pull: move transaction logic into the pull object

Most local change that occurs during a pull are doing within a `transaction`.
Currently this mean (1) adding new changeset (2) adding obsolescence markers. We
want the two operations to be done in the same transaction. However we do not
want to create a transaction if nothing is added to the repo. Creating an empty
transaction would drop the previous transaction data and confuse tool and people
who are still using rollback.

So the current pull code has some logic to create and handle this transaction on
demand. We are moving this logic in to the `pulloperation` object itself to
simplify this lazy creation logic through all different par of the push.

Note that, in the future, other part of pull (phases, bookmark) will probably
want to be part of the transaction too.

mercurial/exchange.py

@@ -1,506 +1,516 b''
 # exchange.py - utily to exchange data between repo.
 #
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from i18n import _
 from node import hex, nullid
 import errno
 import util, scmutil, changegroup, base85
 import discovery, phases, obsolete, bookmarks
 
 
 class pushoperation(object):
     """A object that represent a single push operation
 
     It purpose is to carry push related state and very common operation.
 
     A new should be created at the begining of each push and discarded
     afterward.
     """
 
     def __init__(self, repo, remote, force=False, revs=None, newbranch=False):
         # repo we push from
         self.repo = repo
         self.ui = repo.ui
         # repo we push to
         self.remote = remote
         # force option provided
         self.force = force
         # revs to be pushed (None is "all")
         self.revs = revs
         # allow push of new branch
         self.newbranch = newbranch
         # did a local lock get acquired?
         self.locallocked = None
         # Integer version of the push result
         # - None means nothing to push
         # - 0 means HTTP error
         # - 1 means we pushed and remote head count is unchanged *or*
         #   we have outgoing changesets but refused to push
         # - other values as described by addchangegroup()
         self.ret = None
         # discover.outgoing object (contains common and outgoin data)
         self.outgoing = None
         # all remote heads before the push
         self.remoteheads = None
         # testable as a boolean indicating if any nodes are missing locally.
         self.incoming = None
         # set of all heads common after changeset bundle push
         self.commonheads = None
 
 def push(repo, remote, force=False, revs=None, newbranch=False):
     '''Push outgoing changesets (limited by revs) from a local
     repository to remote. Return an integer:
       - None means nothing to push
       - 0 means HTTP error
       - 1 means we pushed and remote head count is unchanged *or*
         we have outgoing changesets but refused to push
       - other values as described by addchangegroup()
     '''
     pushop = pushoperation(repo, remote, force, revs, newbranch)
     if pushop.remote.local():
         missing = (set(pushop.repo.requirements)
                    - pushop.remote.local().supported)
         if missing:
             msg = _("required features are not"
                     " supported in the destination:"
                     " %s") % (', '.join(sorted(missing)))
             raise util.Abort(msg)
 
     # there are two ways to push to remote repo:
     #
     # addchangegroup assumes local user can lock remote
     # repo (local filesystem, old ssh servers).
     #
     # unbundle assumes local user cannot lock remote repo (new ssh
     # servers, http servers).
 
     if not pushop.remote.canpush():
         raise util.Abort(_("destination does not support push"))
     # get local lock as we might write phase data
     locallock = None
     try:
         locallock = pushop.repo.lock()
         pushop.locallocked = True
     except IOError, err:
         pushop.locallocked = False
         if err.errno != errno.EACCES:
             raise
         # source repo cannot be locked.
         # We do not abort the push, but just disable the local phase
         # synchronisation.
         msg = 'cannot lock source repository: %s\n' % err
         pushop.ui.debug(msg)
     try:
         pushop.repo.checkpush(pushop.force, pushop.revs)
         lock = None
         unbundle = pushop.remote.capable('unbundle')
         if not unbundle:
             lock = pushop.remote.lock()
         try:
             _pushdiscovery(pushop)
             if _pushcheckoutgoing(pushop):
                 _pushchangeset(pushop)
             _pushcomputecommonheads(pushop)
             _pushsyncphase(pushop)
             _pushobsolete(pushop)
         finally:
             if lock is not None:
                 lock.release()
     finally:
         if locallock is not None:
             locallock.release()
 
