hgext/uncommit.py

wireprotov2: send linknodes to emitfilerevisions()

Previously, linknodes were calculated within emitfilerevisions() by
using filectx.introrev(), which would always use the linkrev/linknode
as recorded by storage. This is wrong for cases where the receiver
doesn't have the changeset the linknode refers to.

This commit changes the logic for linknode emission so the mapping
of filenode to linknode is computed by the caller and passed into
emitfilerevisions().

As part of the change, linknodes for "filesdata" in the
haveparents=False case are now correct: the existing code performed a
manifest walk and it was trivial to plug in the correct linknode.

However, behavior for the haveparents=True case is still wrong
because it relies on filtering linkrevs against the outgoing set in
order to determine what to send. This will be fixed in a subsequent
commit.

The change test test-wireproto-exchangev2-shallow.t is a bit wonky.
The test repo has 6 revisions. The changed test is performing a shallow
clone with depth=1. So, only file data for revision 5 is present
locally. So, the new behavior of associating the linknode with
revision 5 for every file revision seems correct. Of course, when
backfilling old revisions, we'll want to update the linknode. But
this problem requires wire protocol support and we'll cross that
bridge later.

Differential Revision: https://phab.mercurial-scm.org/D5405

# uncommit - undo the actions of a commit
#
# Copyright 2011 Peter Arrenbrecht <[e-mail]>
#                Logilab SA        <[e-mail]>
#                Pierre-Yves David <[e-mail]>
#                Patrick Mezard <[e-mail]>
# Copyright 2016 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""uncommit part or all of a local changeset (EXPERIMENTAL)

This command undoes the effect of a local commit, returning the affected
files to their uncommitted state. This means that files modified, added or
removed in the changeset will be left unchanged, and so will remain modified,
added and removed in the working directory.
"""

from __future__ import absolute_import

from mercurial.i18n import _

from mercurial import (
    cmdutil,
    commands,
    context,
    copies,
    error,
    node,
    obsutil,
    pycompat,
    registrar,
    rewriteutil,
    scmutil,
)

cmdtable = {}
command = registrar.command(cmdtable)

configtable = {}
configitem = registrar.configitem(configtable)

configitem('experimental', 'uncommitondirtywdir',
    default=False,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

def _commitfiltered(repo, ctx, match, keepcommit):
    """Recommit ctx with changed files not in match. Return the new
    node identifier, or None if nothing changed.
    """
    base = ctx.p1()
    # ctx
    initialfiles = set(ctx.files())
    exclude = set(f for f in initialfiles if match(f))

    # No files matched commit, so nothing excluded
    if not exclude:
        return None

    files = (initialfiles - exclude)
    # return the p1 so that we don't create an obsmarker later
    if not keepcommit:
        return ctx.parents()[0].node()

    # Filter copies
    copied = copies.pathcopies(base, ctx)
    copied = dict((dst, src) for dst, src in copied.iteritems()
                  if dst in files)
    def filectxfn(repo, memctx, path, contentctx=ctx, redirect=()):
        if path not in contentctx:
            return None
        fctx = contentctx[path]
        mctx = context.memfilectx(repo, memctx, fctx.path(), fctx.data(),
                                  fctx.islink(),
                                  fctx.isexec(),
                                  copied=copied.get(path))
        return mctx

    new = context.memctx(repo,
                         parents=[base.node(), node.nullid],
                         text=ctx.description(),
                         files=files,
                         filectxfn=filectxfn,
                         user=ctx.user(),
                         date=ctx.date(),
                         extra=ctx.extra())
    return repo.commitctx(new)

def _fixdirstate(repo, oldctx, newctx, status):
    """ fix the dirstate after switching the working directory from oldctx to
    newctx which can be result of either unamend or uncommit.
    """
    ds = repo.dirstate
    copies = dict(ds.copies())
    s = status
    for f in s.modified:
        if ds[f] == 'r':
            # modified + removed -> removed
            continue
        ds.normallookup(f)

    for f in s.added:
        if ds[f] == 'r':
            # added + removed -> unknown
            ds.drop(f)
        elif ds[f] != 'a':
            ds.add(f)

    for f in s.removed:
        if ds[f] == 'a':
            # removed + added -> normal
            ds.normallookup(f)
        elif ds[f] != 'r':
            ds.remove(f)

