exchange: support transferring .hgtags fnodes mapping
On Mozilla's mozilla-beta repository .hgtags fnodes resolution takes
~18s from a clean cache on my machine. This means that the first time
a user runs `hg tags`, `hg log`, or any other command that displays or
accesses tags data, a ~18s pause will occur. There is no output during
this pause. This results in a poor user experience and perception
that Mercurial is slow.
The .hgtags changeset to filenode mapping is deterministic. This
patch takes advantage of that property by implementing support
for transferring .hgtags filenodes mappings in a dedicated bundle2
part. When a client advertising support for the "hgtagsfnodes"
capability requests a bundle, a mapping of changesets to .hgtags
filenodes will be sent to the client.
Only mappings of head changesets included in the bundle will be sent. The
transfer of this mapping effectively eliminates one time tags cache related
pauses after initial clone.
The mappings are sent as binary data. So, 40 bytes per pair of
SHA-1s. On the aforementioned mozilla-beta repository,
659 * 40 = 26,360 raw bytes of mappings are sent over the wire
(in addition to the bundle part headers). Assuming 18s to populate
the cache, we only need to transfer this extra data faster than
1.5 KB/s for overall clone + tags cache population time to be shorter.
Put into perspective, the mozilla-beta repository is ~1 GB in size.
So, this additional data constitutes <0.01% of the cloned data.
The marginal overhead for a multi-second performance win on clones
in my opinion justifies an on-by-default behavior.
"""strip changesets and their descendants from history
This extension allows you to strip changesets and all their descendants from the
repository. See the command help for details.
"""
from mercurial.i18n import _
from mercurial.node import nullid
from mercurial.lock import release
from mercurial import cmdutil, hg, scmutil, util
from mercurial import repair, bookmarks, merge
cmdtable = {}
command = cmdutil.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'internal' 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 = 'internal'
def checksubstate(repo, baserev=None):
'''return list of subrepos at a different revision than substate.
Abort if any subrepos have uncommitted changes.'''
inclsubs = []
wctx = repo[None]
if baserev:
bctx = repo[baserev]
else:
bctx = wctx.parents()[0]
for s in sorted(wctx.substate):
wctx.sub(s).bailifchanged(True)
if s not in bctx.substate or bctx.sub(s).dirty():
inclsubs.append(s)
return inclsubs
def checklocalchanges(repo, force=False, excsuffix=''):
cmdutil.checkunfinished(repo)
s = repo.status()
if not force:
if s.modified or s.added or s.removed or s.deleted:
_("local changes found") # i18n tool detection
raise util.Abort(_("local changes found" + excsuffix))
if checksubstate(repo):
_("local changed subrepos found") # i18n tool detection
raise util.Abort(_("local changed subrepos found" + excsuffix))
return s
def strip(ui, repo, revs, update=True, backup=True, force=None, bookmark=None):
wlock = lock = None
try:
wlock = repo.wlock()
lock = repo.lock()
if update:
checklocalchanges(repo, force=force)
urev, p2 = repo.changelog.parents(revs[0])
if (util.safehasattr(repo, 'mq') and
p2 != nullid
and p2 in [x.node for x in repo.mq.applied]):
urev = p2
hg.clean(repo, urev)
repo.dirstate.write()
repair.strip(ui, repo, revs, backup)
marks = repo._bookmarks
if bookmark:
if bookmark == repo._activebookmark:
bookmarks.deactivate(repo)
del marks[bookmark]
marks.write()
ui.write(_("bookmark '%s' deleted\n") % bookmark)
finally:
release(lock, wlock)
@command("strip",
[
('r', 'rev', [], _('strip specified revision (optional, '
'can specify revisions without this '
'option)'), _('REV')),
('f', 'force', None, _('force removal of changesets, discard '
'uncommitted changes (no backup)')),
('', 'no-backup', None, _('no backups')),
('', 'nobackup', None, _('no backups (DEPRECATED)')),
('n', '', None, _('ignored (DEPRECATED)')),
('k', 'keep', None, _("do not modify working directory during "
"strip")),
('B', 'bookmark', '', _("remove revs only reachable from given"
" bookmark"))],
_('hg strip [-k] [-f] [-n] [-B bookmark] [-r] REV...'))
def stripcmd(ui, repo, *revs, **opts):
"""strip changesets and all their descendants from the repository
The strip command removes the specified changesets and all their
descendants. If the working directory has uncommitted changes, the
operation is aborted unless the --force flag is supplied, in which
case changes will be discarded.
