text: # discovery.py - protocol changeset discovery functions
  #
  # Copyright 2010 Matt Mackall <mpm@selenic.com>
  #
  # This software may be used and distributed according to the terms of the
  # GNU General Public License version 2 or any later version.
  
  
  
  import functools
  
  from .i18n import _
  from .node import (
      hex,
      nullid,
      short,
  )
  
  from . import (
      bookmarks,
      branchmap,
      error,
      phases,
      setdiscovery,
      treediscovery,
      util,
  )
  
  def findcommonincoming(repo, remote, heads=None, force=False):
      """Return a tuple (common, anyincoming, heads) used to identify the common
      subset of nodes between repo and remote.
  
      "common" is a list of (at least) the heads of the common subset.
      "anyincoming" is testable as a boolean indicating if any nodes are missing
        locally. If remote does not support getbundle, this actually is a list of
        roots of the nodes that would be incoming, to be supplied to
        changegroupsubset. No code except for pull should be relying on this fact
        any longer.
      "heads" is either the supplied heads, or else the remote's heads.
  
      If you pass heads and they are all known locally, the response lists just
      these heads in "common" and in "heads".
  
      Please use findcommonoutgoing to compute the set of outgoing nodes to give
      extensions a good hook into outgoing.
      """
  
      if not remote.capable('getbundle'):
          return treediscovery.findcommonincoming(repo, remote, heads, force)
  
      if heads:
          allknown = True
          knownnode = repo.changelog.hasnode # no nodemap until it is filtered
          for h in heads:
              if not knownnode(h):
                  allknown = False
                  break
          if allknown:
              return (heads, False, heads)
  
      res = setdiscovery.findcommonheads(repo.ui, repo, remote,
                                         abortwhenunrelated=not force)
      common, anyinc, srvheads = res
      return (list(common), anyinc, heads or list(srvheads))
  
  class outgoing(object):
      '''Represents the set of nodes present in a local repo but not in a
      (possibly) remote one.
  
      Members:
  
        missing is a list of all nodes present in local but not in remote.
        common is a list of all nodes shared between the two repos.
        excluded is the list of missing changeset that shouldn't be sent remotely.
        missingheads is the list of heads of missing.
        commonheads is the list of heads of common.
  
      The sets are computed on demand from the heads, unless provided upfront
      by discovery.'''
  
      def __init__(self, repo, commonheads=None, missingheads=None,
                   missingroots=None):
          # at least one of them must not be set
          assert None in (commonheads, missingroots)
          cl = repo.changelog
          if missingheads is None:
              missingheads = cl.heads()
          if missingroots:
              discbases = []
              for n in missingroots:
                  discbases.extend([p for p in cl.parents(n) if p != nullid])
              # TODO remove call to nodesbetween.
              # TODO populate attributes on outgoing instance instead of setting
              # discbases.
              csets, roots, heads = cl.nodesbetween(missingroots, missingheads)
              included = set(csets)
              missingheads = heads
              commonheads = [n for n in discbases if n not in included]
          elif not commonheads:
              commonheads = [nullid]
          self.commonheads = commonheads
          self.missingheads = missingheads
          self._revlog = cl
          self._common = None
          self._missing = None
          self.excluded = []
  
      def _computecommonmissing(self):
          sets = self._revlog.findcommonmissing(self.commonheads,
                                                self.missingheads)
          self._common, self._missing = sets
  
      @util.propertycache
      def common(self):
          if self._common is None:
              self._computecommonmissing()
          return self._common
  
      @util.propertycache
      def missing(self):
          if self._missing is None:
              self._computecommonmissing()
          return self._missing
  
  def findcommonoutgoing(repo, other, onlyheads=None, force=False,
                         commoninc=None, portable=False):
      '''Return an outgoing instance to identify the nodes present in repo but
      not in other.
  
      If onlyheads is given, only nodes ancestral to nodes in onlyheads
      (inclusive) are included. If you already know the local repo's heads,
      passing them in onlyheads is faster than letting them be recomputed here.
  
      If commoninc is given, it must be the result of a prior call to
      findcommonincoming(repo, other, force) to avoid recomputing it here.
  