     _pushbookmark(pushop)
     return pushop.ret
 
 def _pushdiscovery(pushop):
     # discovery
     unfi = pushop.repo.unfiltered()
     fci = discovery.findcommonincoming
     commoninc = fci(unfi, pushop.remote, force=pushop.force)
     common, inc, remoteheads = commoninc
     fco = discovery.findcommonoutgoing
     outgoing = fco(unfi, pushop.remote, onlyheads=pushop.revs,
                    commoninc=commoninc, force=pushop.force)
     pushop.outgoing = outgoing
     pushop.remoteheads = remoteheads
     pushop.incoming = inc
 
 def _pushcheckoutgoing(pushop):
     outgoing = pushop.outgoing
     unfi = pushop.repo.unfiltered()
     if not outgoing.missing:
         # nothing to push
         scmutil.nochangesfound(unfi.ui, unfi, outgoing.excluded)
         return False
     # something to push
     if not pushop.force:
         # if repo.obsstore == False --> no obsolete
         # then, save the iteration
         if unfi.obsstore:
             # this message are here for 80 char limit reason
             mso = _("push includes obsolete changeset: %s!")
             mst = "push includes %s changeset: %s!"
             # plain versions for i18n tool to detect them
             _("push includes unstable changeset: %s!")
             _("push includes bumped changeset: %s!")
             _("push includes divergent changeset: %s!")
             # If we are to push if there is at least one
             # obsolete or unstable changeset in missing, at
             # least one of the missinghead will be obsolete or
             # unstable. So checking heads only is ok
             for node in outgoing.missingheads:
                 ctx = unfi[node]
                 if ctx.obsolete():
                     raise util.Abort(mso % ctx)
                 elif ctx.troubled():
                     raise util.Abort(_(mst)
                                      % (ctx.troubles()[0],
                                         ctx))
         newbm = pushop.ui.configlist('bookmarks', 'pushing')
         discovery.checkheads(unfi, pushop.remote, outgoing,
                              pushop.remoteheads,
                              pushop.newbranch,
                              bool(pushop.incoming),
                              newbm)
     return True
 
 def _pushchangeset(pushop):
     """Make the actual push of changeset bundle to remote repo"""
     outgoing = pushop.outgoing
     unbundle = pushop.remote.capable('unbundle')
     # TODO: get bundlecaps from remote
     bundlecaps = None
     # create a changegroup from local
     if pushop.revs is None and not (outgoing.excluded
                             or pushop.repo.changelog.filteredrevs):
         # push everything,
         # use the fast path, no race possible on push
         bundler = changegroup.bundle10(pushop.repo, bundlecaps)
         cg = pushop.repo._changegroupsubset(outgoing,
                                             bundler,
                                             'push',
                                             fastpath=True)
     else:
         cg = pushop.repo.getlocalbundle('push', outgoing, bundlecaps)
 
     # apply changegroup to remote
     if unbundle:
         # local repo finds heads on server, finds out what
         # revs it must push. once revs transferred, if server
         # finds it has different heads (someone else won
         # commit/push race), server aborts.
         if pushop.force:
             remoteheads = ['force']
         else:
             remoteheads = pushop.remoteheads
         # ssh: return remote's addchangegroup()
         # http: return remote's addchangegroup() or 0 for error
         pushop.ret = pushop.remote.unbundle(cg, remoteheads,
                                             'push')
     else:
         # we return an integer indicating remote head count
         # change
         pushop.ret = pushop.remote.addchangegroup(cg, 'push',
                                                               pushop.repo.url())
 
