Mercurial > hg
view hgext/schemes.py @ 47799:3fffb48539ee stable
rust-nodemap: falling back to C impl as mitigation
This is a mitigation for https://bz.mercurial-scm.org/show_bug.cgi?id=6554
We see sometimes almost all data except the most recent revisions
removed from the persistent nodemap, but we don't know how to
reproduce yet.
This has sadly repercussions beyond just needing to reconstruct the
persistent nodemap: for instance, this automatically filters out
all bookmarks pointing to revisions that the nodemap cannot resolve.
If such filtering happens in a transaction, the update of the
bookmarks file that happens at the end of transaction loses all
bookmarks that have been affected. There may be similar consequences
for other data.
So this is a data loss, something that we have to prevent as soon as
possible.
As a mitigation measure, we will now fallback to the C implementation
in case nodemap lookups failed. This will add some latency, e.g., in
discovery, yet less than disabling the persistent nodemap entirely.
We considered implementing the fallback directly on the Python
side, but `revlog.get_rev()` is not systematically used, there are
also several direct calls to the index method (`self.index.rev()` for
a `revlog` instance). It is therefore more direct to implement the
mitigation in the rust-cpython wrapper.
Differential Revision: https://phab.mercurial-scm.org/D11238
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Sun, 01 Aug 2021 14:39:38 +0200 |
parents | ffd3e823a7e5 |
children | 6000f5b25c9b |
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# Copyright 2009, Alexander Solovyov <piranha@piranha.org.ua> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """extend schemes with shortcuts to repository swarms This extension allows you to specify shortcuts for parent URLs with a lot of repositories to act like a scheme, for example:: [schemes] py = http://code.python.org/hg/ After that you can use it like:: hg clone py://trunk/ Additionally there is support for some more complex schemas, for example used by Google Code:: [schemes] gcode = http://{1}.googlecode.com/hg/ The syntax is taken from Mercurial templates, and you have unlimited number of variables, starting with ``{1}`` and continuing with ``{2}``, ``{3}`` and so on. This variables will receive parts of URL supplied, split by ``/``. Anything not specified as ``{part}`` will be just appended to an URL. For convenience, the extension adds these schemes by default:: [schemes] py = http://hg.python.org/ bb = https://bitbucket.org/ bb+ssh = ssh://hg@bitbucket.org/ gcode = https://{1}.googlecode.com/hg/ kiln = https://{1}.kilnhg.com/Repo/ You can override a predefined scheme by defining a new scheme with the same name. """ from __future__ import absolute_import import os import re from mercurial.i18n import _ from mercurial import ( error, extensions, hg, pycompat, registrar, templater, ) from mercurial.utils import ( urlutil, ) cmdtable = {} command = registrar.command(cmdtable) # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should # be specifying the version(s) of Mercurial they are tested with, or # leave the attribute unspecified. testedwith = b'ships-with-hg-core' _partre = re.compile(br'{(\d+)\}') class ShortRepository(object): def __init__(self, url, scheme, templater): self.scheme = scheme self.templater = templater self.url = url try: self.parts = max(map(int, _partre.findall(self.url))) except ValueError: self.parts = 0 def __repr__(self): return b'<ShortRepository: %s>' % self.scheme def instance(self, ui, url, create, intents=None, createopts=None): url = self.resolve(url) return hg._peerlookup(url).instance( ui, url, create, intents=intents, createopts=createopts ) def resolve(self, url): # Should this use the urlutil.url class, or is manual parsing better? try: url = url.split(b'://', 1)[1] except IndexError: raise error.Abort(_(b"no '://' in scheme url '%s'") % url) parts = url.split(b'/', self.parts) if len(parts) > self.parts: tail = parts[-1] parts = parts[:-1] else: tail = b'' context = {b'%d' % (i + 1): v for i, v in enumerate(parts)} return b''.join(self.templater.process(self.url, context)) + tail def hasdriveletter(orig, path): if path: for scheme in schemes: if path.startswith(scheme + b':'): return False return orig(path) schemes = { b'py': b'http://hg.python.org/', b'bb': b'https://bitbucket.org/', b'bb+ssh': b'ssh://hg@bitbucket.org/', b'gcode': b'https://{1}.googlecode.com/hg/', b'kiln': b'https://{1}.kilnhg.com/Repo/', } def extsetup(ui): schemes.update(dict(ui.configitems(b'schemes'))) t = templater.engine(templater.parse) for scheme, url in schemes.items(): if ( pycompat.iswindows and len(scheme) == 1 and scheme.isalpha() and os.path.exists(b'%s:\\' % scheme) ): raise error.Abort( _( b'custom scheme %s:// conflicts with drive ' b'letter %s:\\\n' ) % (scheme, scheme.upper()) ) hg.schemes[scheme] = ShortRepository(url, scheme, t) extensions.wrapfunction(urlutil, b'hasdriveletter', hasdriveletter) @command(b'debugexpandscheme', norepo=True) def expandscheme(ui, url, **opts): """given a repo path, provide the scheme-expanded path""" repo = hg._peerlookup(url) if isinstance(repo, ShortRepository): url = repo.resolve(url) ui.write(url + b'\n')