      If portable is given, compute more conservative common and missingheads,
      to make bundles created from the instance more portable.'''
      # declare an empty outgoing object to be filled later
      og = outgoing(repo, None, None)
  
      # get common set if not provided
      if commoninc is None:
          commoninc = findcommonincoming(repo, other, force=force)
      og.commonheads, _any, _hds = commoninc
  
      # compute outgoing
      mayexclude = (repo._phasecache.phaseroots[phases.secret] or repo.obsstore)
      if not mayexclude:
          og.missingheads = onlyheads or repo.heads()
      elif onlyheads is None:
          # use visible heads as it should be cached
          og.missingheads = repo.filtered("served").heads()
          og.excluded = [ctx.node() for ctx in repo.set('secret() or extinct()')]
      else:
          # compute common, missing and exclude secret stuff
          sets = repo.changelog.findcommonmissing(og.commonheads, onlyheads)
          og._common, allmissing = sets
          og._missing = missing = []
          og.excluded = excluded = []
          for node in allmissing:
              ctx = repo[node]
              if ctx.phase() >= phases.secret or ctx.extinct():
                  excluded.append(node)
              else:
                  missing.append(node)
          if len(missing) == len(allmissing):
              missingheads = onlyheads
          else: # update missing heads
              missingheads = phases.newheads(repo, onlyheads, excluded)
          og.missingheads = missingheads
      if portable:
          # recompute common and missingheads as if -r<rev> had been given for
          # each head of missing, and --base <rev> for each head of the proper
          # ancestors of missing
          og._computecommonmissing()
          cl = repo.changelog
          missingrevs = set(cl.rev(n) for n in og._missing)
          og._common = set(cl.ancestors(missingrevs)) - missingrevs
          commonheads = set(og.commonheads)
          og.missingheads = [h for h in og.missingheads if h not in commonheads]
  
      return og
  
  def _headssummary(pushop):
      """compute a summary of branch and heads status before and after push
  
      return {'branch': ([remoteheads], [newheads],
                         [unsyncedheads], [discardedheads])} mapping
  
      - branch: the branch name,
      - remoteheads: the list of remote heads known locally
                     None if the branch is new,
      - newheads: the new remote heads (known locally) with outgoing pushed,
      - unsyncedheads: the list of remote heads unknown locally,
      - discardedheads: the list of heads made obsolete by the push.
      """
      repo = pushop.repo.unfiltered()
      remote = pushop.remote
      outgoing = pushop.outgoing
      cl = repo.changelog
      headssum = {}
      # A. Create set of branches involved in the push.
      branches = set(repo[n].branch() for n in outgoing.missing)
      remotemap = remote.branchmap()
      newbranches = branches - set(remotemap)
      branches.difference_update(newbranches)
  
      # A. register remote heads
      remotebranches = set()
      for branch, heads in remote.branchmap().items():
          remotebranches.add(branch)
          known = []
          unsynced = []
          knownnode = cl.hasnode # do not use nodemap until it is filtered
          for h in heads:
              if knownnode(h):
                  known.append(h)
              else:
                  unsynced.append(h)
          headssum[branch] = (known, list(known), unsynced)
      # B. add new branch data
      missingctx = list(repo[n] for n in outgoing.missing)
      touchedbranches = set()
      for ctx in missingctx:
          branch = ctx.branch()
          touchedbranches.add(branch)
          if branch not in headssum:
              headssum[branch] = (None, [], [])
  
      # C drop data about untouched branches:
      for branch in remotebranches - touchedbranches:
          del headssum[branch]
  
      # D. Update newmap with outgoing changes.
      # This will possibly add new heads and remove existing ones.
      newmap = branchmap.branchcache((branch, heads[1])
                                   for branch, heads in headssum.items()
                                   if heads[0] is not None)
      newmap.update(repo, (ctx.rev() for ctx in missingctx))
      for branch, newheads in newmap.items():
          headssum[branch][1][:] = newheads
      for branch, items in headssum.items():
          for l in items:
              if l is not None:
                  l.sort()
          headssum[branch] = items + ([],)
  
      # If there are no obsstore, no post processing are needed.
      if repo.obsstore:
          torev = repo.changelog.rev
          futureheads = set(torev(h) for h in outgoing.missingheads)
          futureheads |= set(torev(h) for h in outgoing.commonheads)
          allfuturecommon = repo.changelog.ancestors(futureheads, inclusive=True)
          for branch, heads in sorted(headssum.items()):
              remoteheads, newheads, unsyncedheads, placeholder = heads
              result = _postprocessobsolete(pushop, allfuturecommon, newheads)
              headssum[branch] = (remoteheads, sorted(result[0]), unsyncedheads,
                                  sorted(result[1]))
      return headssum
  
  def _oldheadssummary(repo, remoteheads, outgoing, inc=False):
      """Compute branchmapsummary for repo without branchmap support"""
  
