Bugfixing URL construction for extract build step

scripts/slave/extract_build.py

Index: scripts/slave/extract_build.py
diff --git a/scripts/slave/extract_build.py b/scripts/slave/extract_build.py
index f08fba727d374df40ece3e539995cdb16a0caf88..c48911ab2d4aa473ed5c82bdef148a3d9aa02a0a 100755
--- a/scripts/slave/extract_build.py
+++ b/scripts/slave/extract_build.py
@@ -77,7 +77,7 @@ def GetBuildUrl(abs_build_dir, options):
   replace_dict = dict(options.build_properties)
   # If builddir isn't specified, assume buildbot used the builder name
   # as the root folder for the build.
-  if not replace_dict.get('parent_builddir'):
+  if not replace_dict.get('parent_builddir') and replace_dict.get('parentname'):

[kjellander_chromium, 2012/12/28 16:47:31]

This avoids crashing if an empty build_properties dict is passed, which I think
should be possible.

[Isaac (away), 2013/01/08 08:54:02]

Still might crash because replace_dict wouldn't have parent_builddir and could
fail the string format operation on line 91.  How about instead we change line
81 to have replace_dict.get('parentname', '')

[kjellander_chromium, 2013/01/08 09:32:52]

Good idea. Updated. 
On 2013/01/08 08:54:02, Isaac wrote:

     replace_dict['parent_builddir'] = replace_dict['parentname']
   replace_dict['base_filename'] = base_filename
   url = options.build_url or options.factory_properties.get('build_url')
@@ -85,7 +85,9 @@ def GetBuildUrl(abs_build_dir, options):
     url = ('http://%(parentslavename)s/b/build/slave/%(parent_builddir)s/'
            'chrome_staging')
   if url[-4:] != '.zip': # assume filename not specified
-    url = os.path.join(url, '%(base_filename)s.zip')
+    # Append the filename to the base URL. First strip any trailing slashes.

[kjellander_chromium, 2012/12/28 16:47:31]

Simple way of avoiding double slashes being concatenated into the URL.
urlparse.urljoin cannot be used since it doesn't support gs:// URLs (in addition
to the somewhat complicated way it works).

+    url = url.strip('/')

[Isaac (away), 2013/01/08 08:54:02]

nit, cleaner to use rstrip

[kjellander_chromium, 2013/01/08 09:32:52]

Done.

+    url = '%s/%s' % (url, '%(base_filename)s.zip')
   url = url % replace_dict
 
   versioned_url = url.replace('.zip', version_suffix + '.zip')