hgext/uncommit.py

subrepo: handle 'C:' style paths on the command line (issue5770)

If you think 'C:' and 'C:\' are equivalent paths, see the inline comment before
proceeding.

The problem here was that several commands that take a URL argument (incoming,
outgoing, pull, and push) will use that value to set 'repo._subtoppath' on the
repository object after command specific manipulation of it, but before
converting it to an absolute path.  When an operation is performed on a relative
subrepo, subrepo._abssource() will posixpath.join() this value with the relative
subrepo path.  That adds a '/' after the drive letter, changing how it is
evaluated by abspath()/realpath() in vfsmod.vfs(..., realpath=True) as the
subrepo is instantiated.

I initially tried sanitizing the path in url.localpath(), because url.isabs()
only checks that it starts with a drive letter.  By the sample behavior, this is
clearly not an absolute path.  (Though the comment in isabs() is weasely- this
style path can't be joined either.)  But not everything funnels through there,
and it required explicitly calling localpath() in hg.parseurl() and assigning to
url.path to fix.  But then tests failed with urls like 'a#0'.

Next up was sanitizing the path in the url constructor.  That caused doctest
failures, because there are drive letter tests, so those got expanded in system
specific ways.  Yuya correctly pointed out that util.url is a parser, and
shouldn't be substituting the path too.

Rather than fixing every command call site, just convert it in the common
subrepo location.  I don't see any sanitizing on the path config options, so I
fixed those too.  Note that while the behavior is fixed here, there are still
places where 'comparing with C:' gets printed out, and that's not great for
debugging purposes.  (Specifically I saw it in `hg incoming -B C:`, without
subrepos.)  While clone will write out an absolute default path, I wonder what
would happen if a user edited that path to be 'C:'.  (I don't think supporting
relative paths in .hgrc is a sane thing to do, but while we're poking holes in
things...)

Since this is such an oddball case, it still leaks through in places, and there
seems to be a lot of duplicate url parsing, maybe the url parsing should be
moved to dispatch, and provide the command with a url object?  Then we could
convert this to an absolute path once, and not have to worry about it in the
rest of the code.

I also checked '--cwd C:' on the command line, and it was previously working
because os.chdir() will DTRT.

Finally, one other note from the url.localpath() experimenting.  I don't see any
cases where 'self._hostport' can hold a drive letter.  So I'm wondering if that
is wrong/old code.

# 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, allowempty):
    """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 files and not allowempty:
        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())
    # phase handling
    commitphase = ctx.phase()
    overrides = {('phases', 'new-commit'): commitphase}
    with repo.ui.configoverride(overrides, 'uncommit'):
        newid = repo.commitctx(new)
    return newid

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]...'))
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.
    """
    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)
            newid = _commitfiltered(repo, old, match, opts.get('keep'))
            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')

            with repo.dirstate.parentchange():
                repo.dirstate.setparents(newid, node.nullid)
                s = repo.status(old.p1(), 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', [])
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)
        # phase handling
        commitphase = curctx.phase()
        overrides = {('phases', 'new-commit'): commitphase}
        with repo.ui.configoverride(overrides, 'uncommit'):
            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')