view contrib/dirstatenonnormalcheck.py @ 27917:97e0dc6d248c stable

repoview: fix corrupted hiddencache crash Mercurial (issue5042)

Before this patch if the hiddencache existed but was empty, it would crash
mercurial. This patch adds exception handling when reading the hiddencache to
avoid the issue.
When encountering a corrupted cache file we print a devel warning. There would
be no point in issuing a normal warning as the user wouldn't be able to do
anything about the situation.

The warning looks like:

devel-warn: corrupted hidden cache, removing it at: /path/to/repoview.py

# dirstatenonnormalcheck.py - extension to check the consistency of the
# dirstate's non-normal map
#
# For most operations on dirstate, this extensions checks that the nonnormalset
# contains the right entries.
# It compares the nonnormal file to a nonnormalset built from the map of all
# the files in the dirstate to check that they contain the same files.

from __future__ import absolute_import

from mercurial import (
    dirstate,
    extensions,
)

def nonnormalentries(dmap):
    """Compute nonnormal entries from dirstate's dmap"""
    res = set()
    for f, e in dmap.iteritems():
        if e[0] != 'n' or e[3] == -1:
            res.add(f)
    return res

def checkconsistency(ui, orig, dmap, _nonnormalset, label):
    """Compute nonnormalset from dmap, check that it matches _nonnormalset"""
    nonnormalcomputedmap = nonnormalentries(dmap)
    if _nonnormalset != nonnormalcomputedmap:
        ui.develwarn("%s call to %s\n" % (label, orig))
        ui.develwarn("inconsistency in nonnormalset\n")
        ui.develwarn("[nonnormalset] %s\n" % _nonnormalset)
        ui.develwarn("[map] %s\n" % nonnormalcomputedmap)

def _checkdirstate(orig, self, arg):
    """Check nonnormal set consistency before and after the call to orig"""
    checkconsistency(self._ui, orig, self._map, self._nonnormalset, "before")
    r = orig(self, arg)
    checkconsistency(self._ui, orig, self._map, self._nonnormalset, "after")
    return r

def extsetup(ui):
    """Wrap functions modifying dirstate to check nonnormalset consistency"""
    dirstatecl = dirstate.dirstate
    devel = ui.configbool('devel', 'all-warnings')
    paranoid = ui.configbool('experimental', 'nonnormalparanoidcheck')
    if devel:
        extensions.wrapfunction(dirstatecl, '_writedirstate', _checkdirstate)
        if paranoid:
            # We don't do all these checks when paranoid is disable as it would
            # make the extension run very slowly on large repos
            extensions.wrapfunction(dirstatecl, 'normallookup', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'otherparent', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'normal', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'write', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'add', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'remove', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'merge', _checkdirstate)
            extensions.wrapfunction(dirstatecl, 'drop', _checkdirstate)