id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
13523	IndexError: pop from empty list	lehnert@…		"==== How to Reproduce ====

While doing a GET operation on `/attachment/ticket/13522/`, Trac issued an internal error.

Trying to add attachments immediately after creating the ticket or also later produces this error (not the first time)

Request parameters:
{{{
{u'action': u'new', 'path': u'13522/', 'realm': u'ticket'}
}}}

User agent: `Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:59.0) Gecko/20100101 Firefox/59.0`

==== System Information ====
''Systeminformation nicht verfügbar''

==== Enabled Plugins ====
''Plugininformation nicht verfügbar''

==== Interface Customization ====
''Interface customization information not available''

==== Python Traceback ====
{{{
Traceback (most recent call last):
  File ""build/bdist.linux-x86_64/egg/trac/web/main.py"", line 623, in _dispatch_request
    dispatcher.dispatch(req)
  File ""build/bdist.linux-x86_64/egg/trac/web/main.py"", line 259, in dispatch
    iterable=chrome.use_chunked_encoding)
  File ""build/bdist.linux-x86_64/egg/trac/web/chrome.py"", line 1165, in render_template
    encoding='utf-8')
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 184, in render
    return encode(generator, method=method, encoding=encoding, out=out)
  File ""/usr/local/lib/python2.7/dist-packages/genshi/output.py"", line 58, in encode
    for chunk in iterator:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/output.py"", line 350, in __call__
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/output.py"", line 829, in __call__
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/output.py"", line 669, in __call__
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/output.py"", line 774, in __call__
    for kind, data, pos in chain(stream, [(None, None, None)]):
  File ""/usr/local/lib/python2.7/dist-packages/genshi/output.py"", line 594, in __call__
    for ev in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""build/bdist.linux-x86_64/egg/trac/web/chrome.py"", line 1432, in _strip_accesskeys
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""build/bdist.linux-x86_64/egg/trac/web/chrome.py"", line 1421, in _generate
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/transform.py"", line 706, in _unmark
    for mark, event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/transform.py"", line 1101, in __call__
    for mark, event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/transform.py"", line 118, in __iter__
    event = self.stream.next()
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/transform.py"", line 734, in __call__
    for mark, event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/transform.py"", line 702, in _mark
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/base.py"", line 618, in _include
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/markup.py"", line 378, in _match
    ctxt, start=idx + 1, **vars):
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/markup.py"", line 378, in _match
    ctxt, start=idx + 1, **vars):
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/markup.py"", line 326, in _match
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/base.py"", line 558, in _flatten
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/path.py"", line 588, in _generate
    subevent = next()
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/base.py"", line 618, in _include
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/markup.py"", line 315, in _strip
    event = next()
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/base.py"", line 558, in _flatten
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/core.py"", line 289, in _ensure
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/path.py"", line 588, in _generate
    subevent = next()
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/base.py"", line 618, in _include
    for event in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/markup.py"", line 315, in _strip
    event = next()
  File ""/usr/local/lib/python2.7/dist-packages/genshi/template/base.py"", line 558, in _flatten
    for kind, data, pos in stream:
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/i18n.py"", line 178, in _generate
    for event in msgbuf.translate(gettext(msgbuf.format())):
  File ""/usr/local/lib/python2.7/dist-packages/genshi/filters/i18n.py"", line 1051, in translate
    events = self.events[order].pop(0)
IndexError: pop from empty list
}}}"	Bugs	closed	To Be Determined	None	Boost 1.63.0	Problem	worksforme