mercurial/verify.py

rebase: allow collapsing branches in place (issue3111)

We allow rebase plus collapse, but not collapse only? I imagine people would
rebase first then collapse once they are sure the rebase is correct and it is
the right time to finish it.

I was reluctant to submit this patch for reasons detailed below, but it
improves rebase --collapse usefulness so much it is worth the ugliness.

The fix is ugly because we should be fixing the collapse code path rather than
the merge. Collapsing by merging changesets repeatedly is inefficient compared
to what commit --amend does: commitctx(), update, strip. The problem with the
latter is, to generate the synthetic changeset, copy records are gathered with
copies.pathcopies(). copies.pathcopies() is still implemented with merging in
mind and discards information like file replaced by the copy of another,
criss-cross copies and so forth. I believe this information should not be lost,
even if we decide not to interpret it fully later, at merge time.

The second issue with improving rebase --collapse is the option should not be
there to begin with. Rebasing and collapsing are orthogonal and a dedicated
command would probably enable a better, simpler ui. We should avoid advertizing
rebase --collapse, but with this fix it becomes the best shipped solution to
collapse changesets.

And for the record, available techniques are:
- revert + commit + strip: lose copies
- mq/qfold: repeated patching() (mostly correct, fragile)
- rebase: repeated merges (mostly correct, fragile)
- collapse: revert + tag rewriting wizardry, lose copies
- histedit: repeated patching() (mostly correct, fragile)
- amend: copies.pathcopies() + commitctx() + update + strip

# verify.py - repository integrity checking for Mercurial
#
# Copyright 2006, 2007 Matt Mackall <[e-mail]>
#
# 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 os
import revlog, util, error

def verify(repo):
    lock = repo.lock()
    try:
        return _verify(repo)
    finally:
        lock.release()

def _verify(repo):
    mflinkrevs = {}
    filelinkrevs = {}
    filenodes = {}
    revisions = 0
    badrevs = set()
    errors = [0]
    warnings = [0]
    ui = repo.ui
    cl = repo.changelog
    mf = repo.manifest
    lrugetctx = util.lrucachefunc(repo.changectx)

    if not repo.cancopy():
        raise util.Abort(_("cannot verify bundle or remote repos"))

    def err(linkrev, msg, filename=None):
        if linkrev is not None:
            badrevs.add(linkrev)
        else:
            linkrev = '?'
        msg = "%s: %s" % (linkrev, msg)
        if filename:
            msg = "%s@%s" % (filename, msg)
        ui.warn(" " + msg + "\n")
        errors[0] += 1

    def exc(linkrev, msg, inst, filename=None):
        if isinstance(inst, KeyboardInterrupt):
            ui.warn(_("interrupted"))
            raise
        if not str(inst):
            inst = repr(inst)
        err(linkrev, "%s: %s" % (msg, inst), filename)

    def warn(msg):
        ui.warn(msg + "\n")
        warnings[0] += 1

    def checklog(obj, name, linkrev):
        if not len(obj) and (havecl or havemf):
            err(linkrev, _("empty or missing %s") % name)
            return

        d = obj.checksize()
        if d[0]:
            err(None, _("data length off by %d bytes") % d[0], name)
        if d[1]:
            err(None, _("index contains %d extra bytes") % d[1], name)

        if obj.version != revlog.REVLOGV0:
            if not revlogv1:
                warn(_("warning: `%s' uses revlog format 1") % name)
        elif revlogv1:
            warn(_("warning: `%s' uses revlog format 0") % name)

    def checkentry(obj, i, node, seen, linkrevs, f):
        lr = obj.linkrev(obj.rev(node))
        if lr < 0 or (havecl and lr not in linkrevs):
            if lr < 0 or lr >= len(cl):
                msg = _("rev %d points to nonexistent changeset %d")
            else:
                msg = _("rev %d points to unexpected changeset %d")
            err(None, msg % (i, lr), f)
            if linkrevs:
                if f and len(linkrevs) > 1:
                    try:
                        # attempt to filter down to real linkrevs
                        linkrevs = [l for l in linkrevs
                                    if lrugetctx(l)[f].filenode() == node]
                    except Exception:
                        pass
                warn(_(" (expected %s)") % " ".join(map(str, linkrevs)))
            lr = None # can't be trusted

        try:
            p1, p2 = obj.parents(node)
            if p1 not in seen and p1 != nullid:
                err(lr, _("unknown parent 1 %s of %s") %
                    (short(p1), short(n)), f)
            if p2 not in seen and p2 != nullid:
                err(lr, _("unknown parent 2 %s of %s") %
                    (short(p2), short(p1)), f)
        except Exception, inst:
            exc(lr, _("checking parents of %s") % short(node), inst, f)

        if node in seen:
            err(lr, _("duplicate revision %d (%d)") % (i, seen[n]), f)
        seen[n] = i
        return lr

    if os.path.exists(repo.sjoin("journal")):
        ui.warn(_("abandoned transaction found - run hg recover\n"))

    revlogv1 = cl.version != revlog.REVLOGV0
    if ui.verbose or not revlogv1:
        ui.status(_("repository uses revlog format %d\n") %
                       (revlogv1 and 1 or 0))

    havecl = len(cl) > 0
    havemf = len(mf) > 0

    ui.status(_("checking changesets\n"))
    seen = {}
    checklog(cl, "changelog", 0)
    total = len(repo)
    for i in repo:
        ui.progress(_('checking'), i, total=total, unit=_('changesets'))
        n = cl.node(i)
        checkentry(cl, i, n, seen, [i], "changelog")

