mercurial/stack.py

templatekw: make negrev return empty for wdir() and nullrev

I considered just returning the same output that {rev} returns here,
but {rev} also returns essentially gibberish: either an INT_MAX-kind
of variable for wdir() or -1 for null. Since these are numbers that
are intended to be used for calculations, and since the numbers for
wdir() and -1 are not really very helpful for calculation (and worse,
when used as a revision number -1 is equal to unhidden tip), I figured
the most reasonable thing to do here is to just return nothing for
negrev.

This could potentially break scripts that are expecting to parse a
nonempty integer out of a {negrev}, but that seems like a very remote
concern at this juncture.

# stack.py - Mercurial functions for stack definition
#
#  Copyright Matt Mackall <[e-mail]> and other
#
# 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 . import (
    revsetlang,
    scmutil,
)

def getstack(repo, rev=None):
    """return a sorted smartrev of the stack containing either rev if it is
    not None or the current working directory parent.

    The stack will always contain all drafts changesets which are ancestors to
    the revision and are not merges.
    """
    if rev is None:
        rev = '.'

    revspec = 'reverse(only(%s) and not public() and not ::merge())'
    revset = revsetlang.formatspec(revspec, rev)
    revisions = scmutil.revrange(repo, [revset])
    revisions.sort()
    return revisions