Fix KeyError caused when filtering gtests on multiple threads.

build/android/pylib/gtest/gtest_test_instance.py

 # Copyright 2014 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 HTMLParser
 import logging
 import os
 import re
 import tempfile
+import threading
 import xml.etree.ElementTree
 
 from devil.android import apk_helper
 from pylib import constants
 from pylib.constants import host_paths
 from pylib.base import base_test_result
 from pylib.base import test_instance
 from pylib.utils import isolator
 
 with host_paths.SysPath(host_paths.BUILD_COMMON_PATH):
@@ skipping 213 matching lines @@
   def __init__(self, args, isolate_delegate, error_func):
     super(GtestTestInstance, self).__init__()
     # TODO(jbudorick): Support multiple test suites.
     if len(args.suite_name) > 1:
       raise ValueError('Platform mode currently supports only 1 gtest suite')
     self._exe_dist_dir = None
     self._extract_test_list_from_filter = args.extract_test_list_from_filter
     self._shard_timeout = args.shard_timeout
     self._store_tombstones = args.store_tombstones
     self._suite = args.suite_name[0]
+    self._filter_tests_lock = threading.Lock()
 
     # GYP:
     if args.executable_dist_dir:
       self._exe_dist_dir = os.path.abspath(args.executable_dist_dir)
     else:
       # TODO(agrieve): Remove auto-detection once recipes pass flag explicitly.
       exe_dist_dir = os.path.join(constants.GetOutDirectory(),
                                   '%s__dist' % self._suite)
 
       if os.path.exists(exe_dist_dir):
@@ skipping 168 matching lines @@
         DISABLED_, FLAKY_, FAILS_, PRE_, and MANUAL_
     Returns:
       A filtered list of tests to run.
     """
     gtest_filter_strings = [
         self._GenerateDisabledFilterString(disabled_prefixes)]
     if self._gtest_filter:
       gtest_filter_strings.append(self._gtest_filter)
 
     filtered_test_list = test_list
-    for gtest_filter_string in gtest_filter_strings:
-      logging.debug('Filtering tests using: %s', gtest_filter_string)
-      filtered_test_list = unittest_util.FilterTestNames(
-          filtered_test_list, gtest_filter_string)
+    # This lock is required because on older versions of Python
+    # |unittest_util.FilterTestNames| use of |fnmatch| is not threadsafe.
+    with self._filter_tests_lock:
+      for gtest_filter_string in gtest_filter_strings:
+        logging.debug('Filtering tests using: %s', gtest_filter_string)
+        filtered_test_list = unittest_util.FilterTestNames(
+            filtered_test_list, gtest_filter_string)
     return filtered_test_list
 
   def _GenerateDisabledFilterString(self, disabled_prefixes):
     disabled_filter_items = []
 
     if disabled_prefixes is None:
       disabled_prefixes = ['DISABLED_', 'FLAKY_', 'FAILS_', 'PRE_', 'MANUAL_']
     disabled_filter_items += ['%s*' % dp for dp in disabled_prefixes]
     disabled_filter_items += ['*.%s*' % dp for dp in disabled_prefixes]
 
     disabled_tests_file_path = os.path.join(
         host_paths.DIR_SOURCE_ROOT, 'build', 'android', 'pylib', 'gtest',
         'filter', '%s_disabled' % self._suite)
     if disabled_tests_file_path and os.path.exists(disabled_tests_file_path):
       with open(disabled_tests_file_path) as disabled_tests_file:
         disabled_filter_items += [
             '%s' % l for l in (line.strip() for line in disabled_tests_file)
             if l and not l.startswith('#')]
 
     return '*-%s' % ':'.join(disabled_filter_items)
 
   #override
   def TearDown(self):
     """Clear the mappings created by SetUp."""
     if self._isolate_delegate:
       self._isolate_delegate.Clear()