Do not exclude the last revision in the range returned by gitiles.

scripts/slave/recipe_modules/auto_bisect/bisector.py

 # Copyright 2015 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 json
 import re
 import time
 import urllib
 
 from . import config_validation
@@ skipping 359 matching lines @@
   def _expand_initial_revision_range(self):
     """Sets the initial contents of |self.revisions|."""
     with self.api.m.step.nest('Expanding revision range'):
       good_hash = self.good_rev.commit_hash
       bad_hash = self.bad_rev.commit_hash
       step_name = 'for revisions %s:%s' % (good_hash, bad_hash)
       revisions = self._revision_range(
           start=good_hash,
           end=bad_hash,
           depot_name=self.base_depot,
-          step_name=step_name)
+          step_name=step_name,
+          exclude_end=True)
       self.revisions = [self.good_rev] + revisions + [self.bad_rev]
       self._update_revision_list_indexes()
 
   def _revision_range(self, start, end, depot_name, base_revision=None,
-                      step_name=None):
+                      step_name=None, exclude_end=False):
     """Returns a list of RevisionState objects between |start| and |end|.
 
+    When expanding the initial revision range we want to exclude the last
+    revision, since both good and bad have already been created and tested.
+    When bisecting into a roll on the other hand, we want to include the last
+    revision in the roll, because although the code should be equivalent to
+    the roll, we want to blame the right culprit and not the roll.
+
     Args:
       start (str): Start commit hash.
       end (str): End commit hash.
       depot_name (str): Short string name of repo, e.g. chromium or v8.
       base_revision (str): Base revision in the downstream repo (e.g. chromium).
       step_name (str): Optional step name.
+      exclude_end (bool): Whether to exclude the last revision in the range,
+          i.e. the revision given as end.
 
     Returns:
-      A list of RevisionState objects, not including the given start or end.
+      A list of RevisionState objects.
     """
     if self.internal_bisect:  # pragma: no cover
       return self._revision_range_with_gitiles(
           start, end, depot_name, base_revision, step_name)
     try:
       step_result = self.api.m.python(
           step_name,
           self.api.resource('fetch_intervening_revisions.py'),
           [start, end, depot_config.DEPOT_DEPS_NAME[depot_name]['url']],
           stdout=self.api.m.json.output())
     except self.api.m.step.StepFailure:  # pragma: no cover
       self.surface_result('BAD_REV')
       raise
     revisions = []
-    for commit_hash, _ in step_result.stdout:
+    revision_hashes = step_result.stdout
+    if exclude_end:
+      revision_hashes = revision_hashes[:-1]
+    for commit_hash, _ in revision_hashes:
       revisions.append(self.revision_class(
           bisector=self,
           commit_hash=commit_hash,
           depot_name=depot_name,
           base_revision=base_revision))
     return revisions
 
   def _revision_range_with_gitiles(self, start, end, depot_name,
        base_revision=None, step_name=None):   # pragma: no cover
     """Returns a list of RevisionState objects between |start| and |end|.
@@ skipping 524 matching lines @@
         })
     return revision_rows
 
   def _get_build_url(self):
     properties = self.api.m.properties
     bot_url = properties.get('buildbotURL',
                              'http://build.chromium.org/p/chromium/')
     builder_name = urllib.quote(properties.get('buildername', ''))
     builder_number = str(properties.get('buildnumber', ''))
     return '%sbuilders/%s/builds/%s' % (bot_url, builder_name, builder_number)