Mercurial > hg
view mercurial/phases.py @ 33822:42ad7cc645a4
copies: add more details to the documentation of mergecopies()
This documentation is very helpful for any developer to understand what
copytracing is and what the function does. Since this is the main function of
doing copytracing, I have also included bits about copytracing in it.
This additions are picked from a doc by Stash@Fb. So thanks to him.
Differential Revision: https://phab.mercurial-scm.org/D409
author | Pulkit Goyal <7895pulkit@gmail.com> |
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date | Wed, 16 Aug 2017 00:25:20 +0530 |
parents | 57a017f79e96 |
children | 5779d096a696 |
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""" Mercurial phases support code --- Copyright 2011 Pierre-Yves David <pierre-yves.david@ens-lyon.org> Logilab SA <contact@logilab.fr> Augie Fackler <durin42@gmail.com> This software may be used and distributed according to the terms of the GNU General Public License version 2 or any later version. --- This module implements most phase logic in mercurial. Basic Concept ============= A 'changeset phase' is an indicator that tells us how a changeset is manipulated and communicated. The details of each phase is described below, here we describe the properties they have in common. Like bookmarks, phases are not stored in history and thus are not permanent and leave no audit trail. First, no changeset can be in two phases at once. Phases are ordered, so they can be considered from lowest to highest. The default, lowest phase is 'public' - this is the normal phase of existing changesets. A child changeset can not be in a lower phase than its parents. These phases share a hierarchy of traits: immutable shared public: X X draft: X secret: Local commits are draft by default. Phase Movement and Exchange =========================== Phase data is exchanged by pushkey on pull and push. Some servers have a publish option set, we call such a server a "publishing server". Pushing a draft changeset to a publishing server changes the phase to public. A small list of fact/rules define the exchange of phase: * old client never changes server states * pull never changes server states * publish and old server changesets are seen as public by client * any secret changeset seen in another repository is lowered to at least draft Here is the final table summing up the 49 possible use cases of phase exchange: server old publish non-publish N X N D P N D P old client pull N - X/X - X/D X/P - X/D X/P X - X/X - X/D X/P - X/D X/P push X X/X X/X X/P X/P X/P X/D X/D X/P new client pull N - P/X - P/D P/P - D/D P/P D - P/X - P/D P/P - D/D P/P P - P/X - P/D P/P - P/D P/P push D P/X P/X P/P P/P P/P D/D D/D P/P P P/X P/X P/P P/P P/P P/P P/P P/P Legend: A/B = final state on client / state on server * N = new/not present, * P = public, * D = draft, * X = not tracked (i.e., the old client or server has no internal way of recording the phase.) passive = only pushes A cell here can be read like this: "When a new client pushes a draft changeset (D) to a publishing server where it's not present (N), it's marked public on both sides (P/P)." Note: old client behave as a publishing server with draft only content - other people see it as public - content is pushed as draft """ from __future__ import absolute_import import errno from .i18n import _ from .node import ( bin, hex, nullid, nullrev, short, ) from . import ( error, smartset, txnutil, util, ) allphases = public, draft, secret = range(3) trackedphases = allphases[1:] phasenames = ['public', 'draft', 'secret'] def _readroots(repo, phasedefaults=None): """Read phase roots from disk phasedefaults is a list of fn(repo, roots) callable, which are executed if the phase roots file does not exist. When phases are being initialized on an existing repository, this could be used to set selected changesets phase to something else than public. Return (roots, dirty) where dirty is true if roots differ from what is being stored. """ repo = repo.unfiltered() dirty = False roots = [set() for i in allphases] try: f, pending = txnutil.trypending(repo.root, repo.svfs, 'phaseroots') try: for line in f: phase, nh = line.split() roots[int(phase)].add(bin(nh)) finally: f.close() except IOError as inst: if inst.errno != errno.ENOENT: raise if phasedefaults: for f in phasedefaults: roots = f(repo, roots) dirty = True return roots, dirty def _trackphasechange(data, rev, old, new): """add