Load plugins on formatter_for_file, closes #12930

Author: josevalim

lib/mix/lib/mix/tasks/format.ex

@@ -306,6 +306,8 @@ defmodule Mix.Tasks.Format do
     {formatter_opts_and_subs, _sources} =
       eval_deps_and_subdirectories(cwd, dot_formatter, formatter_opts, [dot_formatter])
 
+    formatter_opts_and_subs = load_plugins(formatter_opts_and_subs)
+
     find_formatter_and_opts_for_file(Path.expand(file, cwd), formatter_opts_and_subs)
   end
 

lib/mix/test/mix/tasks/format_test.exs

@@ -308,6 +308,24 @@ defmodule Mix.Tasks.FormatTest do
                '''abc
              end
              """
+
+      {formatter_function, _options} = Mix.Tasks.Format.formatter_for_file("a.ex")
+
+      assert formatter_function.("""
+             if true do
+               ~W'''
+               foo bar baz
+               '''abc
+             end
+             """) == """
+             if true do
+               ~W'''
+               foo
+               bar
+               baz
+               '''abc
+             end
+             """
     end)
   end