IndexError: pop from empty list

[stroetgen]

How to Reproduce

While doing a GET operation on /attachment/wiki/xxx/, Trac issued an internal error.

Error accoures when language is other than "English (United States)"

Request parameters:

{'action': u'new',
 'attachfilebutton': u'Datei anh\xe4ngen',
 'path': u'xxx/',
 'realm': u'wiki'}

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0

System Information

Trac	1.0.1
Babel	1.3
Docutils	0.11
Genshi	0.7 (with speedups)
mod_python	3.3.1
Pygments	1.6
pysqlite	2.6.0
Python	2.7.6 (default, Mar 22 2014, 23:03:41) [GCC 4.8.2]
pytz	2012c
setuptools	0.6
SQLite	3.8.2
Subversion	1.8.8 (r1568071)
jQuery	1.7.2

Enabled Plugins

TracExtLinksNewWindow	1.0
TracGanttCalendarPlugin	0.5-r752
TracMasterTickets	2.2
TracTags	0.6
TracTocMacro	11.0.0.3
TracWikiRename	2.1.1
TracWikiToPdfPlugin	2.3.1dev-r0
TracWysiwyg	0.12.0.3

Python Traceback

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/trac/web/main.py", line 497, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.7/dist-packages/trac/web/main.py", line 233, in dispatch
    content_type)
  File "/usr/lib/python2.7/dist-packages/trac/web/chrome.py", line 1015, in render_template
    encoding='utf-8')
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 184, in render
    return encode(generator, method=method, encoding=encoding, out=out)
  File "/usr/lib/python2.7/dist-packages/genshi/output.py", line 58, in encode
    for chunk in iterator:
  File "/usr/lib/python2.7/dist-packages/genshi/output.py", line 350, in __call__
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/output.py", line 829, in __call__
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/output.py", line 669, in __call__
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/output.py", line 774, in __call__
    for kind, data, pos in chain(stream, [(None, None, None)]):
  File "/usr/lib/python2.7/dist-packages/genshi/output.py", line 594, in __call__
    for ev in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 289, in _ensure
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 289, in _ensure
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/trac/web/chrome.py", line 1152, in _strip_accesskeys
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 289, in _ensure
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/trac/web/chrome.py", line 1141, in _generate
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 289, in _ensure
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/template/base.py", line 618, in _include
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/template/markup.py", line 378, in _match
    ctxt, start=idx + 1, **vars):
  File "/usr/lib/python2.7/dist-packages/genshi/template/markup.py", line 378, in _match
    ctxt, start=idx + 1, **vars):
  File "/usr/lib/python2.7/dist-packages/genshi/template/markup.py", line 326, in _match
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/template/base.py", line 558, in _flatten
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 289, in _ensure
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/path.py", line 588, in _generate
    subevent = next()
  File "/usr/lib/python2.7/dist-packages/genshi/template/base.py", line 618, in _include
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/template/markup.py", line 315, in _strip
    event = next()
  File "/usr/lib/python2.7/dist-packages/genshi/template/base.py", line 558, in _flatten
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/core.py", line 289, in _ensure
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/path.py", line 588, in _generate
    subevent = next()
  File "/usr/lib/python2.7/dist-packages/genshi/template/base.py", line 618, in _include
    for event in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/template/markup.py", line 315, in _strip
    event = next()
  File "/usr/lib/python2.7/dist-packages/genshi/template/base.py", line 558, in _flatten
    for kind, data, pos in stream:
  File "/usr/lib/python2.7/dist-packages/genshi/filters/i18n.py", line 178, in _generate
    for event in msgbuf.translate(gettext(msgbuf.format())):
  File "/usr/lib/python2.7/dist-packages/genshi/filters/i18n.py", line 1051, in translate
    events = self.events[order].pop(0)
IndexError: pop from empty list

[Jun Omae]

Why the component is changed to TracWysiwygPlugin? I don't understand your change!

That's a Genshi 0.7 issue. Try to downgrade Genshi 0.6. See ​trac:#11184 and #11242.

[stroetgen]

Sorry, Trac-Error pointed to TracWysiwygPlugin.

Downgrading Genshi to 0.6 solved the problem.