view hgext3rd/topic/server.py @ 5601:3946ee4ee3ae

topic: add a `exp….topic.linear-merge` option to allow some oedipus

If this option is set to `from-branch`, a user can call `hg merge some-topic`
from a bare branch even if `some-topic` is a direct descendant of the current
working copy parents. This was previously denied if the changesets was on the
same branch, since the result would be an "oedipus merge".

Some user have been requesting this, and this type of merge is one of Gitlab
standard way of merging a "Merge Request". That new option will unlock issue
`heptapod#200` and make this mode available for those who wants it.

# topic/server.py - server specific behavior with topic
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from mercurial import (
    extensions,
    repoview,
    wireprototypes,
    wireprotov1peer,
    wireprotov1server,
)

try:
    from mercurial.utils import (
        repoviewutil,
    )
    repoviewutil.subsettable
except (AttributeError, ImportError):
    # hg <= 4.9 (caebe5e7f4bd)
    from mercurial import branchmap as repoviewutil

from . import (
    common,
    constants,
)

### Visibility restriction
#
# Serving draft changesets with topics to clients without topic extension can
# confuse them, because they won't see the topic label and will consider them
# normal anonymous heads. Instead we have the option to not serve changesets
# with topics to clients without topic support.
#
# To achieve this, we alter the behavior of the standard `heads` commands and
# introduce a new `heads` command that only clients with topic will know about.

# compat version of the wireprotocommand decorator, taken from evolve compat

FILTERNAME = b'served-no-topic'

def computeunservedtopic(repo, visibilityexceptions=None):
    assert not repo.changelog.filteredrevs
    filteredrevs = repoview.filtertable[b'served'](repo, visibilityexceptions).copy()
    mutable = repoview.filtertable[b'immutable'](repo, visibilityexceptions)
    consider = mutable - filteredrevs
    cl = repo.changelog
    extrafiltered = set()
    for r in consider:
        if cl.changelogrevision(r).extra.get(constants.extrakey, b''):
            extrafiltered.add(r)
    if extrafiltered:
        extrafiltered = set(repo.revs('%ld::%ld', extrafiltered, consider))
        filteredrevs = frozenset(filteredrevs | extrafiltered)
    return filteredrevs

def wrapheads(orig, repo, proto):
    """wrap head to hide topic^W draft changeset to old client"""
    hidetopics = repo.ui.configbool(b'experimental', b'topic.server-gate-topic-changesets')
    if common.hastopicext(repo) and hidetopics:
        h = repo.filtered(FILTERNAME).heads()
        return wireprototypes.bytesresponse(wireprototypes.encodelist(h) + b'\n')
    return orig(repo, proto)

def topicheads(repo, proto):
    """Same as the normal wireprotocol command, but accessing with a different end point."""
    h = repo.heads()
    return wireprototypes.bytesresponse(wireprototypes.encodelist(h) + b'\n')

def wireprotocaps(orig, repo, proto):
    """advertise the new topic specific `head` command for client with topic"""
    caps = orig(repo, proto)
    if common.hastopicext(repo) and repo.peer().capable(b'topics'):
        caps.append(b'_exttopics_heads')
    return caps

def setupserver(ui):
    extensions.wrapfunction(wireprotov1server, 'heads', wrapheads)
    wireprotov1server.commands.pop(b'heads')
    wireprotov1server.wireprotocommand(b'heads', permission=b'pull')(wireprotov1server.heads)
    wireprotov1server.wireprotocommand(b'_exttopics_heads', permission=b'pull')(topicheads)
    extensions.wrapfunction(wireprotov1server, '_capabilities', wireprotocaps)

    class topicpeerexecutor(wireprotov1peer.peerexecutor):

        def callcommand(self, command, args):
            if command == b'heads':
                if self._peer.capable(b'_exttopics_heads'):
                    command = b'_exttopics_heads'
                    if getattr(self._peer, '_exttopics_heads', None) is None:
                        self._peer._exttopics_heads = self._peer.heads
            s = super(topicpeerexecutor, self)
            return s.callcommand(command, args)

    wireprotov1peer.peerexecutor = topicpeerexecutor

    if FILTERNAME not in repoview.filtertable:
        repoview.filtertable[FILTERNAME] = computeunservedtopic
        repoviewutil.subsettable[FILTERNAME] = b'immutable'
        repoviewutil.subsettable[b'served'] = FILTERNAME