[issue2898] too long a path emits a stack trace

[Danek Duvall]

New submission from Danek Duvall <danek.duvall at sun.com>:

A co-worker got the following stack trace when running "hg merge":

** unknown exception encountered, please report by visiting
**  http://mercurial.selenic.com/wiki/BugTracker
** Python 2.6.4 (r264:75706, May 28 2011, 03:27:39) [C]
** Mercurial Distributed SCM (version 1.8.2)
** Extensions loaded:
Traceback (most recent call last):
  File "/bin/hg", line 38, in <module>
    mercurial.dispatch.run()
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 16,
in run
    sys.exit(dispatch(sys.argv[1:]))
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 36,
in dispatch
    return _runcatch(u, args)
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 58,
in _runcatch
    return _dispatch(ui, args)
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 601,
in _dispatch
    cmdpats, cmdoptions)
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 406,
in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 655,
in _runcommand
    return checkargs()
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 609,
in checkargs
    return cmdfunc()
  File "/usr/lib/python2.6/vendor-packages/mercurial/dispatch.py", line 598,
in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **cmdoptions)
  File "/usr/lib/python2.6/vendor-packages/mercurial/util.py", line 433, in
check
    return func(*args, **kwargs)
  File "/usr/lib/python2.6/vendor-packages/mercurial/commands.py", line
2780, in merge
    return hg.merge(repo, node, force=opts.get('force'))
  File "/usr/lib/python2.6/vendor-packages/mercurial/hg.py", line 400, in merge
    stats = mergemod.update(repo, node, True, force, False)
  File "/usr/lib/python2.6/vendor-packages/mercurial/merge.py", line 535, in
update
    wc.status(unknown=True) # prime cache
  File "/usr/lib/python2.6/vendor-packages/mercurial/context.py", line 680,
in status
    stat = self._repo.status(ignored=ignored, clean=clean, unknown=unknown)
  File "/usr/lib/python2.6/vendor-packages/mercurial/localrepo.py", line
1173, in status
    listclean, listunknown)
  File "/usr/lib/python2.6/vendor-packages/mercurial/dirstate.py", line 665,
in status
    listignored).iteritems():
  File "/usr/lib/python2.6/vendor-packages/mercurial/dirstate.py", line 585,
in walk
    entries = listdir(join(nd), stat=True, skip=skip)
ValueError: path too long

When I asked him to modify walk() to print out the path it was choking on,
it turned out to be as I expected -- a path longer than PATH_MAX.  It looks
like some program went wild and created a deep directory hierarchy that it
shouldn't have.  I expect the problem will go away when he removes that
directory.

Still, mercurial shouldn't blow up in this situation.  If it can't actually
do anything beyond PATH_MAX, then something higher up should catch the
error, and exit with a message explaining what the problem is, as well as
mentioning the problematic path.

----------
messages: 16806
nosy: dduvall
priority: bug
status: unread
title: too long a path emits a stack trace

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Mercurial issue tracker <bugs at mercurial.selenic.com>
<http://mercurial.selenic.com/bts/issue2898>
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