a phase move the <data> dictionnary If data is None, nothing happens. """ if data is None: return existing = data.get(rev) if existing is not None: old = existing[0] data[rev] = (old, new) class phasecache(object): def __init__(self, repo, phasedefaults, _load=True): if _load: # Cheap trick to allow shallow-copy without copy module self.phaseroots, self.dirty = _readroots(repo, phasedefaults) self._phaserevs = None self._phasesets = None self.filterunknown(repo) self.opener = repo.svfs def getrevset(self, repo, phases): """return a smartset for the given phases""" self.loadphaserevs(repo) # ensure phase's sets are loaded if self._phasesets and all(self._phasesets[p] is not None for p in phases): # fast path - use _phasesets revs = self._phasesets[phases[0]] if len(phases) > 1: revs = revs.copy() # only copy when needed for p in phases[1:]: revs.update(self._phasesets[p]) if repo.changelog.filteredrevs: revs = revs - repo.changelog.filteredrevs return smartset.baseset(revs) else: # slow path - enumerate all revisions phase = self.phase revs = (r for r in repo if phase(repo, r) in phases) return smartset.generatorset(revs, iterasc=True) def copy(self): # Shallow copy meant to ensure isolation in # advance/retractboundary(), nothing more. ph = self.__class__(None, None, _load=False) ph.phaseroots = self.phaseroots[:] ph.dirty = self.dirty ph.opener = self.opener ph._phaserevs = self._phaserevs ph._phasesets = self._phasesets return ph def replace(self, phcache): """replace all values in 'self' with content of phcache""" for a in ('phaseroots', 'dirty', 'opener', '_phaserevs', '_phasesets'): setattr(self, a, getattr(phcache, a)) def _getphaserevsnative(self, repo): repo = repo.unfiltered() nativeroots = [] for phase in trackedphases: nativeroots.append(map(repo.changelog.rev, self.phaseroots[phase])) return repo.changelog.computephases(nativeroots) def _computephaserevspure(self, repo): repo = repo.unfiltered() revs = [public] * len(repo.changelog) self._phaserevs = revs self._populatephaseroots(repo) for phase in trackedphases: roots = list(map(repo.changelog.rev, self.phaseroots[phase])) if roots: for rev in roots: revs[rev] = phase for rev in repo.changelog.descendants(roots): revs[rev] = phase def loadphaserevs(self, repo): """ensure phase information is loaded in the object""" if self._phaserevs is None: try: res = self._getphaserevsnative(repo) self._phaserevs, self._phasesets = res except AttributeError: self._computephaserevspure(repo) def invalidate(self): self._phaserevs = None self._phasesets = None def _populatephaseroots(self, repo): """Fills the _phaserevs cache with phases for the roots. """ cl = repo.changelog phaserevs = self._phaserevs for phase in trackedphases: roots = map(cl.rev, self.phaseroots[phase]) for root in roots: phaserevs[root] = phase def phase(self, repo, rev): # We need a repo argument here to be able to build _phaserevs # if necessary. The repository instance is not stored in # phasecache to avoid reference cycles. The changelog instance # is not stored because it is a filecache() property and can # be replaced without us being notified. if rev == nullrev: return public if rev < nullrev: raise ValueError(_('cannot lookup negative revision')) if self._phaserevs is None or rev >= len(self._phaserevs): self.invalidate() self.loadphaserevs(repo) return self._phaserevs[rev] def write(self): if not self.dirty: return f = self.opener('phaseroots', 'w', atomictemp=True, checkambig=True) try: self._write(f) finally: f.close() def _write(self, fp): for phase, roots in enumerate(self.phaseroots): for h in roots: fp.write('%i %s\n' % (phase, hex(h))) self.dirty = False def _updateroots(self, phase, newroots, tr): self.phaseroots[phase] = newroots self.invalidate() self.dirty = True tr.addfilegenerator('phase', ('phaseroots',), self._write) tr.hookargs['phases_moved'] = '1' def registernew(self, repo, tr, targetphase, nodes): repo = repo.unfiltered() self._retractboundary(repo, tr, targetphase, nodes) if tr is not None and 'phases' in tr.changes: phasetracking = tr.changes['phases'] torev = repo.changelog.rev phase = self.phase for n in nodes: rev = torev(n) revphase = phase(repo, rev) _trackphasechange(phasetracking, rev, None, revphase) repo.invalidatevolatilesets() def advanceboundary(self, repo, tr, targetphase, nodes): """Set all 'nodes' to phase 'targetphase' Nodes with a phase lower than 'targetphase' are not affected. """ # Be careful to