UnicodeError with its traceback should be logged while rendering genshi template

[Jun Omae]

If an UnicodeError raises while rendering genshi template, traceback of the error will not be logged. The behavior makes increasingly difficult to solve, especially if rendering unknown template location.

I think we should log the error with its traceback in this case.

trac/web/chrome.py

@@ -885 +885 @@
             req.chrome['script_data'] = script_data
             # give some hints when hitting a Genshi unicode error
             if isinstance(e, UnicodeError):
+                self.log.error('Exception caught while rendering %s%s',
+                               filename,
+                               exception_to_unicode(e, traceback=True))
                 pos = self._stream_location(stream)
                 if pos:
                     location = "'%s', line %s, char %s" % pos

[Jun Omae]

That is less-useful….

2015-02-21 18:15:16,332 Trac[chrome] ERROR: Genshi UnicodeDecodeError error while rendering template ticket.html
Traceback (most recent call last):
  File "/src/tracdev/git/trac/web/chrome.py", line 1096, in render_template
    encoding='utf-8')
  File "/venv/py25-1.0/lib/python2.5/site-packages/genshi/core.py", line 184, in render
  ...
  File "/venv/py25-1.0/lib/python2.5/site-packages/genshi/template/eval.py", line 178, in evaluate
  File "/src/tracdev/git/trac/ticket/templates/ticket_box.html", line 124, in <Expression u'wiki_to_html(context, ticket.description, escape_newlines=preserve_newlines)'>
    ${wiki_to_html(context, ticket.description, escape_newlines=preserve_newlines)}
  File "/src/tracdev/git/trac/wiki/formatter.py", line 1579, in format_to_html
    return HtmlFormatter(env, context, wikidom).generate(escape_newlines)
  File "/src/tracdev/git/trac/wiki/formatter.py", line 1534, in generate
    escape_newlines)
  File "/src/tracdev/git/trac/wiki/formatter.py", line 1316, in format
    result = re.sub(self.wikiparser.rules, self.replace, line)
  File "/home/jun66j5/venv/py25-1.0/lib/python2.5/re.py", line 150, in sub
    return _compile(pattern, 0).sub(repl, string, count)
  File "/src/tracdev/git/trac/wiki/formatter.py", line 1236, in replace
    return _markup_to_unicode(replacement)
  File "/src/tracdev/git/trac/wiki/formatter.py", line 109, in _markup_to_unicode
    markup = stream.render('xhtml', encoding=None, strip_whitespace=False)
  File "/venv/py25-1.0/lib/python2.5/site-packages/genshi/core.py", line 184, in render
  File "/venv/py25-1.0/lib/python2.5/site-packages/genshi/output.py", line 57, in encode
  File "/venv/py25-1.0/lib/python2.5/site-packages/genshi/output.py", line 387, in __call__
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 2999: ordinal not in range(128)
2015-02-21 18:15:16,332 Trac[main] WARNING: [192.168.11.13] HTTPInternalError: 500 Trac Error (Genshi UnicodeDecodeError error while rendering template (unknown template location))

Instead, it would be better to add the template filename to error message when (unknown template location).

trac/web/chrome.py

@@ -1107 +1107 @@
                 if pos:
                     location = "'%s', line %s, char %s" % pos
                 else:
-                    location = _("(unknown template location)")
+                    location = '%s %s' % (filename,
+                                          _("(unknown template location)"))
                 raise TracError(_("Genshi %(error)s error while rendering "
                                   "template %(location)s",
                                   error=e.__class__.__name__,

2015-02-21 22:23:56,696 Trac[main] WARNING: [192.168.11.13] HTTPInternalError: 500 Trac Error (Genshi UnicodeDecodeError error while rendering template ticket.html (unknown template location))

[Jun Omae]

Committed the patch in comment:4 in [13779-13780].