Skip commits that don't generate a patch + fixes to get export working

third_party/WebKit/Tools/Scripts/webkitpy/w3c/test_exporter.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.
 
 import logging
 from webkitpy.w3c.local_wpt import LocalWPT
 from webkitpy.w3c.chromium_wpt import ChromiumWPT
 from webkitpy.w3c.chromium_commit import ChromiumCommit
 
 _log = logging.getLogger(__name__)
@@ skipping 17 matching lines @@
             _log.info(pull_request['title'])
 
             # TODO(jeffcarp): Check the PR status here
 
             if self.dry_run:
                 _log.info('[dry_run] Would have attempted to merge PR')
             else:
                 _log.info('Merging...')
                 self.wpt_github.merge_pull_request(pull_request['number'])
                 _log.info('PR merged!')
+                # TODO(jeffcarp): Delete remote branch after merging
+
+            # The script needs to stop here since the Chromium
+            # WPT mirror lags behind a little bit. Also, it's probably safer
+            # to not be merging and creating a PR in the same run.
+            return
         elif len(pull_requests) > 1:
             _log.error(pull_requests)
             # TODO(jeffcarp): Print links to PRs
             raise Exception('More than two in-flight PRs!')
 
         # Second, look for exportable commits in Chromium
         # At this point, no in-flight PRs should exist
         # If there was an issue merging, it should have errored out
-        local_wpt = LocalWPT(self.host, use_github=False)
+        local_wpt = LocalWPT(self.host, use_github=True)
         chromium_wpt = ChromiumWPT(self.host)
 
         # TODO(jeffcarp): have the script running this fetch Chromium origin/master
         # TODO(jeffcarp): move WPT fetch out of its constructor to match planned ChromiumWPT pattern
 
         wpt_commit, chromium_commit = local_wpt.most_recent_chromium_commit()
         assert chromium_commit, 'No Chromium commit found, this is impossible'
 
         wpt_behind_master = local_wpt.commits_behind_master(wpt_commit)
 
         _log.info('\nLast Chromium export commit in web-platform-tests:')
         _log.info('web-platform-tests@%s', wpt_commit)
         _log.info('(%d behind web-platform-tests@origin/master)', wpt_behind_master)
 
         _log.info('\nThe above WPT commit points to the following Chromium commit:')
         _log.info('chromium@%s', chromium_commit.sha)
         _log.info('(%d behind chromium@origin/master)', chromium_commit.num_behind_master())
 
         # TODO(jeffcarp): Have this function return ChromiumCommits
         exportable_commits = chromium_wpt.exportable_commits_since(chromium_commit.sha)
 
+        def has_patch(commit):
+            # TODO(jeffcarp): now do a test comparison of patch against local WPT
+            # TODO(jeffcarp): dedupe from format_patch below
+            outbound_commit = ChromiumCommit(self.host, sha=commit)
+            patch = outbound_commit.format_patch()
+            output = local_wpt.test_patch(patch)
+            return bool(output)
+
+        exportable_commits = filter(has_patch, exportable_commits)
+
         if not exportable_commits:
             _log.info('No exportable commits found in Chromium, stopping.')
             return
 
         _log.info('Found %d exportable commits in Chromium:', len(exportable_commits))
         for commit in exportable_commits:
             _log.info('- %s %s', commit, chromium_wpt.subject(commit))
 
         outbound_commit = ChromiumCommit(self.host, sha=exportable_commits[0])
         _log.info('Picking the earliest commit and creating a PR')
         _log.info('- %s %s', outbound_commit.sha, outbound_commit.subject())
 
         patch = outbound_commit.format_patch()
         message = outbound_commit.message()
 
-        # TODO: now do a test comparison of patch against local WPT
-
         if self.dry_run:
             _log.info('[dry_run] Stopping before creating PR')
             _log.info('\n\n[dry_run] message:')
             _log.info(message)
             _log.info('\n\n[dry_run] patch:')
             _log.info(patch)
             return
 
         local_branch_name = local_wpt.create_branch_with_patch(message, patch)
 
         self.wpt_github.create_pr(
             local_branch_name=local_branch_name,
             desc_title=outbound_commit.subject(),
             body=outbound_commit.body())
+
+        # TODO(jeffcarp): Create a comment on the PR to CC foolip and qyearsley