# pushrebase.py - server-side rebasing of pushed commits # # Copyright 2014 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. import errno, os, tempfile, sys, operator, resource, collections try: import json except ImportError: import simplejson as json from mercurial import bundle2, cmdutil, hg, scmutil, exchange, commands from mercurial import util, error, discovery, changegroup, context, revset from mercurial import obsolete, pushkey, phases, extensions from mercurial import bookmarks, lock as lockmod from mercurial.extensions import wrapcommand, wrapfunction, _order from mercurial.bundlerepo import bundlerepository from mercurial.node import nullid, hex, bin from mercurial.i18n import _ testedwith = '3.4' cmdtable = {} command = cmdutil.command(cmdtable) rebaseparttype = 'b2x:rebase' commonheadsparttype = 'b2x:commonheads' experimental = 'experimental' configonto = 'server-rebase-onto' def uisetup(ui): # remotenames circumvents the default push implementation entirely, so make # sure we load after it so that we wrap it. _order.remove('pushrebase') _order.append('pushrebase') def extsetup(ui): entry = wrapcommand(commands.table, 'push', _push) try: # Don't add the 'to' arg if it already exists extensions.find('remotenames') except KeyError: entry[1].append(('', 'to', '', _('server revision to rebase onto'))) partorder = exchange.b2partsgenorder partorder.insert(partorder.index('changeset'), partorder.pop(partorder.index(rebaseparttype))) partorder.insert(0, partorder.pop(partorder.index(commonheadsparttype))) wrapfunction(discovery, 'checkheads', _checkheads) # we want to disable the heads check because in pushrebase repos, we # expect the heads to change during the push and we should not abort. # The check heads functions are used to verify that the heads haven't # changed since the client did the initial discovery. Pushrebase is meant # to allow concurrent pushes, so the heads may have very well changed. # So let's not do this check. wrapfunction(exchange, 'check_heads', _exchangecheckheads) wrapfunction(exchange, '_pushb2ctxcheckheads', _skipcheckheads) origpushkeyhandler = bundle2.parthandlermapping['pushkey'] newpushkeyhandler = lambda *args, **kwargs: \ bundle2pushkey(origpushkeyhandler, *args, **kwargs) newpushkeyhandler.params = origpushkeyhandler.params bundle2.parthandlermapping['pushkey'] = newpushkeyhandler bundle2.parthandlermapping['b2x:pushkey'] = newpushkeyhandler wrapfunction(exchange, 'unbundle', unbundle) def unbundle(orig, repo, cg, heads, source, url): # Preload the manifests that the client says we'll need. This happens # outside the lock, thus cutting down on our lock time and increasing commit # throughput. if util.safehasattr(cg, 'params'): preloadmfs = cg.params.get('preloadmanifests') if preloadmfs: for mfnode in preloadmfs.split(','): repo.manifest.read(bin(mfnode)) return orig(repo, cg, heads, source, url) def validaterevset(repo, revset): "Abort if this is a rebasable revset, return None otherwise" if not repo.revs(revset): raise util.Abort(_('nothing to rebase')) if repo.revs('%r and public()', revset): raise util.Abort(_('cannot rebase public changesets')) if repo.revs('%r and obsolete()', revset): raise util.Abort(_('cannot rebase obsolete changesets')) heads = repo.revs('heads(%r)', revset) if len(heads) > 1: raise util.Abort(_('cannot rebase divergent changesets')) repo.ui.note(_('validated revset for rebase\n')) def getrebasepart(repo, peer, outgoing, onto, newhead=False): if not outgoing.missing: raise util.Abort(_('no commits to rebase')) if rebaseparttype not in bundle2.bundle2caps(peer): raise util.Abort(_('no server support for %r') % rebaseparttype) validaterevset(repo, revset.formatspec('%ln', outgoing.missing)) cg = changegroup.getlocalchangegroupraw(repo, 'push', outgoing) # .upper() marks this as a mandatory part: server will abort if there's no # handler return bundle2.bundlepart(rebaseparttype.upper(), mandatoryparams={'onto': onto, 'newhead': repr(newhead), }.items(), data = cg) def _checkheads(orig, repo, remote, *args, **kwargs): onto = repo.ui.config(experimental, configonto) if onto: # This is a rebasing push # The rest of the checks are performed during