Mercurial > hg
view hgext/split.py @ 48038:52018f8ef020 stable
persistent-nodemap: introduce a test to highlight possible race
Weakness in the current file caching of the changelog means that a writer can
end up using an outdated docket. This might result in "committed"
persistent-nodemap data from a previous writer to be overwritten by a later
writer. This break the strong "append only" assumption of the persistent nodemap
and can result in confused reader.
The race windows are quite narrow. See the test documentation for details.
The issues is fixed in the next changeset.
Differential Revision: https://phab.mercurial-scm.org/D11481
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Tue, 21 Sep 2021 21:18:50 +0200 |
parents | ca0049946e9a |
children | 5ced12cfa41b |
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# split.py - split a changeset into smaller ones # # Copyright 2015 Laurent Charignon <lcharignon@fb.com> # Copyright 2017 Facebook, Inc. # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """command to split a changeset into smaller ones (EXPERIMENTAL)""" from __future__ import absolute_import from mercurial.i18n import _ from mercurial.node import ( nullrev, short, ) from mercurial import ( bookmarks, cmdutil, commands, error, hg, pycompat, registrar, revsetlang, rewriteutil, scmutil, util, ) # allow people to use split without explicitly enabling rebase extension from . import rebase 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' @command( b'split', [ (b'r', b'rev', b'', _(b"revision to split"), _(b'REV')), (b'', b'rebase', True, _(b'rebase descendants after split')), ] + cmdutil.commitopts2, _(b'hg split [--no-rebase] [[-r] REV]'), helpcategory=command.CATEGORY_CHANGE_MANAGEMENT, helpbasic=True, ) def split(ui, repo, *revs, **opts): """split a changeset into smaller ones Repeatedly prompt changes and commit message for new changesets until there is nothing left in the original changeset. If --rev was not given, split the working directory parent. By default, rebase connected non-obsoleted descendants onto the new changeset. Use --no-rebase to avoid the rebase. """ opts = pycompat.byteskwargs(opts) revlist = [] if opts.get(b'rev'): revlist.append(opts.get(b'rev')) revlist.extend(revs) with repo.wlock(), repo.lock(): tr = repo.transaction(b'split') # If the rebase somehow runs into conflicts, make sure # we close the transaction so the user can continue it. with util.acceptintervention(tr): revs = scmutil.revrange(repo, revlist or [b'.']) if len(revs) > 1: raise error.InputError(_(b'cannot split multiple revisions')) rev = revs.first() # Handle nullrev specially here (instead of leaving for precheck() # below) so we get a nicer message and error code. if rev is None or rev == nullrev: ui.status(_(b'nothing to split\n')) return 1 ctx = repo[rev] if ctx.node() is None: raise error.InputError(_(b'cannot split working directory')) if opts.get(b'rebase'): # Skip obsoleted descendants and their descendants so the rebase # won't cause conflicts for sure. descendants = list(repo.revs(b'(%d::) - (%d)', rev, rev)) torebase = list( repo.revs( b'%ld - (%ld & obsolete())::', descendants, descendants ) ) else: torebase = [] rewriteutil.precheck(repo, [rev] + torebase, b'split') if len(ctx.parents()) > 1: raise error.InputError(_(b'cannot split a merge changeset')) cmdutil.bailifchanged(repo) # Deactivate bookmark temporarily so it won't get moved # unintentionally bname = repo._activebookmark if bname and repo._bookmarks[bname] != ctx.node(): bookmarks.deactivate(repo) wnode = repo[b'.'].node() top = None try: top = dosplit(ui, repo, tr, ctx, opts) finally: # top is None: split failed, need update --clean recovery. # wnode == ctx.node(): wnode split, no need to update. if top is None or wnode != ctx.node(): hg.clean(repo, wnode, show_stats=False) if bname: bookmarks.activate(repo, bname) if torebase and top: dorebase(ui, repo, torebase, top) def dosplit(ui, repo, tr, ctx, opts): committed = [] # [ctx] # Set working parent to ctx.p1(), and keep working copy as ctx's content if ctx.node() != repo.dirstate.p1(): hg.clean(repo, ctx.node(), show_stats=False) with repo.dirstate.parentchange(): scmutil.movedirstate(repo, ctx.p1()) # Any modified, added, removed, deleted result means split is incomplete def incomplete(repo): st = repo.status() return any((st.modified, st.added, st.removed, st.deleted)) # Main split loop while incomplete(repo): if committed: header = _( b'HG: Splitting %s. So far it has been split into:\n' ) % short(ctx.node()) # We don't want color codes in the commit message template, so # disable the label() template function while we render it. with ui.configoverride( {(b'templatealias', b'label(l,x)'): b"x"}, b'split' ): for c in committed: summary = cmdutil.format_changeset_summary(ui, c, b'split') header += _(b'HG: - %s\n') % summary header += _( b'HG: Write commit message for the next split changeset.\n' ) else: header = _( b'HG: Splitting %s. Write commit message for the ' b'first split changeset.\n' ) % short(ctx.node()) opts.update( { b'edit': True, b'interactive': True, b'message': header + ctx.description(), } ) origctx = repo[b'.'] commands.commit(ui, repo, **pycompat.strkwargs(opts)) newctx = repo[b'.'] # Ensure user didn't do a "no-op" split (such as deselecting # everything). if origctx.node() != newctx.node(): committed.append(newctx) if not committed: raise error.InputError(_(b'cannot split an empty revision')) if len(committed) != 1 or committed[0].node() != ctx.node(): # Ensure we don't strip a node if we produce the same commit as already # exists scmutil.cleanupnodes( repo, {ctx.node(): [c.node() for c in committed]}, operation=b'split', fixphase=True, ) return committed[-1] def dorebase(ui, repo, src, destctx): rebase.rebase( ui, repo, rev=[revsetlang.formatspec(b'%ld', src)], dest=revsetlang.formatspec(b'%d', destctx.rev()), )