 def _pushcomputecommonheads(pushop):
     unfi = pushop.repo.unfiltered()
     if pushop.ret:
         # push succeed, synchronize target of the push
         cheads = pushop.outgoing.missingheads
     elif pushop.revs is None:
         # All out push fails. synchronize all common
         cheads = pushop.outgoing.commonheads
     else:
         # I want cheads = heads(::missingheads and ::commonheads)
         # (missingheads is revs with secret changeset filtered out)
         #
         # This can be expressed as:
         #     cheads = ( (missingheads and ::commonheads)
         #              + (commonheads and ::missingheads))"
         #              )
         #
         # while trying to push we already computed the following:
         #     common = (::commonheads)
         #     missing = ((commonheads::missingheads) - commonheads)
         #
         # We can pick:
         # * missingheads part of common (::commonheads)
         common = set(pushop.outgoing.common)
         nm = pushop.repo.changelog.nodemap
         cheads = [node for node in pushop.revs if nm[node] in common]
         # and
         # * commonheads parents on missing
         revset = unfi.set('%ln and parents(roots(%ln))',
                          pushop.outgoing.commonheads,
                          pushop.outgoing.missing)
         cheads.extend(c.node() for c in revset)
     pushop.commonheads = cheads
 
 def _pushsyncphase(pushop):
     """synchronise phase information locally and remotly"""
     unfi = pushop.repo.unfiltered()
     cheads = pushop.commonheads
     if pushop.ret:
         # push succeed, synchronize target of the push
         cheads = pushop.outgoing.missingheads
     elif pushop.revs is None:
         # All out push fails. synchronize all common
         cheads = pushop.outgoing.commonheads
     else:
         # I want cheads = heads(::missingheads and ::commonheads)
         # (missingheads is revs with secret changeset filtered out)
         #
         # This can be expressed as:
         #     cheads = ( (missingheads and ::commonheads)
         #              + (commonheads and ::missingheads))"
         #              )
         #
         # while trying to push we already computed the following:
         #     common = (::commonheads)
         #     missing = ((commonheads::missingheads) - commonheads)
         #
         # We can pick:
         # * missingheads part of common (::commonheads)
         common = set(pushop.outgoing.common)
         nm = pushop.repo.changelog.nodemap
         cheads = [node for node in pushop.revs if nm[node] in common]
         # and
         # * commonheads parents on missing
         revset = unfi.set('%ln and parents(roots(%ln))',
                          pushop.outgoing.commonheads,
                          pushop.outgoing.missing)
         cheads.extend(c.node() for c in revset)
     pushop.commonheads = cheads
     # even when we don't push, exchanging phase data is useful
     remotephases = pushop.remote.listkeys('phases')
     if (pushop.ui.configbool('ui', '_usedassubrepo', False)
         and remotephases    # server supports phases
         and pushop.ret is None # nothing was pushed
         and remotephases.get('publishing', False)):
         # When:
         # - this is a subrepo push
         # - and remote support phase
         # - and no changeset was pushed
         # - and remote is publishing
         # We may be in issue 3871 case!
         # We drop the possible phase synchronisation done by
         # courtesy to publish changesets possibly locally draft
         # on the remote.
         remotephases = {'publishing': 'True'}
     if not remotephases: # old server or public only rer
         _localphasemove(pushop, cheads)
         # don't push any phase data as there is nothing to push
     else:
         ana = phases.analyzeremotephases(pushop.repo, cheads,
                                          remotephases)
         pheads, droots = ana
         ### Apply remote phase on local
         if remotephases.get('publishing', False):
             _localphasemove(pushop, cheads)
         else: # publish = False
             _localphasemove(pushop, pheads)
             _localphasemove(pushop, cheads, phases.draft)
         ### Apply local phase on remote
 
