view mercurial/treediscovery.py @ 34852:d45236f3d38e

log: add obsfate by default in changeset printer

Having an obsfate by default in log will be useful for users to understand why
they have obsolete and unstable changesets. Obsfate will only be shown for
obsolete changesets, which only happens if people opt-in to experimental feature.

But when obsolete changeset are visible, it is very useful to understand where
they are. Having it in log could be sufficient for most people, so they don't
have to learn a new command (like obslog which is itself useful in case of
divergences).

For example, when pulling and working directory parent become obsolete:

  $ hg pull
  ...
  working directory parent is obsolete! (f936c1697205)

This message comes from the Evolve extension.

Obsfate would comes handy:

  $ hg log -G
  o  changeset:   2:6f91013c5136
  |  tag:         tip
  |  parent:      0:4ef7b558f3ec
  |  user:        Boris Feld <[e-mail]>
  |  date:        Mon Oct 09 16:00:27 2017 +0200
  |  summary:     A
  |
  | @  changeset:   1:f936c1697205
  |/   user:        Boris Feld <[e-mail]>
  |    date:        Mon Oct 09 16:00:27 2017 +0200
  |    obsfate:     rewritten using amend as 2:6f91013c5136
  |    summary:     -A
  |
  o  changeset:   0:feb4dd822b8c
     user:        Boris Feld <[e-mail]>
     date:        Tue Oct 09 16:00:00 2017 +0200
     summary:     ROOT

And once we update, we don't have an obsolete changeset in the log anymore so
we don't show obsfate anymore, most users won't see obsfate often if they
don't have obsolete changeset often:

  @  changeset:   2:6f91013c5136
  |  tag:         tip
  |  parent:      0:4ef7b558f3ec
  |  user:        Boris Feld <[e-mail]>
  |  date:        Mon Oct 09 16:00:27 2017 +0200
  |  summary:     A
  |
  o  changeset:   0:feb4dd822b8c
     user:        Boris Feld <[e-mail]>
     date:        Tue Oct 09 16:00:00 2017 +0200
     summary:     ROOT

# discovery.py - protocol changeset discovery functions
#
# Copyright 2010 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 __future__ import absolute_import

import collections

from .i18n import _
from .node import (
    nullid,
    short,
)
from . import (
    error,
)

def findcommonincoming(repo, remote, heads=None, force=False):
    """Return a tuple (common, fetch, 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.
    "fetch" is a list of roots of the nodes that would be incoming, to be
      supplied to changegroupsubset.
    "heads" is either the supplied heads, or else the remote's heads.
    """

    knownnode = repo.changelog.hasnode
    search = []
    fetch = set()
    seen = set()
    seenbranch = set()
    base = set()

    if not heads:
        heads = remote.heads()

    if repo.changelog.tip() == nullid:
        base.add(nullid)
        if heads != [nullid]:
            return [nullid], [nullid], list(heads)
        return [nullid], [], heads

    # assume we're closer to the tip than the root
    # and start by examining the heads
    repo.ui.status(_("searching for changes\n"))

    unknown = []
    for h in heads:
        if not knownnode(h):
            unknown.append(h)
        else:
            base.add(h)

    if not unknown:
        return list(base), [], list(heads)

    req = set(unknown)
    reqcnt = 0

    # search through remote branches
    # a 'branch' here is a linear segment of history, with four parts:
    # head, root, first parent, second parent
    # (a branch always has two parents (or none) by definition)
    unknown = collections.deque(remote.branches(unknown))
    while unknown:
        r = []
        while unknown:
            n = unknown.popleft()
            if n[0] in seen:
                continue

            repo.ui.debug("examining %s:%s\n"
                          % (short(n[0]), short(n[1])))
            if n[0] == nullid: # found the end of the branch
                pass
            elif n in seenbranch:
                repo.ui.debug("branch already found\n")
                continue
            elif n[1] and knownnode(n[1]): # do we know the base?
                repo.ui.debug("found incomplete branch %s:%s\n"
                              % (short(n[0]), short(n[1])))
                search.append(n[0:2]) # schedule branch range for scanning
                seenbranch.add(n)
            else:
                if n[1] not in seen and n[1] not in fetch:
                    if knownnode(n[2]) and knownnode(n[3]):
                        repo.ui.debug("found new changeset %s\n" %
                                      short(n[1]))
                        fetch.add(n[1]) # earliest unknown
                    for p in n[2:4]:
                        if knownnode(p):
                            base.add(p) # latest known

                for p in n[2:4]:
                    if p not in req and not knownnode(p):
                        r.append(p)
                        req.add(p)
            seen.add(n[0])

        if r:
            reqcnt += 1
            repo.ui.progress(_('searching'), reqcnt, unit=_('queries'))
            repo.ui.debug("request %d: %s\n" %
                        (reqcnt, " ".join(map(short, r))))
            for p in xrange(0, len(r), 10):
                for b in remote.branches(r[p:p + 10]):
                    repo.ui.debug("received %s:%s\n" %
                                  (short(b[0]), short(b[1])))
                    unknown.append(b)

    # do binary search on the branches we found
    while search:
        newsearch = []
        reqcnt += 1
        repo.ui.progress(_('searching'), reqcnt, unit=_('queries'))
        for n, l in zip(search, remote.between(search)):
            l.append(n[1])
            p = n[0]
            f = 1
            for i in l:
                repo.ui.debug("narrowing %d:%d %s\n" % (f, len(l), short(i)))
                if knownnode(i):
                    if f <= 2:
                        repo.ui.debug("found new branch changeset %s\n" %
                                          short(p))
                        fetch.add(p)
                        base.add(i)
                    else:
                        repo.ui.debug("narrowed branch search to %s:%s\n"
                                      % (short(p), short(i)))
                        newsearch.append((p, i))
                    break
                p, f = i, f * 2
            search = newsearch

    # sanity check our fetch list
    for f in fetch:
        if knownnode(f):
            raise error.RepoError(_("already have changeset ")
                                  + short(f[:4]))

    base = list(base)
    if base == [nullid]:
        if force:
            repo.ui.warn(_("warning: repository is unrelated\n"))
        else:
            raise error.Abort(_("repository is unrelated"))

    repo.ui.debug("found new changesets starting at " +
                 " ".join([short(f) for f in fetch]) + "\n")

    repo.ui.progress(_('searching'), None)
    repo.ui.debug("%d total queries\n" % reqcnt)

    return base, list(fetch), heads