      # 1-4b. old servers: Check for new topological heads.
      # Construct {old,new}map with branch = None (topological branch).
      # (code based on update)
      knownnode = repo.changelog.hasnode # no nodemap until it is filtered
      oldheads = sorted(h for h in remoteheads if knownnode(h))
      # all nodes in outgoing.missing are children of either:
      # - an element of oldheads
      # - another element of outgoing.missing
      # - nullrev
      # This explains why the new head are very simple to compute.
      r = repo.set('heads(%ln + %ln)', oldheads, outgoing.missing)
      newheads = sorted(c.node() for c in r)
      # set some unsynced head to issue the "unsynced changes" warning
      if inc:
          unsynced = [None]
      else:
          unsynced = []
      return {None: (oldheads, newheads, unsynced, [])}
  
  def _nowarnheads(pushop):
      # Compute newly pushed bookmarks. We don't warn about bookmarked heads.
      repo = pushop.repo.unfiltered()
      remote = pushop.remote
      localbookmarks = repo._bookmarks
      remotebookmarks = remote.listkeys('bookmarks')
      bookmarkedheads = set()
  
      # internal config: bookmarks.pushing
      newbookmarks = [localbookmarks.expandname(b)
                      for b in pushop.ui.configlist('bookmarks', 'pushing')]
  
      for bm in localbookmarks:
          rnode = remotebookmarks.get(bm)
          if rnode and rnode in repo:
              lctx, rctx = repo[bm], repo[rnode]
              if bookmarks.validdest(repo, rctx, lctx):
                  bookmarkedheads.add(lctx.node())
          else:
              if bm in newbookmarks and bm not in remotebookmarks:
                  bookmarkedheads.add(repo[bm].node())
  
      return bookmarkedheads
  
  def checkheads(pushop):
      """Check that a push won't add any outgoing head
  
      raise Abort error and display ui message as needed.
      """
  
      repo = pushop.repo.unfiltered()
      remote = pushop.remote
      outgoing = pushop.outgoing
      remoteheads = pushop.remoteheads
      newbranch = pushop.newbranch
      inc = bool(pushop.incoming)
  
      # Check for each named branch if we're creating new remote heads.
      # To be a remote head after push, node must be either:
      # - unknown locally
      # - a local outgoing head descended from update
      # - a remote head that's known locally and not
      #   ancestral to an outgoing head
      if remoteheads == [nullid]:
          # remote is empty, nothing to check.
          return
  
      if remote.capable('branchmap'):
          headssum = _headssummary(pushop)
      else:
          headssum = _oldheadssummary(repo, remoteheads, outgoing, inc)
      pushop.pushbranchmap = headssum
      newbranches = [branch for branch, heads in headssum.items()
                     if heads[0] is None]
      # 1. Check for new branches on the remote.
      if newbranches and not newbranch:  # new branch requires --new-branch
          branchnames = ', '.join(sorted(newbranches))
          raise error.Abort(_("push creates new remote branches: %s!")
                             % branchnames,
                           hint=_("use 'hg push --new-branch' to create"
                                  " new remote branches"))
  
      # 2. Find heads that we need not warn about
      nowarnheads = _nowarnheads(pushop)
  
      # 3. Check for new heads.
      # If there are more heads after the push than before, a suitable
      # error message, depending on unsynced status, is displayed.
      errormsg = None
      for branch, heads in sorted(headssum.items()):
          remoteheads, newheads, unsyncedheads, discardedheads = heads
          # add unsynced data
          if remoteheads is None:
              oldhs = set()
          else:
              oldhs = set(remoteheads)
          oldhs.update(unsyncedheads)
          dhs = None # delta heads, the new heads on branch
          newhs = set(newheads)
          newhs.update(unsyncedheads)
          if unsyncedheads:
              if None in unsyncedheads:
                  # old remote, no heads data
                  heads = None
              elif len(unsyncedheads) <= 4 or repo.ui.verbose:
                  heads = ' '.join(short(h) for h in unsyncedheads)
              else:
                  heads = (' '.join(short(h) for h in unsyncedheads[:4]) +
                           ' ' + _("and %s others") % (len(unsyncedheads) - 4))
              if heads is None:
                  repo.ui.status(_("remote has heads that are "
                                   "not known locally\n"))
              elif branch is None:
                  repo.ui.status(_("remote has heads that are "
                                   "not known locally: %s\n") % heads)
              else:
                  repo.ui.status(_("remote has heads on branch '%s' that are "
                                   "not known locally: %s\n") % (branch, heads))
          if remoteheads is None:
              if len(newhs) > 1:
                  dhs = list(newhs)
                  if errormsg is None:
                      errormsg = (_("push creates new branch '%s' "
                                    "with multiple heads") % (branch))
                      hint = _("merge or"
                               " see 'hg help push' for details about"
                               " pushing new heads")
          elif len(newhs) > len(oldhs):
              # remove bookmarked or existing remote heads from the new heads list
              dhs = sorted(newhs - nowarnheads - oldhs)
          if dhs:
              if errormsg is None:
                  if branch not in ('default', None):
                      errormsg = _("push creates new remote head %s "
                                   "on branch '%s'!") % (short(dhs[0]), branch)
                  elif repo[dhs[0]].bookmarks():
                      errormsg = _("push creates new remote head %s "
                                   "with bookmark '%s'!") % (
                                   short(dhs[0]), repo[dhs[0]].bookmarks()[0])
                  else:
                      errormsg = _("push creates new remote head %s!"
                                   ) % short(dhs[0])
                  if unsyncedheads:
                      hint = _("pull and merge or"
                               " see 'hg help push' for details about"
                               " pushing new heads")
                  else:
                      hint = _("merge or"
                               " see 'hg help push' for details about"
                               " pushing new heads")
              if branch is None:
                  repo.ui.note(_("new remote heads:\n"))
              else:
                  repo.ui.note(_("new remote heads on branch '%s':\n") % branch)
              for h in dhs:
                  repo.ui.note((" %s\n") % short(h))
      if errormsg:
          raise error.Abort(errormsg, hint=hint)
  
