Added separate checkout and config file generation to bisect script

build/util/PRESUBMIT.py

Index: build/util/PRESUBMIT.py
diff --git a/build/util/PRESUBMIT.py b/build/util/PRESUBMIT.py
new file mode 100644
index 0000000000000000000000000000000000000000..b5685ac625915d8484322866b4054a2dfa044c1c
--- /dev/null
+++ b/build/util/PRESUBMIT.py
@@ -0,0 +1,50 @@
+# Copyright (c) 2013 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.
+
+"""Top-level presubmit script for testing.

[tonyg, 2013/02/14 23:30:06]

Comment needs updating

[shatch, 2013/02/14 23:59:46]

Done.

+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
+details on the presubmit API built into gcl.
+"""
+
+import imp
+
+def _ExamineBisectConfigFile(input_api, output_api):
+  for f in input_api.AffectedFiles():
+    if not f.LocalPath().endswith('run-bisect-perf-regression.cfg'):
+      continue
+
+    try:
+      cfg_file = imp.load_source('config', 'run-bisect-perf-regression.cfg')
+
+      valid_keys = ['command', 'good_revision', 'bad_revision', 'metric']

[tonyg, 2013/02/14 23:30:06]

I'm not sure I'd lock down the key names. We might add a new argument in the
future and it would be totally valid to submit that.

[shatch, 2013/02/14 23:59:46]

If you added a new key name, would you not want PRESUBMIT.py updated with it?

+
+      for k, v in cfg_file.config.iteritems():
+        if not k in valid_keys or v:
+          return f.LocalPath()
+    except (IOError, AttributeError, TypeError):
+      return f.LocalPath()
+
+  return None
+
+def _CheckNoChangesToBisectConfigFile(input_api, output_api):
+  results = _ExamineBisectConfigFile(input_api, output_api)
+  if results:
+    return [output_api.PresubmitError(

[shatch, 2013/02/14 23:00:34]

Should this be just a warning or an error?

[tonyg, 2013/02/14 23:30:06]

error sounds good

+        'The bisection config file should only contain a config dict with '
+        'empty fields. Changes to this file should never be submitted.',
+        items=[results])]
+
+  return []
+
+def CommonChecks(input_api, output_api):
+  results = []
+  results.extend(_CheckNoChangesToBisectConfigFile(input_api, output_api))
+  return results
+
+def CheckChangeOnUpload(input_api, output_api):
+  return CommonChecks(input_api, output_api)

[tonyg, 2013/02/14 23:30:06]

I'm not sure I'd perform this check on upload. Just on commit.

[shatch, 2013/02/14 23:59:46]

I'm a little unfamiliar with the PRESUBMIT scripts, but since
CheckChangeOnUpload covers the 'git cl upload' case, wouldn't you want to throw
out an error in that event too?

+
+def CheckChangeOnCommit(input_api, output_api):
+  return CommonChecks(input_api, output_api)