IndexError: pop from empty list

[indianer]

How to Reproduce

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

(please provide additional details here)

Request parameters:

{'action': u'new', 'path': u'WikiStart/', 'realm': u'wiki'}

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0

System Information

Trac	1.0.2
Babel	1.3
Docutils	0.12
Genshi	0.7 (with speedups)
Pygments	2.0.1
pysqlite	2.6.0
Python	2.7.9 (default, Jun 29 2016, 13:08:31) [GCC 4.9.2]
pytz	2012c
setuptools	33.1.1
SQLite	3.8.7.1
jQuery	1.7.2
jQuery UI	1.10.1
jQuery Timepicker	1.2

Enabled Plugins

Python Traceback

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/trac/web/main.py", line 512, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.7/dist-packages/trac/web/main.py", line 240, in dispatch
    content_type)
  File "/usr/lib/python2.7/dist-packages/trac/web/chrome.py", line 1042, 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 1182, 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 1171, in _generate
    for kind, data, pos 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

[Ryan J Ollos]

#11184. See TracFaq#Q:WhydoIseeIndexError:popfromemptylistwhentryingtoaddanattachment

[Ryan J Ollos]

The issue can be resolved by upgrading to ​Genshi 0.7.1.