Merge pull request #409 from samsaggace/master

Fix file stashing with external diff tool

pre_commit/staged_files_only.py

@@ -23,7 +23,7 @@ def staged_files_only(cmd_runner):
     retcode, diff_stdout_binary, _ = cmd_runner.run(
         [
             'git', 'diff', '--ignore-submodules', '--binary', '--exit-code',
-            '--no-color',
+            '--no-color', '--no-ext-diff',
         ],
         retcode=None,
         encoding=None,