Issue 2723 - Raise a more detailed exception when there is no update for Mozilla products

globals/get_browser_versions.py

 import re
 import os
 import sys
 import json
 import urllib
 import errno
 import logging
 import time
 from xml.dom import minidom
 
@@ skipping 27 matching lines @@
     origin_version,
     origin_build,
     platform,
     channel
   ))
   try:
     doc = minidom.parse(response)
   finally:
     response.close()
 
-  update = doc.getElementsByTagName('update')[0]
-  full_version = update.getAttribute(attribute)
+  updates = doc.getElementsByTagName('update')
+  if not updates:
+    raise Exception('No updates for %s in %s channel' % (product, channel))
+  full_version = updates[0].getAttribute(attribute)
 
   match = re.search(r'^(\d+)(?:\.\d+)?', full_version)
   if minor:
     return match.group(0)
   return match.group(1)
 
 def get_mozilla_versions(product, origin_version, release_minor=False):
   return {
     'current': get_mozilla_version(product, origin_version, 'release', release_minor),
     'unreleased': [
@@ skipping 169 matching lines @@
     file.seek(0)
     json.dump(persistent_cache, file)
     file.truncate()
 
   if not versions['previous']:
     logging.warning("Couldn't determine previous browser version, "
                     'please set %s.previous in %s', browser, filename)
 
   cache[browser] = versions
   return versions