rebaseline.py: fix --add-new when there are no expectations at all

tools/rebaseline.py

 #!/usr/bin/python
 
 '''
 Copyright 2012 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 '''
 
 '''
@@ skipping 76 matching lines @@
     'Test-Win7-ShuttleA-HD2000-x86-Release',
     'Test-Win7-ShuttleA-HD2000-x86-Release-ANGLE',
     'Test-Win7-ShuttleA-HD2000-x86-Release-DirectWrite',
     'Test-Win7-ShuttleA-HD2000-x86_64-Debug',
     'Test-Win7-ShuttleA-HD2000-x86_64-Release',
 ]
 
 class _InternalException(Exception):
   pass
 
-# Object that handles exceptions, either raising them immediately or collecting
-# them to display later on.
 class ExceptionHandler(object):
+  """ Object that handles exceptions, either raising them immediately or
+  collecting them to display later on."""
 
   # params:
-  #  keep_going_on_failure: if False, report failures and quit right away;
-  #                         if True, collect failures until
-  #                         ReportAllFailures() is called
   def __init__(self, keep_going_on_failure=False):
+    """
+    params:
+      keep_going_on_failure: if False, report failures and quit right away;
+                             if True, collect failures until
+                             ReportAllFailures() is called
+    """
     self._keep_going_on_failure = keep_going_on_failure
     self._failures_encountered = []
-    self._exiting = False
 
-  # Exit the program with the given status value.
-  def _Exit(self, status=1):
-    self._exiting = True
-    sys.exit(status)
-
-  # We have encountered an exception; either collect the info and keep going,
-  # or exit the program right away.
-  def RaiseExceptionOrContinue(self, e):
-    # If we are already quitting the program, propagate any exceptions
-    # so that the proper exit status will be communicated to the shell.
-    if self._exiting:
-      raise e
+  def RaiseExceptionOrContinue(self):
+    """ We have encountered an exception; either collect the info and keep
+    going, or exit the program right away."""
+    # Get traceback information about the most recently raised exception.
+    exc_info = sys.exc_info()
 
     if self._keep_going_on_failure:
-      print >> sys.stderr, 'WARNING: swallowing exception %s' % e
-      self._failures_encountered.append(e)
+      print >> sys.stderr, ('WARNING: swallowing exception %s' %
+                            repr(exc_info[1]))
+      self._failures_encountered.append(exc_info)
     else:
-      print >> sys.stderr, e
       print >> sys.stderr, (
           'Halting at first exception; to keep going, re-run ' +
           'with the --keep-going-on-failure option set.')
-      self._Exit()
+      raise exc_info[1], None, exc_info[2]
 
   def ReportAllFailures(self):
     if self._failures_encountered:
       print >> sys.stderr, ('Encountered %d failures (see above).' %
                             len(self._failures_encountered))
-      self._Exit()
+      sys.exit(1)
 
 
 # Object that rebaselines a JSON expectations file (not individual image files).
 class JsonRebaseliner(object):
 
   # params:
   #  expectations_root: root directory of all expectations JSON files
   #  expectations_input_filename: filename (under expectations_root) of JSON
   #                               expectations file to read; typically
   #                               "expected-results.json"
@@ skipping 117 matching lines @@
     sections = [gm_json.JSONKEY_ACTUALRESULTS_FAILED]
     if self._add_new:
       sections.append(gm_json.JSONKEY_ACTUALRESULTS_NOCOMPARISON)
     results_to_update = self._GetActualResults(json_url=actuals_url,
                                                sections=sections)
 
     # Read in current expectations.
     expectations_input_filepath = os.path.join(
         self._expectations_root, builder, self._expectations_input_filename)
     expectations_dict = gm_json.LoadFromFile(expectations_input_filepath)
-    expected_results = expectations_dict[gm_json.JSONKEY_EXPECTEDRESULTS]
+    expected_results = expectations_dict.get(gm_json.JSONKEY_EXPECTEDRESULTS)
+    if not expected_results:
+      expected_results = {}
+      expectations_dict[gm_json.JSONKEY_EXPECTEDRESULTS] = expected_results
 
     # Update the expectations in memory, skipping any tests/configs that
     # the caller asked to exclude.
     skipped_images = []
     if results_to_update:
       for (image_name, image_results) in results_to_update.iteritems():
         (test, config) = self._image_filename_re.match(image_name).groups()
         if self._tests:
           if test not in self._tests:
             skipped_images.append(image_name)
@@ skipping 37 matching lines @@
 parser.add_argument('--actuals-base-url',
                     help=('base URL from which to read files containing JSON '
                           'summaries of actual GM results; defaults to '
                           '%(default)s'),
                     default='http://skia-autogen.googlecode.com/svn/gm-actual')
 parser.add_argument('--actuals-filename',
                     help=('filename (within builder-specific subdirectories '
                           'of ACTUALS_BASE_URL) to read a summary of results '
                           'from; defaults to %(default)s'),
                     default='actual-results.json')
-# TODO(epoger): Add test that exercises --add-new argument.
 parser.add_argument('--add-new', action='store_true',
                     help=('in addition to the standard behavior of '
                           'updating expectations for failing tests, add '
                           'expectations for tests which don\'t have '
                           'expectations yet.'))
 parser.add_argument('--bugs', metavar='BUG', type=int, nargs='+',
                     help=('Skia bug numbers (under '
                           'https://code.google.com/p/skia/issues/list ) which '
                           'pertain to this set of rebaselines.'))
 parser.add_argument('--builders', metavar='BUILDER', nargs='+',
@@ skipping 66 matching lines @@
         expectations_output_filename=(args.expectations_filename_output or
                                       args.expectations_filename),
         tests=args.tests, configs=args.configs,
         actuals_base_url=args.actuals_base_url,
         actuals_filename=args.actuals_filename,
         exception_handler=exception_handler,
         add_new=args.add_new, bugs=args.bugs, notes=args.notes,
         mark_unreviewed=args.unreviewed)
     try:
       rebaseliner.RebaselineSubdir(builder=builder)
-    except BaseException as e:
-      exception_handler.RaiseExceptionOrContinue(e)
+    except:
+      exception_handler.RaiseExceptionOrContinue()
   else:
-    exception_handler.RaiseExceptionOrContinue(_InternalException(
-        'expectations_json_file %s not found' % expectations_json_file))
+    try:
+      raise _InternalException('expectations_json_file %s not found' %
+                               expectations_json_file)
+    except:
+      exception_handler.RaiseExceptionOrContinue()
 
 exception_handler.ReportAllFailures()