##// END OF EJS Templates
rebase: do not invent successor to skipped changeset...
rebase: do not invent successor to skipped changeset When rebase results in an empty a changeset it is "skipped" and no related changeset is created at all. When we added obsolescence support to rebase (in fc2a6114f0a0) it seemed a good idea to use its parent successor as the successors for such dropped changesets. (see old version of the altered test). This option was chosen because it seems a good way to hint about were the dropped changeset "intended" to be. Such hint would have been used by automatic evolution mechanism to rebase potential unstable children. However, field testing of this version are not conclusive. It very often leads to the creation of (totally unfounded) evolution divergence. This changeset changes this behavior and mark skipped changesets as pruned (obsolete without successors). This prevents the issue and seems semantically better probably a win for obsolescence reading tool. See example bellow for details: User Babar has five changesets of interest: - O, its current base of development. - U, the new upstream - A and C, some development changesets - B another development changeset independent from A O - A - B - C \ U Babar decides that B is more critical than the A and C and rebase it first $ hg rebase --rev B --dest U B is now obsolete (in lower case bellow). Rebase result, B', is its successors.(note, C is unstable) O - A - b - C \ U - B' Babar is now done with B', and want to rebase the rest of its history: $ hg rebase --source A --dest B' hg rebase process A, B and C. B is skipped as all its changes are already contained in B'. O - U - B' - A' - C' Babar have the expected result graph wise, obsolescence marker are as follow: B -> B' (from first rebase) A -> A' (from second rebase) C -> C' (from second rebase) B -> ?? (from second rebase) Before this changeset, the last marker is `B -> A'`. This cause two issues: - This is semantically wrong. B have nothing to do with A' - B has now two successors sets: (B',) and (A',). We detect a divergent rewriting. The B' and A' are reported as "divergent" to Babar, confusion ensues. In addition such divergent situation (divergent changeset are children to each other) is tricky to solve. With this changeset the last marker is `B -> ΓΈ`: - This is semantically better. - B has a single successors set (B',) This scenario is added to the tests suite.

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treediscovery.py
150 lines | 5.1 KiB | text/x-python | PythonLexer
# discovery.py - protocol changeset discovery functions
#
# Copyright 2010 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from node import nullid, short
from i18n import _
import util, error
def findcommonincoming(repo, remote, heads=None, force=False):
"""Return a tuple (common, fetch, heads) used to identify the common
subset of nodes between repo and remote.
"common" is a list of (at least) the heads of the common subset.
"fetch" is a list of roots of the nodes that would be incoming, to be
supplied to changegroupsubset.
"heads" is either the supplied heads, or else the remote's heads.
"""
m = repo.changelog.nodemap
search = []
fetch = set()
seen = set()
seenbranch = set()
base = set()
if not heads:
heads = remote.heads()
if repo.changelog.tip() == nullid:
base.add(nullid)
if heads != [nullid]:
return [nullid], [nullid], list(heads)
return [nullid], [], heads
# assume we're closer to the tip than the root
# and start by examining the heads
repo.ui.status(_("searching for changes\n"))
unknown = []
for h in heads:
if h not in m:
unknown.append(h)
else:
base.add(h)
if not unknown:
return list(base), [], list(heads)
req = set(unknown)
reqcnt = 0
# search through remote branches
# a 'branch' here is a linear segment of history, with four parts:
# head, root, first parent, second parent
# (a branch always has two parents (or none) by definition)
unknown = util.deque(remote.branches(unknown))
while unknown:
r = []
while unknown:
n = unknown.popleft()
if n[0] in seen:
continue
repo.ui.debug("examining %s:%s\n"
% (short(n[0]), short(n[1])))
if n[0] == nullid: # found the end of the branch
pass
elif n in seenbranch:
repo.ui.debug("branch already found\n")
continue
elif n[1] and n[1] in m: # do we know the base?
repo.ui.debug("found incomplete branch %s:%s\n"
% (short(n[0]), short(n[1])))
search.append(n[0:2]) # schedule branch range for scanning
seenbranch.add(n)
else:
if n[1] not in seen and n[1] not in fetch:
if n[2] in m and n[3] in m:
repo.ui.debug("found new changeset %s\n" %
short(n[1]))
fetch.add(n[1]) # earliest unknown
for p in n[2:4]:
if p in m:
base.add(p) # latest known
for p in n[2:4]:
if p not in req and p not in m:
r.append(p)
req.add(p)
seen.add(n[0])
if r:
reqcnt += 1
repo.ui.progress(_('searching'), reqcnt, unit=_('queries'))
repo.ui.debug("request %d: %s\n" %
(reqcnt, " ".join(map(short, r))))
for p in xrange(0, len(r), 10):
for b in remote.branches(r[p:p + 10]):
repo.ui.debug("received %s:%s\n" %
(short(b[0]), short(b[1])))
unknown.append(b)
# do binary search on the branches we found
while search:
newsearch = []
reqcnt += 1
repo.ui.progress(_('searching'), reqcnt, unit=_('queries'))
for n, l in zip(search, remote.between(search)):
l.append(n[1])
p = n[0]
f = 1
for i in l:
repo.ui.debug("narrowing %d:%d %s\n" % (f, len(l), short(i)))
if i in m:
if f <= 2:
repo.ui.debug("found new branch changeset %s\n" %
short(p))
fetch.add(p)
base.add(i)
else:
repo.ui.debug("narrowed branch search to %s:%s\n"
% (short(p), short(i)))
newsearch.append((p, i))
break
p, f = i, f * 2
search = newsearch
# sanity check our fetch list
for f in fetch:
if f in m:
raise error.RepoError(_("already have changeset ")
+ short(f[:4]))
base = list(base)
if base == [nullid]:
if force:
repo.ui.warn(_("warning: repository is unrelated\n"))
else:
raise util.Abort(_("repository is unrelated"))
repo.ui.debug("found new changesets starting at " +
" ".join([short(f) for f in fetch]) + "\n")
repo.ui.progress(_('searching'), None)
repo.ui.debug("%d total queries\n" % reqcnt)
return base, list(fetch), heads