Change update-w3c-test-expectations to only rebaseline existing tests.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/update_w3c_test_expectations.py

 # Copyright 2016 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.
 
 """A class for updating layout test expectations when updating w3c tests.
 
 Specifically, this class fetches results from try bots for the current CL, and:
   1. Downloads new baseline files for any tests that can be rebaselined.
   2. Updates the generic TestExpectations file for any other failing tests.
 
 This is used as part of the w3c test auto-import process.
 """
 
 import argparse
+import copy
 import logging
 
 from webkitpy.common.net.git_cl import GitCL
 from webkitpy.common.net.rietveld import Rietveld
 from webkitpy.common.webkit_finder import WebKitFinder
 from webkitpy.w3c.test_parser import TestParser
 from webkitpy.layout_tests.models.test_expectations import TestExpectationLine
 
 _log = logging.getLogger(__name__)
 
@@ skipping 269 matching lines @@
         failure test dictionary.
 
         Args:
             tests_results: A dict mapping test name to platform to test results.
 
         Returns:
             An updated tests_results dictionary without the platform-specific
             testharness.js tests that required new baselines to be downloaded
             from `webkit-patch rebaseline-from-try-jobs`.
         """
-        modified_files = self.host.executive.run_command(['git', 'diff', 'origin/master', '--name-only']).splitlines()
-        tests_to_rebaseline, tests_results = self.get_tests_to_rebaseline(modified_files, tests_results)
+        modified_tests = self.get_modified_existing_tests()
+        tests_to_rebaseline, tests_results = self.get_tests_to_rebaseline(modified_tests, tests_results)
         _log.debug('Tests to rebaseline: %r', tests_to_rebaseline)
         if tests_to_rebaseline:
             webkit_patch = self.host.filesystem.join(
                 self.finder.chromium_base(), self.finder.webkit_base(), self.finder.path_to_script('webkit-patch'))
             self.host.executive.run_command([
                 'python',
                 webkit_patch,
                 'rebaseline-cl',
                 '--verbose',
                 '--no-trigger-jobs',
                 '--only-changed-tests',
             ] + tests_to_rebaseline)
         return tests_results
 
-    def get_tests_to_rebaseline(self, modified_files, tests_results):
+    def get_modified_existing_tests(self):
+        """Returns a list of layout test names for layout tests that have been modified."""
+        diff_output = self.host.executive.run_command(
+            ['git', 'diff', 'origin/master', '--name-only', '-diff-filter=AMR'])  # Added, modified, and renamed files.
+        paths_from_chromium_root = diff_output.splitlines()
+        modified_tests = []
+        for path in paths_from_chromium_root:
+            absolute_path = self.host.filesystem.join(self.finder.chromium_base(), path)
+            if not self.host.filesystem.exists(absolute_path):
+                _log.warning('File does not exist: %s', absolute_path)
+                continue
+            test_path = self.finder.layout_test_name(path)
+            if test_path:
+                modified_tests.append(test_path)
+        return modified_tests
+
+    def get_tests_to_rebaseline(self, modified_tests, test_results):
         """Returns a list of tests to download new baselines for.
 
         Creates a list of tests to rebaseline depending on the tests' platform-
         specific results. In general, this will be non-ref tests that failed
         due to a baseline mismatch (rather than crash or timeout).
 
         Args:
-            modified_files: A list of paths to modified files (which should
+            modified_tests: A list of paths to modified files (which should
                 be added, removed or modified files in the imported w3c
-                directory), relative to the Chromium checkout root.
-            tests_results: A dictionary of failing tests results.
+                directory), relative to the LayoutTests directory.
+            test_results: A dictionary of failing tests results.
 
         Returns:
-            A pair: A set of tests to be rebaselined, and an updated
-            tests_results dictionary. These tests to be rebaselined includes
-            both testharness.js tests and ref tests that failed some try job.
+            A pair: A set of tests to be rebaselined, and an modified updated

[jsbell, 2016/10/04 23:43:33]

Grammar: "an modified updated" doesn't make sense

[qyearsley, 2016/10/05 17:20:36]

Gah, thanks for catching :-) The intended change here was to say that instead of
updating the original dictionary and returning it, this now returns a separate
copy based on the original; the reason for this change is because that is what I
expected the behavior should be like originally.

+            test_results dictionary. The tests to be rebaselined should include
+            testharness.js tests that failed due to a baseline mismatch.
         """
+        test_results = copy.deepcopy(test_results)
         tests_to_rebaseline = set()
-        layout_tests_rel_path = self.host.filesystem.relpath(
-            self.finder.layout_tests_dir(), self.finder.chromium_base())
-        for file_path in modified_files:
-            test_path = self.host.filesystem.relpath(file_path, layout_tests_rel_path)
-            if self.is_js_test(test_path) and tests_results.get(test_path):
-                for platform in tests_results[test_path].keys():
-                    if tests_results[test_path][platform]['actual'] not in ['CRASH', 'TIMEOUT']:
-                        del tests_results[test_path][platform]
-                        tests_to_rebaseline.add(test_path)
-        return list(tests_to_rebaseline), tests_results
+        for test_path in modified_tests:
+            if not (self.is_js_test(test_path) and test_results.get(test_path)):
+                continue
+            for platform in test_results[test_path].keys():
+                if test_results[test_path][platform]['actual'] not in ['CRASH', 'TIMEOUT']:
+                    del test_results[test_path][platform]
+                    tests_to_rebaseline.add(test_path)
+        return sorted(tests_to_rebaseline), test_results
 
     def is_js_test(self, test_path):
         """Checks whether a given file is a testharness.js test.
 
         Args:
             test_path: A file path relative to the layout tests directory.
                 This might correspond to a deleted file or a non-test.
         """
         absolute_path = self.host.filesystem.join(self.finder.layout_tests_dir(), test_path)
         test_parser = TestParser(absolute_path, self.host)
         if not test_parser.test_doc:
             return False
         return test_parser.is_jstest()