bundle2 part processing; # we need to bypass the regular push checks because it will look like # we're pushing a new head, which isn't normally allowed if not repo.ui.configbool('experimental', 'bundle2-exp', False): raise util.Abort(_('bundle2 needs to be enabled on client')) if not remote.capable('bundle2-exp'): raise util.Abort(_('bundle2 needs to be enabled on server')) return else: return orig(repo, remote, *args, **kwargs) def _exchangecheckheads(orig, repo, *args, **kwargs): onto = repo.ui.config(experimental, configonto) if not onto: # Only do this work if it's not a rebasing push return orig(repo, *args, **kwargs) def _skipcheckheads(orig, pushop, bundler): if not pushop.ui.config(experimental, configonto): # no check if we rebase return orig(pushop, bundler) def _push(orig, ui, repo, *args, **opts): oldonto = ui.backupconfig(experimental, configonto) oldremotenames = ui.backupconfig('remotenames', 'allownonfastforward') oldphasemove = None try: ui.setconfig(experimental, configonto, opts.get('to'), '--to') if ui.config(experimental, configonto): ui.setconfig(experimental, 'bundle2.pushback', True) oldphasemove = wrapfunction(exchange, '_localphasemove', _phasemove) ui.setconfig('remotenames', 'allownonfastforward', True) result = orig(ui, repo, *args, **opts) finally: ui.restoreconfig(oldonto) ui.restoreconfig(oldremotenames) if oldphasemove: exchange._localphasemove = oldphasemove return result def _phasemove(orig, pushop, nodes, phase=phases.public): """prevent commits from being marked public Since these are going to be mutated on the server, they aren't really being published, their successors are. If we mark these as public now, hg evolve will refuse to fix them for us later.""" if phase != phases.public: orig(pushop, nodes, phase) @exchange.b2partsgenerator(commonheadsparttype) def commonheadspartgen(pushop, bundler): bundler.newpart(commonheadsparttype, data=''.join(pushop.outgoing.commonheads)) @bundle2.parthandler(commonheadsparttype) def commonheadshandler(op, inpart): nodeid = inpart.read(20) while len(nodeid) == 20: op.records.add(commonheadsparttype, nodeid) nodeid = inpart.read(20) assert not nodeid # data should split evenly into blocks of 20 bytes @exchange.b2partsgenerator(rebaseparttype) def partgen(pushop, bundler): onto = pushop.ui.config(experimental, configonto) if 'changesets' in pushop.stepsdone or not onto or pushop.force: return pushop.stepsdone.add('changesets') if not pushop.outgoing.missing: # It's important that this text match the text found in upstream # Mercurial, since some tools rely on this string to know if a push # succeeded despite not pushing commits. pushop.ui.status(_('no changes found\n')) pushop.cgresult = 0 return rebasepart = getrebasepart(pushop.repo, pushop.remote, pushop.outgoing, onto, pushop.newbranch) bundler.addpart(rebasepart) # Tell the server which manifests to load before taking the lock. # This helps shorten the duration of the lock, which increases our potential # commit rate. missing = pushop.outgoing.missing roots = pushop.repo.set('parents(%ln) - %ln', missing, missing) preloadnodes = [hex(r.manifestnode()) for r in roots] bundler.addparam("preloadmanifests", ','.join(preloadnodes)) def handlereply(op): # server either succeeds or aborts; no code to read pushop.cgresult = 1 return handlereply bundle2.capabilities[rebaseparttype] = () def _makebundlefile(part): """constructs a temporary bundle file part.data should be an uncompressed v1 changegroup""" fp = None fd, bundlefile = tempfile.mkstemp() try: # guards bundlefile try: # guards fp fp = os.fdopen(fd, 'wb') magic = 'HG10UN' fp.write(magic) data = part.read(resource.getpagesize() - len(magic)) while data: fp.write(data) data = part.read(resource.getpagesize()) finally: fp.close() except: try: os.unlink(bundlefile) except: # we would rather see the original exception pass raise return bundlefile def _getrevs(bundle, onto): 'extracts and validates the revs to be imported' validaterevset(bundle, 'bundle()') revs = [bundle[r] for r in bundle.revs('sort(bundle())')] onto = bundle[onto.hex()] # Fast forward update, no rebase needed if list(bundle.set('bundle() & %d::', onto.rev())): return revs, onto