repair: mark the critical section of strip() as unsafe

When our experimental nointerrupt feature is enabled, this will
help prevent users from corrupting their repo during a strip.

Differential Revision: https://phab.mercurial-scm.org/D3717

mercurial/repair.py

@@ -1,435 +1,436
 # repair.py - functions for repository repair for mercurial
 #
 # Copyright 2005, 2006 Chris Mason <[e-mail]>
 # Copyright 2007 Matt Mackall
 #
 # 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
 
 import errno
 import hashlib
 
 from .i18n import _
 from .node import (
     hex,
     short,
 )
 from . import (
     bundle2,
     changegroup,
     discovery,
     error,
     exchange,
     obsolete,
     obsutil,
     util,
 )
 from .utils import (
     stringutil,
 )
 
 def backupbundle(repo, bases, heads, node, suffix, compress=True,
                  obsolescence=True):
     """create a bundle with the specified revisions as a backup"""
 
     backupdir = "strip-backup"
     vfs = repo.vfs
     if not vfs.isdir(backupdir):
         vfs.mkdir(backupdir)
 
     # Include a hash of all the nodes in the filename for uniqueness
     allcommits = repo.set('%ln::%ln', bases, heads)
     allhashes = sorted(c.hex() for c in allcommits)
     totalhash = hashlib.sha1(''.join(allhashes)).digest()
     name = "%s/%s-%s-%s.hg" % (backupdir, short(node),
                                hex(totalhash[:4]), suffix)
 
     cgversion = changegroup.localversion(repo)
     comp = None
     if cgversion != '01':
         bundletype = "HG20"
         if compress:
             comp = 'BZ'
     elif compress:
         bundletype = "HG10BZ"
     else:
         bundletype = "HG10UN"
 
     outgoing = discovery.outgoing(repo, missingroots=bases, missingheads=heads)
     contentopts = {
         'cg.version': cgversion,
         'obsolescence': obsolescence,
         'phases': True,
     }
     return bundle2.writenewbundle(repo.ui, repo, 'strip', name, bundletype,
                                   outgoing, contentopts, vfs, compression=comp)
 
 def _collectfiles(repo, striprev):
     """find out the filelogs affected by the strip"""
     files = set()
 
     for x in xrange(striprev, len(repo)):
         files.update(repo[x].files())
 
     return sorted(files)
 
 def _collectrevlog(revlog, striprev):
     _, brokenset = revlog.getstrippoint(striprev)
     return [revlog.linkrev(r) for r in brokenset]
 
 def _collectmanifest(repo, striprev):
     return _collectrevlog(repo.manifestlog._revlog, striprev)
 
 def _collectbrokencsets(repo, files, striprev):
     """return the changesets which will be broken by the truncation"""
     s = set()
 
     s.update(_collectmanifest(repo, striprev))
     for fname in files:
         s.update(_collectrevlog(repo.file(fname), striprev))
 
     return s
 
 def strip(ui, repo, nodelist, backup=True, topic='backup'):
     # This function requires the caller to lock the repo, but it operates
     # within a transaction of its own, and thus requires there to be no current
     # transaction when it is called.
     if repo.currenttransaction() is not None:
         raise error.ProgrammingError('cannot strip from inside a transaction')
 
     # Simple way to maintain backwards compatibility for this
     # argument.
     if backup in ['none', 'strip']:
         backup = False
 
     repo = repo.unfiltered()
     repo.destroying()
 
     cl = repo.changelog
     # TODO handle undo of merge sets
     if isinstance(nodelist, str):
         nodelist = [nodelist]
     striplist = [cl.rev(node) for node in nodelist]
     striprev = min(striplist)
 
     files = _collectfiles(repo, striprev)
     saverevs = _collectbrokencsets(repo, files, striprev)
 