If a parent of the working directory is stripped, then the working
directory will automatically be updated to the most recent
available ancestor of the stripped parent after the operation
completes.
Any stripped changesets are stored in ``.hg/strip-backup`` as a
bundle (see :hg:`help bundle` and :hg:`help unbundle`). They can
be restored by running :hg:`unbundle .hg/strip-backup/BUNDLE`,
where BUNDLE is the bundle file created by the strip. Note that
the local revision numbers will in general be different after the
restore.
Use the --no-backup option to discard the backup bundle once the
operation completes.
Strip is not a history-rewriting operation and can be used on
changesets in the public phase. But if the stripped changesets have
been pushed to a remote repository you will likely pull them again.
Return 0 on success.
"""
backup = True
if opts.get('no_backup') or opts.get('nobackup'):
backup = False
cl = repo.changelog
revs = list(revs) + opts.get('rev')
revs = set(scmutil.revrange(repo, revs))
wlock = repo.wlock()
try:
if opts.get('bookmark'):
mark = opts.get('bookmark')
marks = repo._bookmarks
if mark not in marks:
raise util.Abort(_("bookmark '%s' not found") % mark)
# If the requested bookmark is not the only one pointing to a
# a revision we have to only delete the bookmark and not strip
# anything. revsets cannot detect that case.
uniquebm = True
for m, n in marks.iteritems():
if m != mark and n == repo[mark].node():
uniquebm = False
break
if uniquebm:
rsrevs = repo.revs("ancestors(bookmark(%s)) - "
"ancestors(head() and not bookmark(%s)) - "
"ancestors(bookmark() and not bookmark(%s))",
mark, mark, mark)
revs.update(set(rsrevs))
if not revs:
del marks[mark]
marks.write()
ui.write(_("bookmark '%s' deleted\n") % mark)
if not revs:
raise util.Abort(_('empty revision set'))
descendants = set(cl.descendants(revs))
strippedrevs = revs.union(descendants)
roots = revs.difference(descendants)
update = False
# if one of the wdir parent is stripped we'll need
# to update away to an earlier revision
for p in repo.dirstate.parents():
if p != nullid and cl.rev(p) in strippedrevs:
update = True
break
rootnodes = set(cl.node(r) for r in roots)
q = getattr(repo, 'mq', None)
if q is not None and q.applied:
# refresh queue state if we're about to strip
# applied patches
if cl.rev(repo.lookup('qtip')) in strippedrevs:
q.applieddirty = True
start = 0
end = len(q.applied)
for i, statusentry in enumerate(q.applied):
if statusentry.node in rootnodes:
# if one of the stripped roots is an applied
# patch, only part of the queue is stripped
start = i
break
del q.applied[start:end]
q.savedirty()
revs = sorted(rootnodes)
if update and opts.get('keep'):
urev, p2 = repo.changelog.parents(revs[0])
if (util.safehasattr(repo, 'mq') and p2 != nullid
and p2 in [x.node for x in repo.mq.applied]):
urev = p2
uctx = repo[urev]
# only reset the dirstate for files that would actually change
# between the working context and uctx
descendantrevs = repo.revs("%s::." % uctx.rev())
changedfiles = []
for rev in descendantrevs:
# blindly reset the files, regardless of what actually changed
changedfiles.extend(repo[rev].files())
# reset files that only changed in the dirstate too
dirstate = repo.dirstate
dirchanges = [f for f in dirstate if dirstate[f] != 'n']
changedfiles.extend(dirchanges)
repo.dirstate.rebuild(urev, uctx.manifest(), changedfiles)
repo.dirstate.write()
# clear resolve state
ms = merge.mergestate(repo)
ms.reset(repo['.'].node())
update = False
strip(ui, repo, revs, backup=backup, update=update,
force=opts.get('force'), bookmark=opts.get('bookmark'))
finally:
wlock.release()
return 0