view mercurial/rewriteutil.py @ 39672:a1942015c10e

changegroup: add functionality to skip adding changelog data to changegroup

In narrow extension, when we have a non-ellipses narrow working copy and we
extend it, we pull all the changelog data again and the client tries to reapply
all that changelog data.

While downloading millions of changeset data is still not very expensive but
applying them on the client side is very expensive and takes ~10 minutes. These
10 minutes are added to every  `hg tracked --addinclude <>` call and extending
a narrow copy becomes very slow.

This patch adds a new changelog argument to cgpacker.generate() fn. If the
changelog argument is set to False, we won't yield the changelog data. We still
have to iterate over the deltas returned by _generatechangelog() because that's
a generator and builds the data for clstate variable which is required for
calculating manifests and filelogs.

Differential Revision: https://phab.mercurial-scm.org/D4638

# rewriteutil.py - utility functions for rewriting changesets
#
# Copyright 2017 Octobus <[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

from .i18n import _

from . import (
    error,
    node,
    obsolete,
    revset,
)

def precheck(repo, revs, action='rewrite'):
    """check if revs can be rewritten
    action is used to control the error message.

    Make sure this function is called after taking the lock.
    """
    if node.nullrev in revs:
        msg = _("cannot %s null changeset") % (action)
        hint = _("no changeset checked out")
        raise error.Abort(msg, hint=hint)

    publicrevs = repo.revs('%ld and public()', revs)
    if len(repo[None].parents()) > 1:
        raise error.Abort(_("cannot %s while merging") % action)

    if publicrevs:
        msg = _("cannot %s public changesets") % (action)
        hint = _("see 'hg help phases' for details")
        raise error.Abort(msg, hint=hint)

    newunstable = disallowednewunstable(repo, revs)
    if newunstable:
        raise error.Abort(_("cannot %s changeset with children") % action)

def disallowednewunstable(repo, revs):
    """Checks whether editing the revs will create new unstable changesets and
    are we allowed to create them.

    To allow new unstable changesets, set the config:
        `experimental.evolution.allowunstable=True`
    """
    allowunstable = obsolete.isenabled(repo, obsolete.allowunstableopt)
    if allowunstable:
        return revset.baseset()
    return repo.revs("(%ld::) - %ld", revs, revs)