    # Merge old parent and old working dir copies
    oldcopies = {}
    for f in (s.modified + s.added):
        src = oldctx[f].renamed()
        if src:
            oldcopies[f] = src[0]
    oldcopies.update(copies)
    copies = dict((dst, oldcopies.get(src, src))
                  for dst, src in oldcopies.iteritems())
    # Adjust the dirstate copies
    for dst, src in copies.iteritems():
        if (src not in newctx or dst in newctx or ds[dst] != 'a'):
            src = None
        ds.copy(src, dst)

@command('uncommit',
    [('', 'keep', False, _('allow an empty commit after uncommiting')),
    ] + commands.walkopts,
    _('[OPTION]... [FILE]...'),
    helpcategory=command.CATEGORY_CHANGE_MANAGEMENT)
def uncommit(ui, repo, *pats, **opts):
    """uncommit part or all of a local changeset

    This command undoes the effect of a local commit, returning the affected
    files to their uncommitted state. This means that files modified or
    deleted in the changeset will be left unchanged, and so will remain
    modified in the working directory.

    If no files are specified, the commit will be pruned, unless --keep is
    given.
    """
    opts = pycompat.byteskwargs(opts)

    with repo.wlock(), repo.lock():

        if not pats and not repo.ui.configbool('experimental',
                                               'uncommitondirtywdir'):
            cmdutil.bailifchanged(repo)
        old = repo['.']
        rewriteutil.precheck(repo, [old.rev()], 'uncommit')
        if len(old.parents()) > 1:
            raise error.Abort(_("cannot uncommit merge changeset"))

        with repo.transaction('uncommit'):
            match = scmutil.match(old, pats, opts)
            keepcommit = opts.get('keep') or pats
            newid = _commitfiltered(repo, old, match, keepcommit)
            if newid is None:
                ui.status(_("nothing to uncommit\n"))
                return 1

            mapping = {}
            if newid != old.p1().node():
                # Move local changes on filtered changeset
                mapping[old.node()] = (newid,)
            else:
                # Fully removed the old commit
                mapping[old.node()] = ()

            scmutil.cleanupnodes(repo, mapping, 'uncommit', fixphase=True)

            with repo.dirstate.parentchange():
                repo.dirstate.setparents(newid, node.nullid)
                s = old.p1().status(old, match=match)
                _fixdirstate(repo, old, repo[newid], s)

def predecessormarkers(ctx):
    """yields the obsolete markers marking the given changeset as a successor"""
    for data in ctx.repo().obsstore.predecessors.get(ctx.node(), ()):
        yield obsutil.marker(ctx.repo(), data)

@command('unamend', [], helpcategory=command.CATEGORY_CHANGE_MANAGEMENT,
         helpbasic=True)
def unamend(ui, repo, **opts):
    """undo the most recent amend operation on a current changeset

    This command will roll back to the previous version of a changeset,
    leaving working directory in state in which it was before running
    `hg amend` (e.g. files modified as part of an amend will be
    marked as modified `hg status`)
    """

    unfi = repo.unfiltered()
    with repo.wlock(), repo.lock(), repo.transaction('unamend'):

        # identify the commit from which to unamend
        curctx = repo['.']

        rewriteutil.precheck(repo, [curctx.rev()], 'unamend')

        # identify the commit to which to unamend
        markers = list(predecessormarkers(curctx))
        if len(markers) != 1:
            e = _("changeset must have one predecessor, found %i predecessors")
            raise error.Abort(e % len(markers))

        prednode = markers[0].prednode()
        predctx = unfi[prednode]

        # add an extra so that we get a new hash
        # note: allowing unamend to undo an unamend is an intentional feature
        extras = predctx.extra()
        extras['unamend_source'] = curctx.hex()

        def filectxfn(repo, ctx_, path):
            try:
                return predctx.filectx(path)
            except KeyError:
                return None

        # Make a new commit same as predctx
        newctx = context.memctx(repo,
                                parents=(predctx.p1(), predctx.p2()),
                                text=predctx.description(),
                                files=predctx.files(),
                                filectxfn=filectxfn,
                                user=predctx.user(),
                                date=predctx.date(),
                                extra=extras)
        newprednode = repo.commitctx(newctx)
        newpredctx = repo[newprednode]
        dirstate = repo.dirstate

        with dirstate.parentchange():
            dirstate.setparents(newprednode, node.nullid)
            s = repo.status(predctx, curctx)
            _fixdirstate(repo, curctx, newpredctx, s)

        mapping = {curctx.node(): (newprednode,)}
        scmutil.cleanupnodes(repo, mapping, 'unamend', fixphase=True)