if revs: # We want to rebase the highest bundle root that is an ancestor of # `onto`. oldonto = list(bundle.set('max(parents(bundle()) - bundle() & ::%d)', onto.rev())) if not oldonto: # If there's no shared history, only allow the rebase if the # incoming changes are completely distinct. sharedparents = list(bundle.set('parents(bundle()) - bundle()')) if not sharedparents: return revs, bundle[nullid] raise util.Abort(_('pushed commits do not branch from an ancestor ' 'of the desired destination %s' % onto.hex())) oldonto = oldonto[0] # Computes a list of all files that are in the changegroup, and diffs it # against all the files that changed between the old onto (ex: our old # bookmark location) and the new onto (ex: the server's actual bookmark # location). Since oldonto->onto is the distance of the rebase, this # should catch any conflicting changes. files = reduce(operator.or_, [set(rev.files()) for rev in revs], set()) filematcher = scmutil.matchfiles(bundle, files) commonmanifest = oldonto.manifest().matches(filematcher) ontomanifest = onto.manifest().matches(filematcher) conflicts = ontomanifest.diff(commonmanifest).keys() if conflicts: raise util.Abort(_('conflicting changes in %r') % conflicts) return revs, oldonto def _graft(repo, rev, mapping): '''duplicate changeset "rev" with parents from "mapping"''' oldp1 = rev.p1().node() oldp2 = rev.p2().node() newp1 = mapping.get(oldp1, oldp1) newp2 = mapping.get(oldp2, oldp2) m = rev.manifest() def getfilectx(repo, memctx, path): if path in m: fctx = rev[path] flags = fctx.flags() copied = fctx.renamed() if copied: copied = copied[0] return context.memfilectx(repo, fctx.path(), fctx.data(), islink='l' in flags, isexec='x' in flags, copied=copied) else: return None # If the incoming commit has no parents, but requested a rebase, # allow it only for the first commit. The null/null commit will always # be the first commit since we only allow a nullid->nonnullid mapping if the # incoming commits are a completely distinct history (see `sharedparents` in # getrevs()), so there's no risk of commits with a single null parent # accidentally getting translated first. if oldp1 == nullid and oldp2 == nullid: if newp1 != nullid: newp2 = nullid del mapping[nullid] if oldp1 != nullid and oldp2 != nullid: # If it's a merge commit, Mercurial's rev.files() only returns the files # that are different from both p1 and p2, so it would not capture all of # the incoming changes from p2 (for instance, new files in p2). The fix # is to manually diff the rev manifest and it's p1 to get the list of # files that have changed. We only need to diff against p1, and not p2, # because Mercurial constructs new commits by applying our specified # files on top of a copy of the p1 manifest, so we only need the diff # against p1. files = rev.manifest().diff(repo[oldp1].manifest()).keys() else: files = rev.files() return context.memctx(repo, [newp1, newp2], rev.description(), files, getfilectx, rev.user(), rev.date(), rev.extra(), ).commit() def _buildobsolete(replacements, oldrepo, newrepo): 'adds obsolete markers in replacements if enabled in newrepo' if obsolete.isenabled(newrepo, obsolete.createmarkersopt): markers = [(oldrepo[oldrev], (newrepo[newrev],)) for oldrev, newrev in replacements.items() if newrev != oldrev] obsolete.createmarkers(newrepo, markers) def _addpushbackchangegroup(repo, reply, outgoing): '''adds changegroup part to reply containing revs from outgoing.missing''' cgversions = set(reply.capabilities.get('changegroup')) if not cgversions: cgversions.add('01') version = max(cgversions & set(changegroup.packermap.keys())) cg = changegroup.getlocalchangegroupraw(repo, 'rebase:reply', outgoing, version = version) cgpart = reply.newpart('CHANGEGROUP', data = cg) if version != '01': cgpart.addparam('version', version) def _addpushbackobsolete(repo, reply, newrevs): '''adds obsoletion markers to reply that are relevant to newrevs (if enabled)''' if (obsolete.isenabled(repo, obsolete.exchangeopt) and repo.obsstore): try: markers = repo.obsstore.relevantmarkers(newrevs) exchange.buildobsmarkerspart(reply, markers) except ValueError, exc: repo.ui.status(_("can't send obsolete markers: %s") % exc.message) def _addpushbackparts(op, replacements): '''adds pushback to reply if supported by the client''' if (op.records[commonheadsparttype] and op.reply and 'pushback' in op.reply.capabilities): outgoing = discovery.outgoing(op.repo.changelog, op.records[commonheadsparttype], [new for old, new in replacements.items() if old != new]) if outgoing.missing: _addpushbackchangegroup(op.repo, op.reply, outgoing) _addpushbackobsolete(op.repo, op.reply, replacements.values()) @bundle2.parthandler(rebaseparttype, ('onto', 'newhead')) def bundle2rebase(op, part): '''unbundle a bundle2 containing a changegroup to rebase''' params = part.params tr = op.gettransaction() hookargs = dict(tr.hookargs) bundlefile = None try: onto = scmutil.revsingle(op.repo, params['onto']) except error.RepoLookupError: # Probably a new bookmark. onto == None means don't do rebasing onto = None if not params['newhead']: if not op.repo.revs('%r and head()', params['onto']): raise util.Abort(_('rebase would produce a new head on server')) try: # guards bundlefile bundlefile = _makebundlefile(part) bundle = bundlerepository(op.repo.ui, op.repo.root, bundlefile) # Preload the caches with data we already have. We need to make copies # here so that original repo caches don't get tainted with bundle # specific data. newmancache = bundle.manifest._mancache oldmancache = op.repo.manifest._mancache newmancache._cache = oldmancache._cache.copy() newmancache._order = collections.deque(oldmancache._order) bundle.manifest._cache = op.repo.manifest._cache if onto == None: maxcommonanc = list(bundle.set('max(parents(bundle()) - bundle())')) if not maxcommonanc: onto = op.repo[nullid] else: onto = maxcommonanc[0] revs, oldonto = _getrevs(bundle, onto) op.repo.hook("prechangegroup", **hookargs) mapping = {} # Seed the mapping with oldonto->onto mapping[oldonto.node()] = onto.node() replacements = {} added = [] for rev in revs: newrev = _graft(op.repo, rev, mapping) new = op.repo[newrev] oldnode = rev.node() newnode = new.node() replacements[oldnode] = newnode mapping[oldnode] = newnode added.append(newnode) if 'node' not in tr.hookargs: tr.hookargs['node'] = hex(newnode) hookargs['node'] = hex(newnode) _buildobsolete(replacements, bundle, op.repo) finally: try: if bundlefile: os.unlink(bundlefile) except OSError, e: if e.errno != errno.ENOENT: raise publishing = op.repo.ui.configbool('phases', 'publish', True) if publishing: phases.advanceboundary(op.repo, tr, phases.public, [added[-1]]) p = lambda: tr.writepending() and op.repo.root or "" op.repo.hook("pretxnchangegroup", throw=True, pending=p, **hookargs) def runhooks(): args = hookargs.copy() args['node'] = hex(added[0]) op.repo.hook("changegroup", **args) for n in added: args = hookargs.copy() args['node'] = hex(n) op.repo.hook("incoming", **args) tr.addpostclose('serverrebase-cg-hooks', lambda tr: op.repo._afterlock(runhooks)) _addpushbackparts(op, replacements) for k in replacements.keys(): replacements[hex(k)] = hex(replacements[k]) op.records.add(rebaseparttype, replacements) return 1 def bundle2pushkey(orig, op, part): replacements = dict(sum([record.items() for record in op.records[rebaseparttype]], [])) namespace = pushkey.decode(part.params['namespace']) if namespace == 'phases': key = pushkey.decode(part.params['key']) part.params['key'] = pushkey.encode(replacements.get(key, key)) if namespace == 'bookmarks': new = pushkey.decode(part.params['new']) part.params['new'] = pushkey.encode(replacements.get(new, new)) serverbin = op.repo._bookmarks.get(part.params['key']) clienthex = pushkey.decode(part.params['old']) if serverbin and clienthex: cl = op.repo.changelog revserver = cl.rev(serverbin) revclient = cl.rev(bin(clienthex)) if revclient in cl.ancestors([revserver]): # if the client's bookmark origin is an lagging behind the # server's location for that bookmark (usual for pushrebase) # then update the old location to match the real location # # TODO: We would prefer to only do this for pushrebase pushes # but that isn't straightforward so we just do it always here. # This forbids moving bookmarks backwards from clients. part.params['old'] = pushkey.encode(hex(serverbin)) return orig(op, part)