view mercurial/rewriteutil.py @ 44717:3dc6a70779f2

phabricator: add an option to fold several commits into one review (issue6244)

Now that all of the pieces are in place, alter the user facing command to allow
it.  This is the default behavior when using `arc`, but I much prefer the 1:1
approach, and I'm tempted to mark this advanced to limit its abuse.  I started
out calling this `--no-stack` like the feature request suggested, but I found it
less obvious (especially when writing the code), so I went with the `hg fold`
analogue.

This will populate the `Commits` tab in the web UI with the hash of each commit
folded into the review.  From experimentation, it seems to list them in the
order they are received from the extension instead of the actual parent/child
relationship.  The extension sends them in sorted order, thanks to
`templatefilters.json()`.  Since there's enough info there for them to put
things in the right order, JSON is unordered aside from lists (IIUC), and there
doesn't seem to be any harmful side effects, I guess we write this off as their
bug.  It is simple enough to workaround by putting a check for `util.sortdict`
into `templatefilters.json()`, and don't resort in that case.

There are a handful of restrictions that are documented in the code, which
somebody could probably fix if they're interested.  Notably, this requires the
(default) `--amend` option, because there's not an easy way to apply a local tag
across several commits.  This also doesn't do preflight checking to ensure that
all previous commits that were part of a single review are selected when
updating.  That seems expensive.  What happens is the excluded commit is dropped
from the review, but it keeps the Differential Revision line in the commit
message.  Not everything can be edited, so it doesn't seem worth making the code
even more complicated to handle this edge case.

There are a couple of "obsolete feature not enabled but X markers found!"
messages that appeared on Windows but not macOS.  I have no idea what's going on
here, but that's an unrelated issue, so I conditionalized those lines.

Differential Revision: https://phab.mercurial-scm.org/D8314

# 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)