absorb: preserve changesets which were already empty
Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty
changesets or drop them if they become empty. If there’s a changeset that’s
empty, it must be a deliberate choice of the user. At least it shouldn’t be
absorb’s responsibility to prune them. The fact that changesets that became
empty during absorb are pruned, is unaffected by this.
This case was found while writing patches which make it possible to configure
absorb and rebase to not drop empty changesets. Even without having such config
set, I think it’s valuable to preserve changesets which were already empty.
# dirstatenonnormalcheck.py - extension to check the consistency of the
# dirstate's non-normal map
#
# For most operations on dirstate, this extensions checks that the nonnormalset
# contains the right entries.
# It compares the nonnormal file to a nonnormalset built from the map of all
# the files in the dirstate to check that they contain the same files.
from __future__ import absolute_import
from mercurial import (
dirstate,
extensions,
)
def nonnormalentries(dmap):
"""Compute nonnormal entries from dirstate's dmap"""
res = set()
for f, e in dmap.iteritems():
if e[0] != b'n' or e[3] == -1:
res.add(f)
return res
def checkconsistency(ui, orig, dmap, _nonnormalset, label):
"""Compute nonnormalset from dmap, check that it matches _nonnormalset"""
nonnormalcomputedmap = nonnormalentries(dmap)
if _nonnormalset != nonnormalcomputedmap:
ui.develwarn(b"%s call to %s\n" % (label, orig), config=b'dirstate')
ui.develwarn(b"inconsistency in nonnormalset\n", config=b'dirstate')
ui.develwarn(b"[nonnormalset] %s\n" % _nonnormalset, config=b'dirstate')
ui.develwarn(b"[map] %s\n" % nonnormalcomputedmap, config=b'dirstate')
def _checkdirstate(orig, self, arg):
"""Check nonnormal set consistency before and after the call to orig"""
checkconsistency(
self._ui, orig, self._map, self._map.nonnormalset, b"before"
)
r = orig(self, arg)
checkconsistency(
self._ui, orig, self._map, self._map.nonnormalset, b"after"
)
return r
def extsetup(ui):
"""Wrap functions modifying dirstate to check nonnormalset consistency"""
dirstatecl = dirstate.dirstate
devel = ui.configbool(b'devel', b'all-warnings')
paranoid = ui.configbool(b'experimental', b'nonnormalparanoidcheck')
if devel:
extensions.wrapfunction(dirstatecl, '_writedirstate', _checkdirstate)
if paranoid:
# We don't do all these checks when paranoid is disable as it would
# make the extension run very slowly on large repos
extensions.wrapfunction(dirstatecl, 'normallookup', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'otherparent', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'normal', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'write', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'add', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'remove', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'merge', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'drop', _checkdirstate)