        try:
            changes = cl.read(n)
            mflinkrevs.setdefault(changes[0], []).append(i)
            for f in changes[3]:
                filelinkrevs.setdefault(f, []).append(i)
        except Exception, inst:
            exc(i, _("unpacking changeset %s") % short(n), inst)
    ui.progress(_('checking'), None)

    ui.status(_("checking manifests\n"))
    seen = {}
    checklog(mf, "manifest", 0)
    total = len(mf)
    for i in mf:
        ui.progress(_('checking'), i, total=total, unit=_('manifests'))
        n = mf.node(i)
        lr = checkentry(mf, i, n, seen, mflinkrevs.get(n, []), "manifest")
        if n in mflinkrevs:
            del mflinkrevs[n]
        else:
            err(lr, _("%s not in changesets") % short(n), "manifest")

        try:
            for f, fn in mf.readdelta(n).iteritems():
                if not f:
                    err(lr, _("file without name in manifest"))
                elif f != "/dev/null":
                    filenodes.setdefault(f, {}).setdefault(fn, lr)
        except Exception, inst:
            exc(lr, _("reading manifest delta %s") % short(n), inst)
    ui.progress(_('checking'), None)

    ui.status(_("crosschecking files in changesets and manifests\n"))

    total = len(mflinkrevs) + len(filelinkrevs) + len(filenodes)
    count = 0
    if havemf:
        for c, m in sorted([(c, m) for m in mflinkrevs
                            for c in mflinkrevs[m]]):
            count += 1
            if m == nullid:
                continue
            ui.progress(_('crosschecking'), count, total=total)
            err(c, _("changeset refers to unknown manifest %s") % short(m))
        mflinkrevs = None # del is bad here due to scope issues

        for f in sorted(filelinkrevs):
            count += 1
            ui.progress(_('crosschecking'), count, total=total)
            if f not in filenodes:
                lr = filelinkrevs[f][0]
                err(lr, _("in changeset but not in manifest"), f)

    if havecl:
        for f in sorted(filenodes):
            count += 1
            ui.progress(_('crosschecking'), count, total=total)
            if f not in filelinkrevs:
                try:
                    fl = repo.file(f)
                    lr = min([fl.linkrev(fl.rev(n)) for n in filenodes[f]])
                except Exception:
                    lr = None
                err(lr, _("in manifest but not in changeset"), f)

    ui.progress(_('crosschecking'), None)

    ui.status(_("checking files\n"))

    storefiles = set()
    for f, f2, size in repo.store.datafiles():
        if not f:
            err(None, _("cannot decode filename '%s'") % f2)
        elif size > 0 or not revlogv1:
            storefiles.add(f)

    files = sorted(set(filenodes) | set(filelinkrevs))
    total = len(files)
    for i, f in enumerate(files):
        ui.progress(_('checking'), i, item=f, total=total)
        try:
            linkrevs = filelinkrevs[f]
        except KeyError:
            # in manifest but not in changelog
            linkrevs = []

        if linkrevs:
            lr = linkrevs[0]
        else:
            lr = None

        try:
            fl = repo.file(f)
        except error.RevlogError, e:
            err(lr, _("broken revlog! (%s)") % e, f)
            continue

        for ff in fl.files():
            try:
                storefiles.remove(ff)
            except KeyError:
                err(lr, _("missing revlog!"), ff)

        checklog(fl, f, lr)
        seen = {}
        rp = None
        for i in fl:
            revisions += 1
            n = fl.node(i)
            lr = checkentry(fl, i, n, seen, linkrevs, f)
            if f in filenodes:
                if havemf and n not in filenodes[f]:
                    err(lr, _("%s not in manifests") % (short(n)), f)
                else:
                    del filenodes[f][n]

            # verify contents
            try:
                l = len(fl.read(n))
                rp = fl.renamed(n)
                if l != fl.size(i):
                    if len(fl.revision(n)) != fl.size(i):
                        err(lr, _("unpacked size is %s, %s expected") %
                            (l, fl.size(i)), f)
            except Exception, inst:
                exc(lr, _("unpacking %s") % short(n), inst, f)

            # check renames
            try:
                if rp:
                    if lr is not None and ui.verbose:
                        ctx = lrugetctx(lr)
                        found = False
                        for pctx in ctx.parents():
                            if rp[0] in pctx:
                                found = True
                                break
                        if not found:
                            warn(_("warning: copy source of '%s' not"
                                   " in parents of %s") % (f, ctx))
                    fl2 = repo.file(rp[0])
                    if not len(fl2):
                        err(lr, _("empty or missing copy source revlog %s:%s")
                            % (rp[0], short(rp[1])), f)
                    elif rp[1] == nullid:
                        ui.note(_("warning: %s@%s: copy source"
                                  " revision is nullid %s:%s\n")
                            % (f, lr, rp[0], short(rp[1])))
                    else:
                        fl2.rev(rp[1])
            except Exception, inst:
                exc(lr, _("checking rename of %s") % short(n), inst, f)

        # cross-check
        if f in filenodes:
            fns = [(lr, n) for n, lr in filenodes[f].iteritems()]
            for lr, node in sorted(fns):
                err(lr, _("%s in manifests not found") % short(node), f)
    ui.progress(_('checking'), None)

    for f in storefiles:
        warn(_("warning: orphan revlog '%s'") % f)

    ui.status(_("%d files, %d changesets, %d total revisions\n") %
                   (len(files), len(cl), revisions))
    if warnings[0]:
        ui.warn(_("%d warnings encountered!\n") % warnings[0])
    if errors[0]:
        ui.warn(_("%d integrity errors encountered!\n") % errors[0])
        if badrevs:
            ui.warn(_("(first damaged changeset appears to be %d)\n")
                    % min(badrevs))
        return 1