view mercurial/rewriteutil.py @ 44335:e41a164db7a9

nodemap: track the maximum revision tracked in the nodemap

We need a simple way to detect when the on disk data contains less revision
than the index we read from disk. The docket file is meant for this, we just had
to start tracking that data.

We should also try to detect strip operation, but we will deal with this in
later changesets. Right now we are focusing on defining the API for index
supporting persistent nodemap.

Differential Revision: https://phab.mercurial-scm.org/D7888

# 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=b'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 = _(b"cannot %s null changeset") % action
        hint = _(b"no changeset checked out")
        raise error.Abort(msg, hint=hint)

    if len(repo[None].parents()) > 1:
        raise error.Abort(_(b"cannot %s while merging") % action)

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

    newunstable = disallowednewunstable(repo, revs)
    if newunstable:
        raise error.Abort(_(b"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(b"(%ld::) - %ld", revs, revs)