contrib/lock-checker.py

lock-checker: new contrib extension based on work done by Mads

This makes it possible to do lock validation as part of a normal test
run. I didn't attempt any wlock validation because that's a bit more
subtle to detect properly. Thanks to the initial patch from Mads for
the idea.

"""Extension to verify locks are obtained in the required places.

This works by wrapping functions that should be surrounded by a lock
and asserting the lock is held. Missing locks are called out with a
traceback printed to stderr.

This currently only checks store locks, not working copy locks.
"""
import os
import traceback

def _warnstack(ui, msg, skip=1):
    '''issue warning with the message and the current stack, skipping the
    skip last entries'''
    ui.warn('%s at:\n' % msg)
    entries = traceback.extract_stack()[:-skip]
    fnmax = max(len(entry[0]) for entry in entries)
    for fn, ln, func, _text in entries:
        ui.warn(' %*s:%-4s in %s\n' % (fnmax, fn, ln, func))

def _checklock(repo):
    l = repo._lockref and repo._lockref()
    if l is None or not l.held:
        _warnstack(repo.ui, 'missing lock', skip=2)

def reposetup(ui, repo):
    orig = repo.__class__
    class lockcheckrepo(repo.__class__):
        def _writejournal(self, *args, **kwargs):
            _checklock(self)
            return orig._writejournal(self, *args, **kwargs)

        def transaction(self, *args, **kwargs):
            _checklock(self)
            return orig.transaction(self, *args, **kwargs)

        # TODO(durin42): kiilerix had a commented-out lock check in
        # writebranchcache and _writerequirements

        def _tag(self, *args, **kwargs):
            _checklock(self)
            return orig._tag(self, *args, **kwargs)

        def write(self, *args, **kwargs):
            assert os.path.lexists(self._join('.hg/wlock'))
            return orig.write(self, *args, **kwargs)

    repo.__class__ = lockcheckrepo