preserve shallow-copied values: do not update # phaseroots values, replace them. if tr is None: phasetracking = None else: phasetracking = tr.changes.get('phases') repo = repo.unfiltered() delroots = [] # set of root deleted by this path for phase in xrange(targetphase + 1, len(allphases)): # filter nodes that are not in a compatible phase already nodes = [n for n in nodes if self.phase(repo, repo[n].rev()) >= phase] if not nodes: break # no roots to move anymore olds = self.phaseroots[phase] affected = repo.revs('%ln::%ln', olds, nodes) for r in affected: _trackphasechange(phasetracking, r, self.phase(repo, r), targetphase) roots = set(ctx.node() for ctx in repo.set( 'roots((%ln::) - %ld)', olds, affected)) if olds != roots: self._updateroots(phase, roots, tr) # some roots may need to be declared for lower phases delroots.extend(olds - roots) # declare deleted root in the target phase if targetphase != 0: self._retractboundary(repo, tr, targetphase, delroots) repo.invalidatevolatilesets() def retractboundary(self, repo, tr, targetphase, nodes): oldroots = self.phaseroots[:targetphase + 1] if tr is None: phasetracking = None else: phasetracking = tr.changes.get('phases') repo = repo.unfiltered() if (self._retractboundary(repo, tr, targetphase, nodes) and phasetracking is not None): # find the affected revisions new = self.phaseroots[targetphase] old = oldroots[targetphase] affected = set(repo.revs('(%ln::) - (%ln::)', new, old)) # find the phase of the affected revision for phase in xrange(targetphase, -1, -1): if phase: roots = oldroots[phase] revs = set(repo.revs('%ln::%ld', roots, affected)) affected -= revs else: # public phase revs = affected for r in revs: _trackphasechange(phasetracking, r, phase, targetphase) repo.invalidatevolatilesets() def _retractboundary(self, repo, tr, targetphase, nodes): # Be careful to preserve shallow-copied values: do not update # phaseroots values, replace them. repo = repo.unfiltered() currentroots = self.phaseroots[targetphase] finalroots = oldroots = set(currentroots) newroots = [n for n in nodes if self.phase(repo, repo[n].rev()) < targetphase] if newroots: if nullid in newroots: raise error.Abort(_('cannot change null revision phase')) currentroots = currentroots.copy() currentroots.update(newroots) # Only compute new roots for revs above the roots that are being # retracted. minnewroot = min(repo[n].rev() for n in newroots) aboveroots = [n for n in currentroots if repo[n].rev() >= minnewroot] updatedroots = repo.set('roots(%ln::)', aboveroots) finalroots = set(n for n in currentroots if repo[n].rev() < minnewroot) finalroots.update(ctx.node() for ctx in updatedroots) if finalroots != oldroots: self._updateroots(targetphase, finalroots, tr) return True return False def filterunknown(self, repo): """remove unknown nodes from the phase boundary Nothing is lost as unknown nodes only hold data for their descendants. """ filtered = False nodemap = repo.changelog.nodemap # to filter unknown nodes for phase, nodes in enumerate(self.phaseroots): missing = sorted(node for node in nodes if node not in nodemap) if missing: for mnode in missing: repo.ui.debug( 'removing unknown node %s from %i-phase boundary\n' % (short(mnode), phase)) nodes.symmetric_difference_update(missing) filtered = True if filtered: self.dirty = True # filterunknown is called by repo.destroyed, we may have no changes in # root but phaserevs contents is certainly invalid (or at least we # have not proper way to check that). related to issue 3858. # # The other caller is __init__ that have no _phaserevs initialized # anyway. If this change we should consider adding a dedicated # "destroyed" function to phasecache or a proper cache key mechanism # (see branchmap one) self.invalidate() def advanceboundary(repo, tr, targetphase, nodes): """Add nodes to a phase changing other nodes phases if necessary. This function move boundary *forward* this means that all nodes are set in the target phase or kept in a *lower* phase. Simplify boundary to contains phase roots only.""" phcache = repo._phasecache.copy() phcache.advanceboundary(repo, tr, targetphase, nodes) repo._phasecache.replace(phcache) def retractboundary(repo, tr, targetphase, nodes): """Set nodes back to a phase changing other nodes phases if necessary. This function move boundary *backward* this means that all nodes are set in the target phase or kept in a *higher* phase. Simplify boundary to contains phase roots