Mercurial > hg
view mercurial/repair.py @ 45059:79f6f9fa18c1
documentation: add some internals documentation about bid merge
This is an important algorithm that was only documented on the wiki so far.
Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.
Differential Revision: https://phab.mercurial-scm.org/D8711
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Mon, 22 Jun 2020 13:32:20 +0200 |
parents | 9d2b2df2c2ba |
children | c93dd9d9f1e6 |
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# repair.py - functions for repository repair for mercurial # # Copyright 2005, 2006 Chris Mason <mason@suse.com> # Copyright 2007 Matt Mackall # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import errno from .i18n import _ from .node import ( hex, short, ) from . import ( bundle2, changegroup, discovery, error, exchange, obsolete, obsutil, pathutil, phases, pycompat, util, ) from .utils import ( hashutil, stringutil, ) def backupbundle( repo, bases, heads, node, suffix, compress=True, obsolescence=True ): """create a bundle with the specified revisions as a backup""" backupdir = b"strip-backup" vfs = repo.vfs if not vfs.isdir(backupdir): vfs.mkdir(backupdir) # Include a hash of all the nodes in the filename for uniqueness allcommits = repo.set(b'%ln::%ln', bases, heads) allhashes = sorted(c.hex() for c in allcommits) totalhash = hashutil.sha1(b''.join(allhashes)).digest() name = b"%s/%s-%s-%s.hg" % ( backupdir, short(node), hex(totalhash[:4]), suffix, ) cgversion = changegroup.localversion(repo) comp = None if cgversion != b'01': bundletype = b"HG20" if compress: comp = b'BZ' elif compress: bundletype = b"HG10BZ" else: bundletype = b"HG10UN" outgoing = discovery.outgoing(repo, missingroots=bases, missingheads=heads) contentopts = { b'cg.version': cgversion, b'obsolescence': obsolescence, b'phases': True, } return bundle2.writenewbundle( repo.ui, repo, b'strip', name, bundletype, outgoing, contentopts, vfs, compression=comp, ) def _collectfiles(repo, striprev): """find out the filelogs affected by the strip""" files = set() for x in pycompat.xrange(striprev, len(repo)): files.update(repo[x].files()) return sorted(files) def _collectrevlog(revlog, striprev): _, brokenset = revlog.getstrippoint(striprev) return [revlog.linkrev(r) for r in brokenset] def _collectbrokencsets(repo, files, striprev): """return the changesets which will be broken by the truncation""" s = set() for revlog in manifestrevlogs(repo): s.update(_collectrevlog(revlog, striprev)) for fname in files: s.update(_collectrevlog(repo.file(fname), striprev)) return s def strip(ui, repo, nodelist, backup=True, topic=b'backup'): # This function requires the caller to lock the repo, but it operates # within a transaction of its own, and thus requires there to be no current # transaction when it is called. if repo.currenttransaction() is not None: raise error.ProgrammingError(b'cannot strip from inside a transaction') # Simple way to maintain backwards compatibility for this # argument. if backup in [b'none', b'strip']: backup = False repo = repo.unfiltered() repo.destroying() vfs = repo.vfs # load bookmark before changelog to avoid side effect from outdated # changelog (see repo._refreshchangelog) repo._bookmarks cl = repo.changelog # TODO handle undo of merge sets if isinstance(nodelist, bytes): nodelist = [nodelist] striplist = [cl.rev(node) for node in nodelist] striprev = min(striplist) files = _collectfiles(repo, striprev) saverevs = _collectbrokencsets(repo, files, striprev) # Some revisions with rev > striprev may not be descendants of striprev. # We have to find these revisions and put them in a bundle, so that # we can restore them after the truncations. # To create the bundle we use repo.changegroupsubset which requires # the list of heads and bases of the set of interesting revisions. # (head = revision in the set that has no descendant in the set; # base = revision in the set that has no ancestor in the set) tostrip = set(striplist) saveheads = set(saverevs) for r in cl.revs(start=striprev + 1): if any(p in tostrip for p in cl.parentrevs(r)): tostrip.add(r) if r not in tostrip: saverevs.add(r) saveheads.difference_update(cl.parentrevs(r)) saveheads.add(r) saveheads = [cl.node(r) for r in saveheads] # compute base nodes if saverevs: descendants = set(cl.descendants(saverevs)) saverevs.difference_update(descendants) savebases = [cl.node(r) for r in saverevs] stripbases = [cl.node(r) for r in tostrip] stripobsidx = obsmarkers = () if repo.ui.configbool(b'devel', b'strip-obsmarkers'): obsmarkers = obsutil.exclusivemarkers(repo, stripbases) if obsmarkers: stripobsidx = [ i for i, m in enumerate(repo.obsstore) if m in obsmarkers ] newbmtarget, updatebm = _bookmarkmovements(repo, tostrip) backupfile = None node = nodelist[-1] if backup: backupfile = _createstripbackup(repo, stripbases, node, topic) # create a changegroup for all the branches we need to keep tmpbundlefile = None if saveheads: # do not compress temporary bundle if we remove it from disk later # # We do not include obsolescence, it might re-introduce prune markers # we are trying to strip. This is harmless since the stripped markers # are already backed up and we did not touched the markers for the # saved changesets. tmpbundlefile = backupbundle( repo, savebases, saveheads, node, b'temp', compress=False, obsolescence=False, ) with ui.uninterruptible(): try: with repo.transaction(b"strip") as tr: # TODO this code violates the interface abstraction of the # transaction and makes assumptions that file storage is # using append-only files. We'll need some kind of storage # API to handle stripping for us. offset = len(tr._entries) tr.startgroup() cl.strip(striprev, tr) stripmanifest(repo, striprev, tr, files) for fn in files: repo.file(fn).strip(striprev, tr) tr.endgroup() for i in pycompat.xrange(offset, len(tr._entries)): file, troffset, ignore = tr._entries[i] with repo.svfs(file, b'a', checkambig=True) as fp: fp.truncate(troffset) if troffset == 0: repo.store.markremoved(file) deleteobsmarkers(repo.obsstore, stripobsidx) del repo.obsstore repo.invalidatevolatilesets() repo._phasecache.filterunknown(repo) if tmpbundlefile: ui.note(_(b"adding branch\n")) f = vfs.open(tmpbundlefile, b"rb") gen = exchange.readbundle(ui, f, tmpbundlefile, vfs) if not repo.ui.verbose: # silence internal shuffling chatter repo.ui.pushbuffer() tmpbundleurl = b'bundle:' + vfs.join(tmpbundlefile) txnname = b'strip' if not isinstance(gen, bundle2.unbundle20): txnname = b"strip\n%s" % util.hidepassword(tmpbundleurl) with repo.transaction(txnname) as tr: bundle2.applybundle( repo, gen, tr, source=b'strip', url=tmpbundleurl ) if not repo.ui.verbose: repo.ui.popbuffer() f.close() with repo.transaction(b'repair') as tr: bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm] repo._bookmarks.applychanges(repo, tr, bmchanges) # remove undo files for undovfs, undofile in repo.undofiles(): try: undovfs.unlink(undofile) except OSError as e: if e.errno != errno.ENOENT: ui.warn( _(b'error removing %s: %s\n') % ( undovfs.join(undofile), stringutil.forcebytestr(e), ) ) except: # re-raises if backupfile: ui.warn( _(b"strip failed, backup bundle stored in '%s'\n") % vfs.join(backupfile) ) if tmpbundlefile: ui.warn( _(b"strip failed, unrecovered changes stored in '%s'\n") % vfs.join(tmpbundlefile) ) ui.warn( _( b"(fix the problem, then recover the changesets with " b"\"hg unbundle '%s'\")\n" ) % vfs.join(tmpbundlefile) ) raise else: if tmpbundlefile: # Remove temporary bundle only if there were no exceptions vfs.unlink(tmpbundlefile) repo.destroyed() # return the backup file path (or None if 'backup' was False) so # extensions can use it return backupfile def softstrip(ui, repo, nodelist, backup=True, topic=b'backup'): """perform a "soft" strip using the archived phase""" tostrip = [c.node() for c in repo.set(b'sort(%ln::)', nodelist)] if not tostrip: return None newbmtarget, updatebm = _bookmarkmovements(repo, tostrip) if backup: node = tostrip[0] backupfile = _createstripbackup(repo, tostrip, node, topic) with repo.transaction(b'strip') as tr: phases.retractboundary(repo, tr, phases.archived, tostrip) bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm] repo._bookmarks.applychanges(repo, tr, bmchanges) return backupfile def _bookmarkmovements(repo, tostrip): # compute necessary bookmark movement bm = repo._bookmarks updatebm = [] for m in bm: rev = repo[bm[m]].rev() if rev in tostrip: updatebm.append(m) newbmtarget = None # If we need to move bookmarks, compute bookmark # targets. Otherwise we can skip doing this logic. if updatebm: # For a set s, max(parents(s) - s) is the same as max(heads(::s - s)), # but is much faster newbmtarget = repo.revs(b'max(parents(%ld) - (%ld))', tostrip, tostrip) if newbmtarget: newbmtarget = repo[newbmtarget.first()].node() else: newbmtarget = b'.' return newbmtarget, updatebm def _createstripbackup(repo, stripbases, node, topic): # backup the changeset we are about to strip vfs = repo.vfs cl = repo.changelog backupfile = backupbundle(repo, stripbases, cl.heads(), node, topic) repo.ui.status(_(b"saved backup bundle to %s\n") % vfs.join(backupfile)) repo.ui.log( b"backupbundle", b"saved backup bundle to %s\n", vfs.join(backupfile) ) return backupfile def safestriproots(ui, repo, nodes): """return list of roots of nodes where descendants are covered by nodes""" torev = repo.unfiltered().changelog.rev revs = {torev(n) for n in nodes} # tostrip = wanted - unsafe = wanted - ancestors(orphaned) # orphaned = affected - wanted # affected = descendants(roots(wanted)) # wanted = revs revset = b'%ld - ( ::( (roots(%ld):: and not _phase(%s)) -%ld) )' tostrip = set(repo.revs(revset, revs, revs, phases.internal, revs)) notstrip = revs - tostrip if notstrip: nodestr = b', '.join(sorted(short(repo[n].node()) for n in notstrip)) ui.warn( _(b'warning: orphaned descendants detected, not stripping %s\n') % nodestr ) return [c.node() for c in repo.set(b'roots(%ld)', tostrip)] class stripcallback(object): """used as a transaction postclose callback""" def __init__(self, ui, repo, backup, topic): self.ui = ui self.repo = repo self.backup = backup self.topic = topic or b'backup' self.nodelist = [] def addnodes(self, nodes): self.nodelist.extend(nodes) def __call__(self, tr): roots = safestriproots(self.ui, self.repo, self.nodelist) if roots: strip(self.ui, self.repo, roots, self.backup, self.topic) def delayedstrip(ui, repo, nodelist, topic=None, backup=True): """like strip, but works inside transaction and won't strip irreverent revs nodelist must explicitly contain all descendants. Otherwise a warning will be printed that some nodes are not stripped. Will do a backup if `backup` is True. The last non-None "topic" will be used as the backup topic name. The default backup topic name is "backup". """ tr = repo.currenttransaction() if not tr: nodes = safestriproots(ui, repo, nodelist) return strip(ui, repo, nodes, backup=backup, topic=topic) # transaction postclose callbacks are called in alphabet order. # use '\xff' as prefix so we are likely to be called last. callback = tr.getpostclose(b'\xffstrip') if callback is None: callback = stripcallback(ui, repo, backup=backup, topic=topic) tr.addpostclose(b'\xffstrip', callback) if topic: callback.topic = topic callback.addnodes(nodelist) def stripmanifest(repo, striprev, tr, files): for revlog in manifestrevlogs(repo): revlog.strip(striprev, tr) def manifestrevlogs(repo): yield repo.manifestlog.getstorage(b'') if b'treemanifest' in repo.requirements: # This logic is safe if treemanifest isn't enabled, but also # pointless, so we skip it if treemanifest isn't enabled. for unencoded, encoded, size in repo.store.datafiles(): if unencoded.startswith(b'meta/') and unencoded.endswith( b'00manifest.i' ): dir = unencoded[5:-12] yield repo.manifestlog.getstorage(dir) def rebuildfncache(ui, repo): """Rebuilds the fncache file from repo history. Missing entries will be added. Extra entries will be removed. """ repo = repo.unfiltered() if b'fncache' not in repo.requirements: ui.warn( _( b'(not rebuilding fncache because repository does not ' b'support fncache)\n' ) ) return with repo.lock(): fnc = repo.store.fncache fnc.ensureloaded(warn=ui.warn) oldentries = set(fnc.entries) newentries = set() seenfiles = set() progress = ui.makeprogress( _(b'rebuilding'), unit=_(b'changesets'), total=len(repo) ) for rev in repo: progress.update(rev) ctx = repo[rev] for f in ctx.files(): # This is to minimize I/O. if f in seenfiles: continue seenfiles.add(f) i = b'data/%s.i' % f d = b'data/%s.d' % f if repo.store._exists(i): newentries.add(i) if repo.store._exists(d): newentries.add(d) progress.complete() if b'treemanifest' in repo.requirements: # This logic is safe if treemanifest isn't enabled, but also # pointless, so we skip it if treemanifest isn't enabled. for dir in pathutil.dirs(seenfiles): i = b'meta/%s/00manifest.i' % dir d = b'meta/%s/00manifest.d' % dir if repo.store._exists(i): newentries.add(i) if repo.store._exists(d): newentries.add(d) addcount = len(newentries - oldentries) removecount = len(oldentries - newentries) for p in sorted(oldentries - newentries): ui.write(_(b'removing %s\n') % p) for p in sorted(newentries - oldentries): ui.write(_(b'adding %s\n') % p) if addcount or removecount: ui.write( _(b'%d items added, %d removed from fncache\n') % (addcount, removecount) ) fnc.entries = newentries fnc._dirty = True with repo.transaction(b'fncache') as tr: fnc.write(tr) else: ui.write(_(b'fncache already up to date\n')) def deleteobsmarkers(obsstore, indices): """Delete some obsmarkers from obsstore and return how many were deleted 'indices' is a list of ints which are the indices of the markers to be deleted. Every invocation of this function completely rewrites the obsstore file, skipping the markers we want to be removed. The new temporary file is created, remaining markers are written there and on .close() this file gets atomically renamed to obsstore, thus guaranteeing consistency.""" if not indices: # we don't want to rewrite the obsstore with the same content return left = [] current = obsstore._all n = 0 for i, m in enumerate(current): if i in indices: n += 1 continue left.append(m) newobsstorefile = obsstore.svfs(b'obsstore', b'w', atomictemp=True) for bytes in obsolete.encodemarkers(left, True, obsstore._version): newobsstorefile.write(bytes) newobsstorefile.close() return n