  def _postprocessobsolete(pushop, futurecommon, candidate_newhs):
      """post process the list of new heads with obsolescence information
  
      Exists as a sub-function to contain the complexity and allow extensions to
      experiment with smarter logic.
  
      Returns (newheads, discarded_heads) tuple
      """
      # known issue
      #
      # * We "silently" skip processing on all changeset unknown locally
      #
      # * if <nh> is public on the remote, it won't be affected by obsolete
      #     marker and a new is created
  
      # define various utilities and containers
      repo = pushop.repo
      unfi = repo.unfiltered()
      tonode = unfi.changelog.node
      torev = unfi.changelog.nodemap.get
      public = phases.public
      getphase = unfi._phasecache.phase
      ispublic = (lambda r: getphase(unfi, r) == public)
      ispushed = (lambda n: torev(n) in futurecommon)
      hasoutmarker = functools.partial(pushingmarkerfor, unfi.obsstore, ispushed)
      successorsmarkers = unfi.obsstore.successors
      newhs = set() # final set of new heads
      discarded = set() # new head of fully replaced branch
  
      localcandidate = set() # candidate heads known locally
      unknownheads = set() # candidate heads unknown locally
      for h in candidate_newhs:
          if h in unfi:
              localcandidate.add(h)
          else:
              if successorsmarkers.get(h) is not None:
                  msg = ('checkheads: remote head unknown locally has'
                         ' local marker: %s\n')
                  repo.ui.debug(msg % hex(h))
              unknownheads.add(h)
  
      # fast path the simple case
      if len(localcandidate) == 1:
          return unknownheads | set(candidate_newhs), set()
  
      # actually process branch replacement
      while localcandidate:
          nh = localcandidate.pop()
          # run this check early to skip the evaluation of the whole branch
          if (torev(nh) in futurecommon or ispublic(torev(nh))):
              newhs.add(nh)
              continue
  
          # Get all revs/nodes on the branch exclusive to this head
          # (already filtered heads are "ignored"))
          branchrevs = unfi.revs('only(%n, (%ln+%ln))',
                                 nh, localcandidate, newhs)
          branchnodes = [tonode(r) for r in branchrevs]
  
          # The branch won't be hidden on the remote if
          # * any part of it is public,
          # * any part of it is considered part of the result by previous logic,
          # * if we have no markers to push to obsolete it.
          if (any(ispublic(r) for r in branchrevs)
                  or any(torev(n) in futurecommon for n in branchnodes)
                  or any(not hasoutmarker(n) for n in branchnodes)):
              newhs.add(nh)
          else:
              # note: there is a corner case if there is a merge in the branch.
              # we might end up with -more- heads.  However, these heads are not
              # "added" by the push, but more by the "removal" on the remote so I
              # think is a okay to ignore them,
              discarded.add(nh)
      newhs |= unknownheads
      return newhs, discarded
  
  def pushingmarkerfor(obsstore, ispushed, node):
      """true if some markers are to be pushed for node
  
      We cannot just look in to the pushed obsmarkers from the pushop because
      discovery might have filtered relevant markers. In addition listing all
      markers relevant to all changesets in the pushed set would be too expensive
      (O(len(repo)))
  
      (note: There are cache opportunity in this function. but it would requires
      a two dimensional stack.)
      """
      successorsmarkers = obsstore.successors
      stack = [node]
      seen = set(stack)
      while stack:
          current = stack.pop()
          if ispushed(current):
              return True
          markers = successorsmarkers.get(current, ())
          # markers fields = ('prec', 'succs', 'flag', 'meta', 'date', 'parents')
          for m in markers:
              nexts = m[1] # successors
              if not nexts: # this is a prune marker
                  nexts = m[5] or () # parents
              for n in nexts:
                  if n not in seen:
                      seen.add(n)
                      stack.append(n)
      return False
  