view mercurial/rewriteutil.py @ 45468:09edbff6ae8d

merge: store ACTION_KEEP_ABSENT when we are keeping the file absent locally

If a file is not present on the local side, and it's unchanged between other
merge parent and ancestor, we don't use any action, neither we had a if-else
branch for that condition. This leads to bid-merge missing that there is a
such action possible which can be performed.

As test changes demonstrate, we now choose the locally deleted side instead
of choosing the remote one consistently. This is also wrong behavior which is
resulted because of missing possible action. It will be fixed in next patch.

This whole logic is not acurrate as we should prompt user on what to do
when this kind of criss-cross merge is in play.

Differential Revision: https://phab.mercurial-scm.org/D8940

# 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

import re

from .i18n import _

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


NODE_RE = re.compile(br'\b[0-9a-f]{6,64}\b')


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)


def skip_empty_successor(ui, command):
    empty_successor = ui.config(b'rewrite', b'empty-successor')
    if empty_successor == b'skip':
        return True
    elif empty_successor == b'keep':
        return False
    else:
        raise error.ConfigError(
            _(
                b"%s doesn't know how to handle config "
                b"rewrite.empty-successor=%s (only 'skip' and 'keep' are "
                b"supported)"
            )
            % (command, empty_successor)
        )


def update_hash_refs(repo, commitmsg, pending=None):
    """Replace all obsolete commit hashes in the message with the current hash.

    If the obsolete commit was split or is divergent, the hash is not replaced
    as there's no way to know which successor to choose.

    For commands that update a series of commits in the current transaction, the
    new obsolete markers can be considered by setting ``pending`` to a mapping
    of ``pending[oldnode] = [successor_node1, successor_node2,..]``.
    """
    if not pending:
        pending = {}
    cache = {}
    hashes = re.findall(NODE_RE, commitmsg)
    unfi = repo.unfiltered()
    for h in hashes:
        fullnode = scmutil.resolvehexnodeidprefix(unfi, h)
        if fullnode is None:
            continue
        ctx = unfi[fullnode]
        if not ctx.obsolete():
            successors = pending.get(fullnode)
            if successors is None:
                continue
            # obsutil.successorssets() returns a list of list of nodes
            successors = [successors]
        else:
            successors = obsutil.successorssets(repo, ctx.node(), cache=cache)

        # We can't make any assumptions about how to update the hash if the
        # cset in question was split or diverged.
        if len(successors) == 1 and len(successors[0]) == 1:
            newhash = node.hex(successors[0][0])
            commitmsg = commitmsg.replace(h, newhash[: len(h)])
        else:
            repo.ui.note(
                _(
                    b'The stale commit message reference to %s could '
                    b'not be updated\n'
                )
                % h
            )

    return commitmsg