mix.Project.in_project(:umbrella_dep, ".", fn _ ->
-        output = ExUnit.CaptureIO.capture_io(fn -> Mix.Task.run("compile") end)
-        assert output =~ ~r/\d> :foo env is prod/
-        assert output =~ ~r/\d> :bar env is prod/
-
-        assert_received {:mix_shell, :info, ["mix deps.compile running across 2 OS processes"]}
-        assert Bar.bar() == "hello world"
-      end)
-    end)
-  after
-    System.delete_env("MIX_OS_DEPS_COMPILE_PARTITION_COUNT")
-  end
-
   defmodule CycleDeps do
     def project do
       [