TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

[anonymous]

Internal Error occurred when I added follow strings in wiki pages.

[[//a ] ]]

Most recent call last:

File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/templates/wiki_edit.html", line 136, in <Expression u'wiki_to_html(context(page.resource), page.text)'>
  ${wiki_to_html(context(page.resource), page.text)}
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 1501, in format_to_html
  return HtmlFormatter(env, context, wikidom).generate(escape_newlines)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 1456, in generate
  escape_newlines)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 1243, in format
  result = re.sub(self.wikiparser.rules, self.replace, line)
File "/var/service/python-2.6.6/lib/python2.6/re.py", line 151, in sub
  return _compile(pattern, 0).sub(repl, string, count)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 1161, in replace
  replacement = self.handle_match(fullmatch)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 1157, in handle_match
  return internal_handler(match, fullmatch)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 709, in _macrolink_formatter
  return self._lhref_formatter(match, fullmatch)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 540, in _lhref_formatter
  return self._make_lhref_link(match, fullmatch, rel, ns, target, label)
File "/var/service/python-2.6.6/lib/python2.6/site-packages/trac/wiki/formatter.py", line 546, in _make_lhref_link
  label = ns + ':' + target   #  use `http://target`

System Information:

• Trac 0.12.3.ja2
• Babel 0.9.5
• Genshi 0.6
• Python 2.6.6 (r266:84292, Mar 1 2011, 20:55:51) [GCC 4.1.2 20080704 (Red Hat 4.1.2-48)]

We create the following patch as a provisional, and have applied it.

src/trac/wiki/formatter.py

@@ -542 +542 @@
     def _make_lhref_link(self, match, fullmatch, rel, ns, target, label):
         if not label: # e.g. `[http://target]` or `[wiki:target]`
             if target:
-                if target.startswith('//'):     # for `[http://target]`
+                if ns and target.startswith('//'):     # for `[http://target]`
                     label = ns + ':' + target   #  use `http://target`
                 else:                           # for `wiki:target`
                     label = target.lstrip('/')  #  use only `target`

[Jun Omae]

Thanks for the reporting! Reproduced with Trac 0.12.7 and 1.0.9.

[Ryan J Ollos]

It's a pretty strange edge case. I'm not very familiar with the formatter.py code though, so maybe someone else could review before I commit.

trac/wiki/formatter.py

@@ -616 +616 @@
     def _make_lhref_link(self, match, fullmatch, rel, ns, target, label):
         if not label: # e.g. `[http://target]` or `[wiki:target]`
             if target:
-                if target.startswith('//'):     # for `[http://target]`
+                if ns and target.startswith('//'):     # for `[http://target]`
                     label = ns + ':' + target   #  use `http://target`
                 else:                           # for `wiki:target`
                     label = target.lstrip('/')  #  use only `target`

trac/wiki/tests/wiki-tests.txt

@@ -363 +363 @@
 [[../parent|See above]] Note: see wikisyntax tests for other parent tests
 [[./sibling|See next]]
 [[...|nothing to see]] [[...]]
+[[//a ] ]]
 [[//docs|See documentation]]
 [[//images/logo.png|Our logo]]
 [[/]]
@@ -376 +377 @@
 <a class="missing wiki" href="/wiki/parent" rel="nofollow">See above?</a> Note: see wikisyntax tests for other parent tests
 <a class="missing wiki" href="/wiki/WikiStart/sibling" rel="nofollow">See next?</a>
 <a class="missing wiki" href="/wiki/..." rel="nofollow">nothing to see?</a> <a class="missing wiki" href="/wiki/..." rel="nofollow">...?</a>
+<a class="missing wiki" href="/wiki/a%20%5D%20" rel="nofollow">a ] ?</a>
 <a href="/docs">See documentation</a>
 <a href="/images/logo.png">Our logo</a>
 <a href="/">/</a>

[Peter Suter]

My (possibly wrong) understanding is:

• _make_lhref_link is only used by _lhref_formatter.
• _lhref_formatter is the internal_handler​ for the lhref​ post-rule.
• But _lhref_formatter is also used as a fallback by _macrolink_formatter (the internal handler for the macrolink post-rule) with _creolelink_re.

• The lhref (long-hand reference?) handling is for [...] links.
  • Here a scheme: (ns) is required. [WikiStart] is not valid and not matched by the lhref post-rule.
• The macrolink fallback / creole link handling is for [[...]] links.
  • Here a scheme: (ns) is optional. [[WikiStart]] is valid and matched by _creolelink_re.

In _make_lhref_link this is ignored. Even the comments there imply [...] (where ns is required) is the only handled scenario.

Now how should [[//a ] ]] be handled? I don't know.

• [[a b ]] links a wiki page a b , similar to [[WikiStart]].
• [[/a b ]] links project-relative server/project/a b , similar to [[/search]].
• [[//a b ]] links server-relative server/a b , similar to [[//demo-1.1]].

But _lhref_relative_target does not match //a ] (or /a ] ) as a possible relative target due to the ], so:

• [[a ] ]] still links a wiki page a ] .
• [[/a ] ]] does not link to project-relative server/project/a ] , but instead again links to the wiki page a ] . Is that useful?
• [[//a ] ]] does not link to server-relative server/a ] . With the proposed fix it would also again link to the wiki page a ] . Is that useful?

Maybe _lhref_relative_target is wrong to reject ]?

But I think the proposed fix is good in the sense that it is an improvement, and somewhat consistent with already existing fallbacks for other strange links.

The next step IMO would be to mention this in the comments. Last it could be investigated if allowing ] in relative links is possible, or maybe first if it is useful.

---

(OT: The documentation on server-relative links are slightly confusing. [/newticket] is not the same as [[//newticket]], e.g. on demo-1.1 [[//newticket]] points to t.e.o.! [/newticket] is the same as [[/newticket]], and [//newticket] is the same as [[//newticket]].)

[Ryan J Ollos]

Replying to psuter:

But I think the proposed fix is good in the sense that it is an improvement, and somewhat consistent with already existing fallbacks for other strange links.

Thanks for the detailed look. For now I'll just push the change that prevents the TypeError. I guess it would be good to sort out the inconsistencies you mentioned, but I can't imagine I'll ever have a need to create a wiki page containing ] or even [...], so I'll wait to see if someone complains before looking further into those issues.

[Ryan J Ollos]

Committed to 1.0-stable in [14772], merged to trunk in [14773].