Properly populate top_level field of deps (#7931)

Closes #7930

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: josevalim

lib/mix/lib/mix/dep.ex

@@ -123,9 +123,12 @@ defmodule Mix.Dep do
 
   defp load_and_cache(config, _top, bottom, _env) do
     {_, deps} = Mix.ProjectStack.read_cache({:cached_deps, bottom})
-    apps = [Keyword.fetch!(config, :app)]
-    seen = populate_seen(MapSet.new(), apps)
-    get_deps(deps, tl(Enum.uniq(get_children(deps, seen, apps))))
+    app = Keyword.fetch!(config, :app)
+    top_level = for dep <- deps, dep.app == app, child <- dep.deps, do: child.app
+
+    seen = populate_seen(MapSet.new(), [app])
+    children = get_deps(deps, tl(Enum.uniq(get_children(deps, seen, [app]))))
+    Enum.map(children, &%{&1 | top_level: &1.app in top_level})
   end
 
   defp read_cached_deps(project, env) do

lib/mix/test/mix/dep_test.exs

@@ -488,6 +488,27 @@ defmodule Mix.DepTest do
     end)
   end
 
+  test "nested deps with no overrides" do
+    # deps_repo brings git_repo but it is overriden
+    deps = [
+      {:deps_repo, "0.1.0", path: "custom/deps_repo"}
+    ]
+
+    with_deps(deps, fn ->
+      in_fixture("deps_status", fn ->
+        File.mkdir_p!("custom/deps_repo/lib")
+
+        File.write!("custom/deps_repo/lib/a.ex", """
+        # Check that the child dependency is top_level
+        [%Mix.Dep{app: :git_repo, top_level: true}] = Mix.Dep.cached()
+        """)
+
+        Mix.Tasks.Deps.Get.run([])
+        Mix.Tasks.Deps.Compile.run([])
+      end)
+    end)
+  end
+
   test "nested deps with overrides" do
     # deps_repo brings git_repo but it is overriden
     deps = [