only.""" phcache = repo._phasecache.copy() phcache.retractboundary(repo, tr, targetphase, nodes) repo._phasecache.replace(phcache) def registernew(repo, tr, targetphase, nodes): """register a new revision and its phase Code adding revisions to the repository should use this function to set new changeset in their target phase (or higher). """ phcache = repo._phasecache.copy() phcache.registernew(repo, tr, targetphase, nodes) repo._phasecache.replace(phcache) def listphases(repo): """List phases root for serialization over pushkey""" # Use ordered dictionary so behavior is deterministic. keys = util.sortdict() value = '%i' % draft for root in repo._phasecache.phaseroots[draft]: keys[hex(root)] = value if repo.publishing(): # Add an extra data to let remote know we are a publishing # repo. Publishing repo can't just pretend they are old repo. # When pushing to a publishing repo, the client still need to # push phase boundary # # Push do not only push changeset. It also push phase data. # New phase data may apply to common changeset which won't be # push (as they are common). Here is a very simple example: # # 1) repo A push changeset X as draft to repo B # 2) repo B make changeset X public # 3) repo B push to repo A. X is not pushed but the data that # X as now public should # # The server can't handle it on it's own as it has no idea of # client phase data. keys['publishing'] = 'True' return keys def pushphase(repo, nhex, oldphasestr, newphasestr): """List phases root for serialization over pushkey""" repo = repo.unfiltered() with repo.lock(): currentphase = repo[nhex].phase() newphase = abs(int(newphasestr)) # let's avoid negative index surprise oldphase = abs(int(oldphasestr)) # let's avoid negative index surprise if currentphase == oldphase and newphase < oldphase: with repo.transaction('pushkey-phase') as tr: advanceboundary(repo, tr, newphase, [bin(nhex)]) return True elif currentphase == newphase: # raced, but got correct result return True else: return False def subsetphaseheads(repo, subset): """Finds the phase heads for a subset of a history Returns a list indexed by phase number where each item is a list of phase head nodes. """ cl = repo.changelog headsbyphase = [[] for i in allphases] # No need to keep track of secret phase; any heads in the subset that # are not mentioned are implicitly secret. for phase in allphases[:-1]: revset = "heads(%%ln & %s())" % phasenames[phase] headsbyphase[phase] = [cl.node(r) for r in repo.revs(revset, subset)] return headsbyphase def updatephases(repo, tr, headsbyphase): """Updates the repo with the given phase heads""" # Now advance phase boundaries of all but secret phase for phase in allphases[:-1]: advanceboundary(repo, tr, phase, headsbyphase[phase]) def analyzeremotephases(repo, subset, roots): """Compute phases heads and root in a subset of node from root dict * subset is heads of the subset * roots is {<nodeid> => phase} mapping. key and value are string. Accept unknown element input """ repo = repo.unfiltered() # build list from dictionary draftroots = [] nodemap = repo.changelog.nodemap # to filter unknown nodes for nhex, phase in roots.iteritems(): if nhex == 'publishing': # ignore data related to publish option continue node = bin(nhex) phase = int(phase) if phase == public: if node != nullid: repo.ui.warn(_('ignoring inconsistent public root' ' from remote: %s\n') % nhex) elif phase == draft: if node in nodemap: draftroots.append(node) else: repo.ui.warn(_('ignoring unexpected root from remote: %i %s\n') % (phase, nhex)) # compute heads publicheads = newheads(repo, subset, draftroots) return publicheads, draftroots def newheads(repo, heads, roots): """compute new head of a subset minus another * `heads`: define the first subset * `roots`: define the second we subtract from the first""" repo = repo.unfiltered() revset = repo.set('heads((%ln + parents(%ln)) - (%ln::%ln))', heads, roots, roots, heads) return [c.node() for c in revset] def newcommitphase(ui): """helper to get the target phase of new commit Handle all possible values for the phases.new-commit options. """ v = ui.config('phases', 'new-commit', draft) try: return phasenames.index(v) except ValueError: try: return int(v) except ValueError: msg = _("phases.new-commit: not a valid phase name ('%s')") raise error.ConfigError(msg % v) def hassecret(repo): """utility function that check if a repo have any secret changeset.""" return bool(repo._phasecache.phaseroots[2])