         # Get the list of all revs draft on remote by public here.
         # XXX Beware that revset break if droots is not strictly
         # XXX root we may want to ensure it is but it is costly
         outdated =  unfi.set('heads((%ln::%ln) and public())',
                              droots, cheads)
         for newremotehead in outdated:
             r = pushop.remote.pushkey('phases',
                                       newremotehead.hex(),
                                       str(phases.draft),
                                       str(phases.public))
             if not r:
                 pushop.ui.warn(_('updating %s to public failed!\n')
                                        % newremotehead)
 
 def _localphasemove(pushop, nodes, phase=phases.public):
     """move <nodes> to <phase> in the local source repo"""
     if pushop.locallocked:
         phases.advanceboundary(pushop.repo, phase, nodes)
     else:
         # repo is not locked, do not change any phases!
         # Informs the user that phases should have been moved when
         # applicable.
         actualmoves = [n for n in nodes if phase < pushop.repo[n].phase()]
         phasestr = phases.phasenames[phase]
         if actualmoves:
             pushop.ui.status(_('cannot lock source repo, skipping '
                                'local %s phase update\n') % phasestr)
 
 def _pushobsolete(pushop):
     """utility function to push obsolete markers to a remote"""
     pushop.ui.debug('try to push obsolete markers to remote\n')
     repo = pushop.repo
     remote = pushop.remote
     if (obsolete._enabled and repo.obsstore and
         'obsolete' in remote.listkeys('namespaces')):
         rslts = []
         remotedata = repo.listkeys('obsolete')
         for key in sorted(remotedata, reverse=True):
             # reverse sort to ensure we end with dump0
             data = remotedata[key]
             rslts.append(remote.pushkey('obsolete', key, '', data))
         if [r for r in rslts if not r]:
             msg = _('failed to push some obsolete markers!\n')
             repo.ui.warn(msg)
 
 def _pushbookmark(pushop):
     """Update bookmark position on remote"""
     ui = pushop.ui
     repo = pushop.repo.unfiltered()
     remote = pushop.remote
     ui.debug("checking for updated bookmarks\n")
     revnums = map(repo.changelog.rev, pushop.revs or [])
     ancestors = [a for a in repo.changelog.ancestors(revnums, inclusive=True)]
     (addsrc, adddst, advsrc, advdst, diverge, differ, invalid
      ) = bookmarks.compare(repo, repo._bookmarks, remote.listkeys('bookmarks'),
                            srchex=hex)
 
     for b, scid, dcid in advsrc:
         if ancestors and repo[scid].rev() not in ancestors:
             continue
         if remote.pushkey('bookmarks', b, dcid, scid):
             ui.status(_("updating bookmark %s\n") % b)
         else:
             ui.warn(_('updating bookmark %s failed!\n') % b)
 
 class pulloperation(object):
     """A object that represent a single pull operation
 
     It purpose is to carry push related state and very common operation.
 
     A new should be created at the begining of each push and discarded
     afterward.
     """
 
     def __init__(self, repo, remote, heads=None, force=False):
         # repo we pull from
         self.repo = repo
         # repo we pull to
         self.remote = remote
         # revision we try to pull (None is "all")
         self.heads = heads
         # do we force pull?
         self.force = force
+        # the name the pull transaction
+        self._trname = 'pull\n' + util.hidepassword(remote.url())
+        # hold the transaction once created
+        self._tr = None
+
+    def gettransaction(self):
+        """get appropriate pull transaction, creating it if needed"""
+        if self._tr is None:
+            self._tr = self.repo.transaction(self._trname)
+        return self._tr
+
+    def closetransaction(self):
+        """close transaction if created"""
+        if self._tr is not None:
+            self._tr.close()
+
+    def releasetransaction(self):
+        """release transaction if created"""
+        if self._tr is not None:
+            self._tr.release()
 
 def pull(repo, remote, heads=None, force=False):
     pullop = pulloperation(repo, remote, heads, force)
     if pullop.remote.local():
         missing = set(pullop.remote.requirements) - pullop.repo.supported
         if missing:
             msg = _("required features are not"
                     " supported in the destination:"
                     " %s") % (', '.join(sorted(missing)))
             raise util.Abort(msg)
 
