W3C test importer: only consider tests to be renamed with 100% similarity.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/deps_updater.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Fetches a copy of the latest state of a W3C test repository and commits.
 
 If this script is given the argument --auto-update, it will also attempt to
 upload a CL, triggery try jobs, and make any changes that are required for
 new failing tests before committing.
 """
@@ skipping 406 matching lines @@
                 # then the original string is used. If the warnings are reset, then the
                 # expectation line is re-serialized when output.
                 expectation_line.warnings = []
                 changed_lines.append(expectation_line)
             new_lines.append(expectation_line)
         new_file_contents = TestExpectations.list_to_string(new_lines, reconstitute_only_these=changed_lines)
         self.host.filesystem.write_text_file(path, new_file_contents)
 
     def _list_deleted_tests(self):
         """Returns a list of layout tests that have been deleted."""
-        out = self.check_run(['git', 'diff', 'origin/master', '--diff-filter=D', '--name-only'])
+        out = self.check_run(['git', 'diff', 'origin/master', '-M100%', '--diff-filter=D', '--name-only'])

[Dirk Pranke, 2016/10/26 17:50:25]

You might want --no-rename instead, I'm not sure if there'll be much of a
difference.

[qyearsley, 2016/10/26 18:00:19]

It looks like the difference is: with --no-renames, even renames with 100%
similarity are considered a delete and add instead of a rename. With -M100%,
simple renames with no change in content are still considered renames, and not
deletions/additions.

Potentially, I could change this to only remove deleted/renamed files from
TestExpectation, and not update them when they're renamed them, and that would
be a little simpler. But, I think it would still be good to keep the behavior of
updating instead of removing expectation lines when there's just a simple rename
with no change in test content.

         deleted_tests = []
         for line in out.splitlines():
             test = self.finder.layout_test_name(line)
             if test:
                 deleted_tests.append(test)
         return deleted_tests
 
     def _list_renamed_tests(self):
         """Returns a dict mapping source to dest name for layout tests that have been renamed."""
-        out = self.check_run(['git', 'diff', 'origin/master', '--diff-filter=R', '--name-status'])
+        out = self.check_run(['git', 'diff', 'origin/master', '-M100%', '--diff-filter=R', '--name-status'])
         renamed_tests = {}
         for line in out.splitlines():
             _, source_path, dest_path = line.split()
             source_test = self.finder.layout_test_name(source_path)
             dest_test = self.finder.layout_test_name(dest_path)
             if source_test and dest_test:
                 renamed_tests[source_test] = dest_test
         return renamed_tests