webkitpy: Merge script fix windows directory removing.

third_party/WebKit/Tools/Scripts/merge-layout-test-results

 #!/usr/bin/python
 #
 # Copyright 2017 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 argparse
 import json
 import logging
 import os
 import shutil
 import sys
 import tempfile
+import time
 
 from webkitpy.common.system.log_utils import configure_logging
 from webkitpy.layout_tests import merge_results
 
 # ------------------------------------------------------------------------
 
+def rmtree(dirname):
+    # Attempt to remove a directory tree. We try multiple times as on Windows a
+    # process which is currently closing could still have a file open in the
+    # directory.
+    attempts = 0
+    while attempts < 5:
+        try:
+            shutil.rmtree(dirname)
+            break
+        except Exception as e:
+            logging.exception('Failed to remove %s', dirname)
+            time.sleep(1)
+
+    # Check the path is gone.
+    if not os.path.exists(dirname):
+        return True
+
+    logging.warning('Unable to remove %s!', dirname)
+    return False
+
 
 def main(argv):
 
     parser = argparse.ArgumentParser()
     parser.description = """\
 Merges sharded layout test results into a single output directory.
 """
     parser.epilog = """\
 
 If a post merge script is given, it will be run on the resulting merged output
@@ skipping 121 matching lines @@
         except NameError:
             results_json_value_overrides[k] = v
     logging.debug('results_json_value_overrides: %r', results_json_value_overrides)
 
     merger = merge_results.LayoutTestDirMerger(
         results_json_value_overrides=results_json_value_overrides,
         results_json_allow_unknown_if_matching=args.results_json_allow_unknown_if_matching)
     if os.path.exists(args.output_directory):
         logging.warning('Output directory exists %r', args.output_directory)
         if args.remove_existing_output_directory:
-            shutil.rmtree(args.output_directory)
+            rmtree(args.output_directory)

[Dirk Pranke, 2017/05/05 01:05:02]

if you're actually going to ignore the error in the end, why not just pass
ignore_errors=true to shutil.rmtree() ?

         elif not args.allow_existing_output_directory:
             raise IOError(
                 ('Output directory %s exists!\n'
                  'Use --allow-existing-output-directory to continue') % args.output_directory)
 
     merger.merge(args.output_directory, args.input_directories)
 
     merged_output_json = os.path.join(args.output_directory, 'output.json')
     if os.path.exists(merged_output_json) and args.output_json:
         logging.debug(
             'Copying output.json from %s to %s', merged_output_json, args.output_json)
         shutil.copyfile(merged_output_json, args.output_json)
 
     if args.post_merge_script:
         logging.debug('Changing directory to %s', args.output_directory)
         os.chdir(args.output_directory)
 
         post_script = list(args.post_merge_script)
         post_script.append('--result-dir', args.output_directory)
 
         logging.info('Running post merge script %r', post_script)
         os.execlp(post_script)
 
 main(sys.argv[1:])