-    # don't open transaction for nothing or you break future useful
-    # rollback call
-    tr = None
-    trname = 'pull\n' + util.hidepassword(pullop.remote.url())
     lock = pullop.repo.lock()
     try:
         tmp = discovery.findcommonincoming(pullop.repo.unfiltered(),
                                            pullop.remote,
                                            heads=pullop.heads,
                                            force=force)
         common, fetch, rheads = tmp
         if not fetch:
             pullop.repo.ui.status(_("no changes found\n"))
             result = 0
         else:
-            tr = pullop.repo.transaction(trname)
+            # We delay the open of the transaction as late as possible so we
+            # don't open transaction for nothing or you break future useful
+            # rollback call
+            pullop.gettransaction()
             if pullop.heads is None and list(common) == [nullid]:
                 pullop.repo.ui.status(_("requesting all changes\n"))
             elif (pullop.heads is None
                   and pullop.remote.capable('changegroupsubset')):
                 # issue1320, avoid a race if remote changed after discovery
                 pullop.heads = rheads
 
             if pullop.remote.capable('getbundle'):
                 # TODO: get bundlecaps from remote
                 cg = pullop.remote.getbundle('pull', common=common,
                                              heads=pullop.heads or rheads)
             elif pullop.heads is None:
                 cg = pullop.remote.changegroup(fetch, 'pull')
             elif not pullop.remote.capable('changegroupsubset'):
                 raise util.Abort(_("partial pull cannot be done because "
                                        "other repository doesn't support "
                                        "changegroupsubset."))
             else:
                 cg = pullop.remote.changegroupsubset(fetch, pullop.heads,
                                                      'pull')
             result = pullop.repo.addchangegroup(cg, 'pull',
                                                 pullop.remote.url())
 
         # compute target subset
         if pullop.heads is None:
             # We pulled every thing possible
             # sync on everything common
             subset = common + rheads
         else:
             # We pulled a specific subset
             # sync on this subset
             subset = pullop.heads
 
         # Get remote phases data from remote
         remotephases = pullop.remote.listkeys('phases')
         publishing = bool(remotephases.get('publishing', False))
         if remotephases and not publishing:
             # remote is new and unpublishing
             pheads, _dr = phases.analyzeremotephases(pullop.repo, subset,
                                                      remotephases)
             phases.advanceboundary(pullop.repo, phases.public, pheads)
             phases.advanceboundary(pullop.repo, phases.draft, subset)
         else:
             # Remote is old or publishing all common changesets
             # should be seen as public
             phases.advanceboundary(pullop.repo, phases.public, subset)
 
-        def gettransaction():
-            if tr is None:
-                return pullop.repo.transaction(trname)
-            return tr
-
-        obstr = _pullobsolete(pullop.repo, pullop.remote, gettransaction)
-        if obstr is not None:
-            tr = obstr
-
-        if tr is not None:
-            tr.close()
+        _pullobsolete(pullop.repo, pullop.remote,
+                      pullop.gettransaction)
+        pullop.closetransaction()
     finally:
-        if tr is not None:
-            tr.release()
+        pullop.releasetransaction()
         lock.release()
 
     return result
 
 def _pullobsolete(repo, remote, gettransaction):
     """utility function to pull obsolete markers from a remote
 
     The `gettransaction` is function that return the pull transaction, creating
     one if necessary. We return the transaction to inform the calling code that
     a new transaction have been created (when applicable).
 
     Exists mostly to allow overriding for experimentation purpose"""
     tr = None
     if obsolete._enabled:
         repo.ui.debug('fetching remote obsolete markers\n')
         remoteobs = remote.listkeys('obsolete')
         if 'dump0' in remoteobs:
             tr = gettransaction()
             for key in sorted(remoteobs, reverse=True):
                 if key.startswith('dump'):
                     data = base85.b85decode(remoteobs[key])
                     repo.obsstore.mergemarkers(tr, data)
             repo.invalidatevolatilesets()
     return tr