AttributeError: 'NoneType' object has no attribute 'id'

[Ryan J Ollos]

From the logs:

2016-02-15 08:54:59,277 Trac[api] WARNING: HTML preview using WikiTextRenderer failed: 
Traceback (most recent call last):
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/mimeview/api.py", line 802, in render
    rendered_content, filename, url)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/mimeview/api.py", line 1225, in render
    content_to_unicode(self.env, content, mimetype))
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/wiki/formatter.py", line 1580, in format_to_html
    return HtmlFormatter(env, context, wikidom).generate(escape_newlines)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/wiki/formatter.py", line 1535, in generate
    escape_newlines)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/wiki/formatter.py", line 1317, in format
    result = re.sub(self.wikiparser.rules, self.replace, line)
  File "/usr/lib/python2.7/re.py", line 151, in sub
    return _compile(pattern, flags).sub(repl, string, count)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/wiki/formatter.py", line 1235, in replace
    replacement = self.handle_match(fullmatch)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/wiki/formatter.py", line 1228, in handle_match
    return external_handler(self, match, fullmatch)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/versioncontrol/web_ui/changeset.py", line 1040, in <lambda>
    y, z))
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/versioncontrol/web_ui/changeset.py", line 1064, in _format_changeset_link
    reponame = rm.get_default_repository(formatter.context)
  File "/usr/local/virtualenv/1.0-stable/lib/python2.7/site-packages/trac/versioncontrol/api.py", line 639, in get_default_repository
    return context.resource.parent.id
AttributeError: 'NoneType' object has no attribute 'id'

[Ryan J Ollos]

I'm unsure how this scenario can occur. It's a wiki rendering context with the realm either browser or changeset. The following change would protect against AttributeError:

trac/versioncontrol/api.py

@@ -646 +646 @@
         hierarchy and return the name of its associated repository.
         """
         while context:
-            if context.resource.realm in ('source', 'changeset'):
+            if context.resource.realm in ('source', 'changeset') and \
+                    context.resource.parent:
                 return context.resource.parent.id
             context = context.parent
 

[Ryan J Ollos]

Committed to 1.0-stable in [14777], merged to trunk in [14778].