Blacklist http(s): from being parsed as a git footer

It's unlikely that anyone would ever intend to have a git trailer
whose key is "http", but since URLs are often long, it is rather
likely that someone would put a URL on a line all by itself. When
that happens, don't accidentally interpret it as a footer.

R=iannucci, tandrii

Bug: 766234
Change-Id: I3101119c4e49e20339487618cc1719452b026d90
Reviewed-on: https://chromium-review.googlesource.com/849484
Commit-Queue: Aaron Gable <agable@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>

git_footers.py

@@ -15,6 +15,7 @@ import git_common as git
 
 FOOTER_PATTERN = re.compile(r'^\s*([\w-]+): *(.*)$')
 CHROME_COMMIT_POSITION_PATTERN = re.compile(r'^([\w/\-\.]+)@{#(\d+)}$')
+FOOTER_KEY_BLACKLIST = set(['http', 'https'])
 
 
 def normalize_name(header):
@@ -24,10 +25,9 @@ def normalize_name(header):
 def parse_footer(line):
   """Returns footer's (key, value) if footer is valid, else None."""
   match = FOOTER_PATTERN.match(line)
-  if match:
+  if match and match.group(1) not in FOOTER_KEY_BLACKLIST:
     return (match.group(1), match.group(2))
-  else:
-    return None
+  return None
 
 
 def parse_footers(message):

tests/git_footers_test.py

@@ -89,6 +89,24 @@ My commit message is my best friend. It is my life. I must master it.
                       'For': ['example'],
                       'And-Only-Valid': ['footers taken']})
 
+  def testAvoidingURLs(self):
+    message = ('Someone accidentally put a URL in the footers.\n'
+               '\n'
+               'Followed: by\n'
+               'http://domain.tld\n'
+               'Some: footers')
+    self.assertEqual(git_footers.split_footers(message),
+                     (['Someone accidentally put a URL in the footers.',
+                       ''],
+                      ['Followed: by',
+                       'http://domain.tld',
+                       'Some: footers'],
+                      [('Followed', 'by'),
+                       ('Some', 'footers')]))
+    self.assertEqual(git_footers.parse_footers(message),
+                     {'Followed': ['by'],
+                      'Some': ['footers']})
+
   def testGetFooterChangeId(self):
     msg = '\n'.join(['whatever',
                      '',