Fetch retry summary and use it to determine what tests to rebaseline.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.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 command to fetch new baselines from try jobs for a Rietveld issue.
 
 This command interacts with the Rietveld API to get information about try jobs
 with layout test results.
 """
 
+import json
 import logging
 import optparse
 
 from webkitpy.common.net.rietveld import Rietveld
 from webkitpy.common.net.web import Web
 from webkitpy.common.net.git_cl import GitCL
 from webkitpy.common.webkit_finder import WebKitFinder
 from webkitpy.layout_tests.models.test_expectations import BASELINE_SUFFIX_LIST
 from webkitpy.tool.commands.rebaseline import AbstractParallelRebaselineCommand
 
@@ skipping 155 matching lines @@
         builds = self.rietveld.latest_try_jobs(issue_number, self._try_bots())
         if not builds:
             _log.debug('No try job results for builders in: %r.', self._try_bots())
         return {build: self._tests_to_rebaseline(build) for build in builds}
 
     def _try_bots(self):
         """Returns a collection of try bot builders to fetch results for."""
         return self._tool.builders.all_try_builder_names()
 
     def _tests_to_rebaseline(self, build):
-        """Fetches a list of LayoutTestResult objects for unexpected results with new baselines."""
+        """Fetches a list of tests that should be rebaselined."""
         buildbot = self._tool.buildbot
         results_url = buildbot.results_url(build.builder_name, build.build_number)
         layout_test_results = buildbot.fetch_layout_test_results(results_url)
         if layout_test_results is None:
             _log.warning('Failed to request layout test results from "%s".', results_url)
             return []
         failure_results = layout_test_results.unexpected_mismatch_results()
         missing_results = layout_test_results.missing_results()
-        return sorted(r.test_name() for r in failure_results + missing_results)
+        tests = sorted(r.test_name() for r in failure_results + missing_results)
+
+        new_failures = self._fetch_tests_with_new_failures(build)
+        if new_failures is None:
+            _log.warning('No retry summary available for build %s.', build)
+        else:
+            tests = [t for t in tests if t in new_failures]
+        return tests
+
+    def _fetch_tests_with_new_failures(self, build):
+        """Fetches a list of tests that failed with a patch in a given try job but not without."""
+        buildbot = self._tool.buildbot
+        content = buildbot.fetch_retry_summary_json(build)
+        if content is None:
+            return None
+        try:
+            retry_summary = json.loads(content)
+            return retry_summary['failures']
+        except (ValueError, KeyError):
+            _log.warning('Unexepected retry summary content:\n%s', content)
+            return None
 
     @staticmethod
     def _log_test_prefix_list(test_prefix_list):
         """Logs the tests to download new baselines for."""
         if not test_prefix_list:
             _log.info('No tests to rebaseline; exiting.')
             return
-        _log.info('Tests to rebaseline:')
+        _log.debug('Tests to rebaseline:')
         for test, builds in test_prefix_list.iteritems():
-            builds_str = ', '.join(sorted('%s (%s)' % (b.builder_name, b.build_number) for b in builds))
-            _log.info('  %s: %s', test, builds_str)
+            _log.debug('  %s:', test)
+            for build in sorted(builds):
+                _log.debug('    %s', build)