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

third_party/WebKit/Tools/Scripts/webkitpy/w3c/local_wpt.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 utility class for interacting with a local checkout of the Web Platform Tests."""
 
 import logging
 
 from webkitpy.w3c.chromium_commit import ChromiumCommit
+from webkitpy.common.system.executive import ScriptError
 
 WPT_REPO_URL = 'https://chromium.googlesource.com/external/w3c/web-platform-tests.git'
 WPT_TMP_DIR = '/tmp/wpt'
 CHROMIUM_WPT_DIR = 'third_party/WebKit/LayoutTests/imported/wpt/'
 
 _log = logging.getLogger(__name__)
 
 
 class LocalWPT(object):
 
-    def __init__(self, host, path=WPT_TMP_DIR, no_fetch=False, use_github=False):
+    def __init__(self, host, path=WPT_TMP_DIR, no_fetch=False):
         """
         Args:
             host: A Host object.
             path: Optional, the directory where LocalWPT will check out web-platform-tests.
             no_fetch: Optional, passing true will skip updating the local WPT.
                 Intended for use only in development after fetching once.
-            use_github: Optional, passing true will check if the GitHub remote is enabled
-                (necessary for later pull request steps).
         """
         self.host = host
         self.path = path
+        self.branch_name = 'chromium-export-try'
 
         if no_fetch:
             _log.info('Skipping remote WPT fetch')
             return
 
         if self.host.filesystem.exists(self.path):
             _log.info('WPT checkout exists at %s, fetching latest', self.path)
-            self.run(['git', 'fetch', '--all'])
+            self.run(['git', 'fetch', 'origin'])
             self.run(['git', 'checkout', 'origin/master'])
         else:
             _log.info('Cloning %s into %s', WPT_REPO_URL, self.path)
             self.host.executive.run_command(['git', 'clone', WPT_REPO_URL, self.path])
 
-        if use_github and 'github' not in self.run(['git', 'remote']):
-            raise Exception('Need to set up remote "github"')
-
     def run(self, command, **kwargs):
         """Runs a command in the local WPT directory."""
         return self.host.executive.run_command(command, cwd=self.path, **kwargs)
 
     def most_recent_chromium_commit(self):
         """Finds the most recent commit in WPT with a Chromium commit position."""
         sha = self.run(['git', 'rev-list', 'HEAD', '-n', '1', '--grep=Cr-Commit-Position'])
         if not sha:
             return None, None
 
         sha = sha.strip()
         position = self.run(['git', 'footers', '--position', sha])
         position = position.strip()
         assert position
 
         chromium_commit = ChromiumCommit(self.host, position=position)
         return sha, chromium_commit
 
     def clean(self):
         self.run(['git', 'reset', '--hard', 'HEAD'])
         self.run(['git', 'clean', '-fdx'])
         self.run(['git', 'checkout', 'origin/master'])
+        try:
+            self.run(['git', 'branch', '-D', self.branch_name])
+        except ScriptError:
+            _log.info('Local branch %s does not exist yet, not deleting', self.branch_name)
 
     def all_branches(self):
         """Returns a list of local and remote branches."""
         return self.run(['git', 'branch', '-a']).splitlines()
 
     def create_branch_with_patch(self, message, patch):
         """Commits the given patch and pushes to the upstream repo.
 
         Args:
             message: Commit message string.
             patch: A patch that can be applied by git apply.
         """
         self.clean()
         all_branches = self.all_branches()
-        branch_name = 'chromium-export-try'
-        remote_branch_name = 'remotes/github/%s' % branch_name
 
-        if branch_name in all_branches:
-            _log.info('Local branch %s already exists, deleting', branch_name)
-            self.run(['git', 'branch', '-D', branch_name])
+        # Creating and deleting the branch causes a bunch of
+        # noise in the #testing channel - trying out using
+        # git push -f below to overwrite the branch
 
-        if remote_branch_name in all_branches:
-            _log.info('Remote branch %s already exists, deleting', branch_name)
-            # TODO(jeffcarp): Investigate what happens when remote branch exists.
-            self.run(['git', 'push', 'github', ':{}'.format(branch_name)])
+        # remote_branch_name = 'remotes/github/%s' % self.branch_name
+        # if remote_branch_name in all_branches:
+        #     _log.info('Remote branch %s already exists, deleting', remote_branch_name)
+        #     # TODO(jeffcarp): Investigate what happens when remote branch exists.
+        #     self.run(['git', 'push', 'github', ':{}'.format(remote_branch_name)])
 
-        _log.info('Creating local branch %s', branch_name)
-        self.run(['git', 'checkout', '-b', branch_name])
+        _log.info('Creating local branch %s', self.branch_name)
+        self.run(['git', 'checkout', '-b', self.branch_name])
 
         # Remove Chromium WPT directory prefix.
         patch = patch.replace(CHROMIUM_WPT_DIR, '')
 
         # TODO(jeffcarp): Use git am -p<n> where n is len(CHROMIUM_WPT_DIR.split(/'))
         # or something not off-by-one.
         self.run(['git', 'apply', '-'], input=patch)
-        self.run(['git', 'commit', '-am', message])
-        self.run(['git', 'push', 'github', branch_name])
+        self.run(['git', 'add', '.'])
+        self.run(['git', 'commit', '-m', message])
+        self.run(['git', 'push', '-f', 'github', self.branch_name])
 
-        return branch_name
+        return self.branch_name
+
+    def test_patch(self, patch):
+        """Returns the expected output of a patch agains origin/master.
+
+        Args:
+            patch: The patch to test against.
+
+        Returns:
+            A string containing the diff the patch produced.
+        """
+        self.clean()
+
+        # Remove Chromium WPT directory prefix.
+        # TODO(jeffcarp): dedupe
+        patch = patch.replace(CHROMIUM_WPT_DIR, '')
+
+        try:
+            self.run(['git', 'apply', '-'], input=patch)
+            self.run(['git', 'add', '.'])
+            output = self.run(['git', 'diff', 'origin/master'])
+        except ScriptError as error:
+            _log.error('Error while applying patch: %s', error)
+            output = ''
+
+        self.clean()
+        return output
 
     def commits_behind_master(self, commit):
         """Returns the number of commits after the given commit on origin/master.
 
         This doesn't include the given commit, and this assumes that the given
         commit is on the the master branch.
         """
         return len(self.run([
             'git', 'rev-list', '{}..origin/master'.format(commit)
         ]).splitlines())