bisect_builds: Also print the corresponding webkit revision range.

tools/bisect-builds.py

 #!/usr/bin/python
 # Copyright (c) 2011 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.
 
 """Snapshot Build Bisect Tool
 
 This script bisects a snapshot archive using binary search. It starts at
 a bad revision (it will try to guess HEAD) and asks for a last known-good
 revision. It will then binary search across this revision range by downloading,
 unzipping, and opening Chromium for you. After testing the specific revision,
 it will ask you whether it is good or bad before continuing the search.
 """
 
 # The root URL for storage.
 BASE_URL = 'http://commondatastorage.googleapis.com/chromium-browser-snapshots'
 
 # URL to the ViewVC commit page.
 BUILD_VIEWVC_URL = 'http://src.chromium.org/viewvc/chrome?view=rev&revision=%d'
 
 # Changelogs URL.
 CHANGELOG_URL = 'http://build.chromium.org/f/chromium/' \
                 'perf/dashboard/ui/changelog.html?url=/trunk/src&range=%d:%d'
 
+# DEPS file URL.
+DEPS_FILE= 'http://src.chromium.org/viewvc/chrome/trunk/src/DEPS?revision=%d'
+
+# WebKit Changelogs URL.
+WEBKIT_CHANGELOG_URL = 'http://trac.webkit.org/log/' \
+                       'trunk/?rev=%d&stop_rev=%d&verbose=on'
+
 ###############################################################################
 
 import math
 import optparse
 import os
 import pipes
 import re
 import shutil
 import subprocess
 import sys
@@ skipping 382 matching lines @@
           os.unlink(f)
         except OSError:
           pass
       sys.exit(0)
 
     rev = revlist[pivot]
 
   return (revlist[good], revlist[bad])
 
 
+def GetWebKitRevisionForChromiumRevision(rev):
+  """Returns the webkit revision that was in chromium's DEPS file at
+  chromium revision |rev|."""
+  # . doesn't match newlines without re.DOTALL, so this is safe.
+  webkit_re = re.compile(r'webkit_revision.:\D*(\d+)')
+  url = urllib.urlopen(DEPS_FILE % rev)
+  m = webkit_re.search(url.read())
+  url.close()
+  if m:
+    return int(m.group(1))
+  else:
+    raise Exception('Could not get webkit revision for cr rev %d' % rev)
+
+
 def main():
   usage = ('%prog [options] [-- chromium-options]\n'
            'Perform binary search on the snapshot builds.\n'
            '\n'
            'Tip: add "-- --no-first-run" to bypass the first run prompts.')
   parser = optparse.OptionParser(usage=usage)
   # Strangely, the default help output doesn't include the choice list.
   choices = ['mac', 'win', 'linux', 'linux64']
             # linux-chromiumos lacks a continuous archive http://crbug.com/78158
   parser.add_option('-a', '--archive',
@@ skipping 48 matching lines @@
   else:
     good_rev = 0
     try:
       good_rev = int(raw_input('Last known good [0]: '))
     except Exception, e:
       pass
 
   (last_known_good_rev, first_known_bad_rev) = Bisect(
       opts.archive, good_rev, bad_rev, args, opts.profile)
 
+  # Get corresponding webkit revisions.
+  try:
+    last_known_good_webkit_rev = GetWebKitRevisionForChromiumRevision(
+        last_known_good_rev)
+    first_known_bad_webkit_rev = GetWebKitRevisionForChromiumRevision(
+        first_known_bad_rev)
+  except Exception, e:
+    # Silently ignore the failure.
+    last_known_good_webkit_rev, first_known_bad_webkit_rev = 0, 0
+
   # We're done. Let the user know the results in an official manner.
   print('You are probably looking for build %d.' % first_known_bad_rev)
-  print('CHANGELOG URL:')
-  print(CHANGELOG_URL % (last_known_good_rev, first_known_bad_rev))
-  print('Built at revision:')
-  print(BUILD_VIEWVC_URL % first_known_bad_rev)
+  if last_known_good_webkit_rev != first_known_bad_webkit_rev:
+    print 'WEBKIT CHANGELOG URL:'
+    print WEBKIT_CHANGELOG_URL % (first_known_bad_webkit_rev,
+                                  last_known_good_webkit_rev)
+  print 'CHANGELOG URL:'
+  print CHANGELOG_URL % (last_known_good_rev, first_known_bad_rev)
+  print 'Built at revision:'
+  print BUILD_VIEWVC_URL % first_known_bad_rev
 
 if __name__ == '__main__':
   sys.exit(main())