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Differential D10504

dirstateguard: use mktemp-like functionality to generate the backup filenames
ClosedPublic

Authored by spectral on Apr 20 2021, 4:08 PM.

Details

Reviewers
Alphare
Group Reviewers
hg-reviewers
Commits
rHG222a42ac5b2d: dirstateguard: use mktemp-like functionality to generate the backup filenames
Summary

Previously these were generated with names like:
dirstate.backup.commit.<memory address of dirstateguard>

This could cause problems if two hg commands ran at the same time that used the
same memory address, (which is apparently not uncommon if chg is involved), as
memory addresses are not unique across processes.

This issue was reported in the post-review comments on
http://phab.mercurial-scm.org/D9952.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

spectral created this revision.Apr 20 2021, 4:08 PM
Alphare added a subscriber: Alphare.Apr 21 2021, 11:54 AM

Thanks for following up, I couldn't trigger it on one pipeline run, which is a good sign (on top of the patch making sense to me).

However, this breaks test-check-code.t and changes the output of test-fncache.t and test-inherit-mode.t.

Alphare requested changes to this revision.Apr 21 2021, 11:54 AM
This revision now requires changes to proceed.Apr 21 2021, 11:54 AM
spectral updated this revision to Diff 27163.Apr 26 2021, 10:01 PM
spectral added a comment.Apr 26 2021, 10:02 PM

I thought I'd run the entire test suite and it passed before sending. Sorry about that! Fixed fncache and inherit-mode by not writing out the narrowspec backup in the mkstemp call. I'm not getting any failures in test-check-code.t, can you share what ones you're seeing?

Alphare accepted this revision.Apr 29 2021, 10:57 AM
In D10504#159779, @spectral wrote:

I thought I'd run the entire test suite and it passed before sending. Sorry about that! Fixed fncache and inherit-mode by not writing out the narrowspec backup in the mkstemp call. I'm not getting any failures in test-check-code.t, can you share what ones you're seeing?

Black was complaining, so I fixed it in flight. This landed on the stable branch, since we've cut a release since then.

This revision is now accepted and ready to land.Apr 29 2021, 10:57 AM
spectral added a commit: rHG222a42ac5b2d: dirstateguard: use mktemp-like functionality to generate the backup filenames.Apr 29 2021, 10:57 AM
This revision was not accepted when it landed; it landed in state Needs Review.
Closed by commit rHG222a42ac5b2d: dirstateguard: use mktemp-like functionality to generate the backup filenames (authored by spectral). · Explain Why
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/dirstateguard.py (29 lines)

Diff 27198

mercurial/dirstateguard.py

# dirstateguard.py - class to allow restoring dirstate after failure # dirstateguard.py - class to allow restoring dirstate after failure
# #
# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com> # Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>
# #
# This software may be used and distributed according to the terms of the # This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version. # GNU General Public License version 2 or any later version.
from __future__ import absolute_import from __future__ import absolute_import
import os
from .i18n import _ from .i18n import _
from . import ( from . import (
error, error,
narrowspec, narrowspec,
requirements,
util, util,
) )
class dirstateguard(util.transactional): class dirstateguard(util.transactional):
"""Restore dirstate at unexpected failure. """Restore dirstate at unexpected failure.
At the construction, this class does: At the construction, this class does:
- write current ``repo.dirstate`` out, and - write current ``repo.dirstate`` out, and
- save ``.hg/dirstate`` into the backup file - save ``.hg/dirstate`` into the backup file
This restores ``.hg/dirstate`` from backup file, if ``release()`` This restores ``.hg/dirstate`` from backup file, if ``release()``
is invoked before ``close()``. is invoked before ``close()``.
This just removes the backup file at ``close()`` before ``release()``. This just removes the backup file at ``close()`` before ``release()``.
""" """
def __init__(self, repo, name): def __init__(self, repo, name):
self._repo = repo self._repo = repo
self._active = False self._active = False
self._closed = False self._closed = False
self._backupname = b'dirstate.backup.%s.%d' % (name, id(self))
self._narrowspecbackupname = b'narrowspec.backup.%s.%d' % ( def getname(prefix):
name, fd, fname = repo.vfs.mkstemp(prefix=prefix)
id(self), os.close(fd)
) return fname
self._backupname = getname(b'dirstate.backup.%s.' % name)
repo.dirstate.savebackup(repo.currenttransaction(), self._backupname) repo.dirstate.savebackup(repo.currenttransaction(), self._backupname)
# Don't make this the empty string, things may join it with stuff and
# blindly try to unlink it, which could be bad.
self._narrowspecbackupname = None
if requirements.NARROW_REQUIREMENT in repo.requirements:
self._narrowspecbackupname = getname(
b'narrowspec.backup.%s.' % name
)
narrowspec.savewcbackup(repo, self._narrowspecbackupname) narrowspec.savewcbackup(repo, self._narrowspecbackupname)
self._active = True self._active = True
def __del__(self): def __del__(self):
if self._active: # still active if self._active: # still active
# this may occur, even if this class is used correctly: # this may occur, even if this class is used correctly:
# for example, releasing other resources like transaction # for example, releasing other resources like transaction
# may raise exception before ``dirstateguard.release`` in # may raise exception before ``dirstateguard.release`` in
# ``release(tr, ....)``. # ``release(tr, ....)``.
self._abort() self._abort()
def close(self): def close(self):
if not self._active: # already inactivated if not self._active: # already inactivated
msg = ( msg = (
_(b"can't close already inactivated backup: %s") _(b"can't close already inactivated backup: %s")
% self._backupname % self._backupname
) )
raise error.Abort(msg) raise error.Abort(msg)
self._repo.dirstate.clearbackup( self._repo.dirstate.clearbackup(
self._repo.currenttransaction(), self._backupname self._repo.currenttransaction(), self._backupname
) )
if self._narrowspecbackupname:
narrowspec.clearwcbackup(self._repo, self._narrowspecbackupname) narrowspec.clearwcbackup(self._repo, self._narrowspecbackupname)
self._active = False self._active = False
self._closed = True self._closed = True
def _abort(self): def _abort(self):
if self._narrowspecbackupname:
narrowspec.restorewcbackup(self._repo, self._narrowspecbackupname) narrowspec.restorewcbackup(self._repo, self._narrowspecbackupname)
self._repo.dirstate.restorebackup( self._repo.dirstate.restorebackup(
self._repo.currenttransaction(), self._backupname self._repo.currenttransaction(), self._backupname
) )
self._active = False self._active = False
def release(self): def release(self):
if not self._closed: if not self._closed:
if not self._active: # already inactivated if not self._active: # already inactivated
msg = ( msg = (
_(b"can't release already inactivated backup: %s") _(b"can't release already inactivated backup: %s")
% self._backupname % self._backupname
) )
raise error.Abort(msg) raise error.Abort(msg)
self._abort() self._abort()