comparison hgext/rebase.py @ 34005:5e83a8fe6bc4

rebase: initial support for multiple destinations

This patch defines `SRC` (a single source revision) and `ALLSRC` (all source
revisions) to be valid names in  `--dest` revset if `--src` or `--rev` is
used. So destination could be defined differently according to source
revisions. The names are capitalized to make it clear they are "dynamically
defined", distinguishable from normal revsets (Thanks Augie for the
suggestion).

This is useful, for example, `-r 'orphan()' -d 'calc-dest(SRC)'` to solve
instability, which seems to be a highly wanted feature.

The feature is not completed, namely if `-d` overlaps with `-r`, things
could go wrong. A later patch will handle that case.

The feature is also gated by `experimental.rebase.multidest` config option
which is default off.

Differential Revision: https://phab.mercurial-scm.org/D469

34004:af609bb3487f

    phases,
    registrar,
    repair,
    repoview,
    revset,
    scmutil,
    smartset,
    util,
)

    if ui.configbool('commands', 'rebase.requiredest') and not destf:
        raise error.Abort(_('you must specify a destination'),
                          hint=_('use: hg rebase -d REV'))

    if destf:
        dest = scmutil.revsingle(repo, destf)

    if revf:
        rebaseset = scmutil.revrange(repo, revf)
        if not rebaseset:
            ui.status(_('empty "rev" revision set - nothing to rebase\n'))

        base = scmutil.revrange(repo, [basef or '.'])
        if not base:
            ui.status(_('empty "base" revision set - '
                        "can't compute rebase set\n"))
            return None
        if not destf:
            dest = repo[_destrebase(repo, base, destspace=destspace)]
            destf = str(dest)

        roots = [] # selected children of branching points
        bpbase = {} # {branchingpoint: [origbase]}

    if not destf:
        dest = repo[_destrebase(repo, rebaseset, destspace=destspace)]
        destf = str(dest)

    # assign dest to each rev in rebaseset
    destrev = dest.rev()
    destmap = {r: destrev for r in rebaseset} # {srcrev: destrev}

    return destmap

def externalparent(repo, state, destancestors):
    """Return the revision that should be used as the second parent

    rev is what is being rebased. Return a list of two revs, which are the
    adjusted destinations for rev's p1 and p2, respectively. If a parent is
    nullrev, return dest without adjustment for it.

    For example, when doing rebase -r B+E -d F, rebase will first move B to B1,
    and E's destination will be adjusted from F to B1.

        B1 <- written during rebasing B
        |
        F <- original destination of B, E
        |

        | |
        | D <- prev, one parent of rev being checked
        | |
        | x <- skipped, ex. no successor or successor in (::dest)
        | |
        | C
        | |
        | B <- rebased as B1
        |/
        A

    Another example about merge changeset, rebase -r C+G+H -d K, rebase will
    first move C to C1, G to G1, and when it's checking H, the adjusted
    destinations will be [C1, G1].

34005:5e83a8fe6bc4

    phases,
    registrar,
    repair,
    repoview,
    revset,
    revsetlang,
    scmutil,
    smartset,
    util,
)

    if ui.configbool('commands', 'rebase.requiredest') and not destf:
        raise error.Abort(_('you must specify a destination'),
                          hint=_('use: hg rebase -d REV'))

    dest = None

    if revf:
        rebaseset = scmutil.revrange(repo, revf)
        if not rebaseset:
            ui.status(_('empty "rev" revision set - nothing to rebase\n'))

        base = scmutil.revrange(repo, [basef or '.'])
        if not base:
            ui.status(_('empty "base" revision set - '
                        "can't compute rebase set\n"))
            return None
        if destf:
            # --base does not support multiple destinations
            dest = scmutil.revsingle(repo, destf)
        else:
            dest = repo[_destrebase(repo, base, destspace=destspace)]
            destf = str(dest)

        roots = [] # selected children of branching points
        bpbase = {} # {branchingpoint: [origbase]}

    if not destf:
        dest = repo[_destrebase(repo, rebaseset, destspace=destspace)]
        destf = str(dest)

    allsrc = revsetlang.formatspec('%ld', rebaseset)
    alias = {'ALLSRC': allsrc}

    if dest is None:
        try:
            # fast path: try to resolve dest without SRC alias
            dest = scmutil.revsingle(repo, destf, localalias=alias)
        except error.RepoLookupError:
            if not ui.configbool('experimental', 'rebase.multidest'):
                raise
            # multi-dest path: resolve dest for each SRC separately
            destmap = {}
            for r in rebaseset:
                alias['SRC'] = revsetlang.formatspec('%d', r)
                # use repo.anyrevs instead of scmutil.revsingle because we
                # don't want to abort if destset is empty.
                destset = repo.anyrevs([destf], user=True, localalias=alias)
                size = len(destset)
                if size == 1:
                    destmap[r] = destset.first()
                elif size == 0:
                    ui.note(_('skipping %s - empty destination\n') % repo[r])
                else:
                    raise error.Abort(_('rebase destination for %s is not '
                                        'unique') % repo[r])

    if dest is not None:
        # single-dest case: assign dest to each rev in rebaseset
        destrev = dest.rev()
        destmap = {r: destrev for r in rebaseset} # {srcrev: destrev}

    if not destmap:
        ui.status(_('nothing to rebase - empty destination\n'))
        return None

    return destmap

def externalparent(repo, state, destancestors):
    """Return the revision that should be used as the second parent

    rev is what is being rebased. Return a list of two revs, which are the
    adjusted destinations for rev's p1 and p2, respectively. If a parent is
    nullrev, return dest without adjustment for it.

    For example, when doing rebasing B+E to F, C to G, rebase will first move B
    to B1, and E's destination will be adjusted from F to B1.

        B1 <- written during rebasing B
        |
        F <- original destination of B, E
        |

        | |
        | D <- prev, one parent of rev being checked
        | |
        | x <- skipped, ex. no successor or successor in (::dest)
        | |
        | C <- rebased as C', different destination
        | |
        | B <- rebased as B1     C'
        |/                       |
        A                        G <- destination of C, different

    Another example about merge changeset, rebase -r C+G+H -d K, rebase will
    first move C to C1, G to G1, and when it's checking H, the adjusted
    destinations will be [C1, G1].