lock: while releasing, unlink lockfile even if the release function throws Consider a hypothetical bug in the release function that causes it to raise an exception. Also consider the bisect command, which saves its state in a finally clause. Saving the state requires acquiring the wlock. If we don't unlink the lockfile when the exception is thrown, we'll try to acquire the wlock again. We're going to try and acquire a lock again while our old lockfile is on disk. The PID on disk is our own, and of course we're still running, so we won't take over the lock. Hence we'll be stuck waiting for a lock that we left behind ourselves. To avoid this, always unlink the lockfile. This preserves the invariant that self.held > 0 is equivalent to the lockfile existing on disk.

#!/usr/bin/env python
#
# An example FastCGI script for use with flup, edit as necessary

# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = "/path/to/repo/or/config"

# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")

# Uncomment to send python tracebacks to the browser if an error occurs:
#import cgitb; cgitb.enable()

from mercurial import demandimport; demandimport.enable()
from mercurial.hgweb import hgweb
from flup.server.fcgi import WSGIServer
application = hgweb(config)
WSGIServer(application).run()