     # Some revisions with rev > striprev may not be descendants of striprev.
     # We have to find these revisions and put them in a bundle, so that
     # we can restore them after the truncations.
     # To create the bundle we use repo.changegroupsubset which requires
     # the list of heads and bases of the set of interesting revisions.
     # (head = revision in the set that has no descendant in the set;
     #  base = revision in the set that has no ancestor in the set)
     tostrip = set(striplist)
     saveheads = set(saverevs)
     for r in cl.revs(start=striprev + 1):
         if any(p in tostrip for p in cl.parentrevs(r)):
             tostrip.add(r)
 
         if r not in tostrip:
             saverevs.add(r)
             saveheads.difference_update(cl.parentrevs(r))
             saveheads.add(r)
     saveheads = [cl.node(r) for r in saveheads]
 
     # compute base nodes
     if saverevs:
         descendants = set(cl.descendants(saverevs))
         saverevs.difference_update(descendants)
     savebases = [cl.node(r) for r in saverevs]
     stripbases = [cl.node(r) for r in tostrip]
 
     stripobsidx = obsmarkers = ()
     if repo.ui.configbool('devel', 'strip-obsmarkers'):
         obsmarkers = obsutil.exclusivemarkers(repo, stripbases)
     if obsmarkers:
         stripobsidx = [i for i, m in enumerate(repo.obsstore)
                        if m in obsmarkers]
 
     # For a set s, max(parents(s) - s) is the same as max(heads(::s - s)), but
     # is much faster
     newbmtarget = repo.revs('max(parents(%ld) - (%ld))', tostrip, tostrip)
     if newbmtarget:
         newbmtarget = repo[newbmtarget.first()].node()
     else:
         newbmtarget = '.'
 
     bm = repo._bookmarks
     updatebm = []
     for m in bm:
         rev = repo[bm[m]].rev()
         if rev in tostrip:
             updatebm.append(m)
 
     # create a changegroup for all the branches we need to keep
     backupfile = None
     vfs = repo.vfs
     node = nodelist[-1]
     if backup:
         backupfile = backupbundle(repo, stripbases, cl.heads(), node, topic)
         repo.ui.status(_("saved backup bundle to %s\n") %
                        vfs.join(backupfile))
         repo.ui.log("backupbundle", "saved backup bundle to %s\n",
                     vfs.join(backupfile))
     tmpbundlefile = None
     if saveheads:
         # do not compress temporary bundle if we remove it from disk later
         #
         # We do not include obsolescence, it might re-introduce prune markers
         # we are trying to strip.  This is harmless since the stripped markers
         # are already backed up and we did not touched the markers for the
         # saved changesets.
         tmpbundlefile = backupbundle(repo, savebases, saveheads, node, 'temp',
                                      compress=False, obsolescence=False)
 
-    try:
-        with repo.transaction("strip") as tr:
-            offset = len(tr.entries)
+    with ui.uninterruptable():
+        try:
+            with repo.transaction("strip") as tr:
+                offset = len(tr.entries)
 
-            tr.startgroup()
-            cl.strip(striprev, tr)
-            stripmanifest(repo, striprev, tr, files)
-
-            for fn in files:
-                repo.file(fn).strip(striprev, tr)
-            tr.endgroup()
+                tr.startgroup()
+                cl.strip(striprev, tr)
+                stripmanifest(repo, striprev, tr, files)
 
-            for i in xrange(offset, len(tr.entries)):
-                file, troffset, ignore = tr.entries[i]
-                with repo.svfs(file, 'a', checkambig=True) as fp:
-                    fp.truncate(troffset)
-                if troffset == 0:
-                    repo.store.markremoved(file)
+                for fn in files:
+                    repo.file(fn).strip(striprev, tr)
+                tr.endgroup()
 
-            deleteobsmarkers(repo.obsstore, stripobsidx)
-            del repo.obsstore
-            repo.invalidatevolatilesets()
-            repo._phasecache.filterunknown(repo)
+                for i in xrange(offset, len(tr.entries)):
+                    file, troffset, ignore = tr.entries[i]
+                    with repo.svfs(file, 'a', checkambig=True) as fp:
+                        fp.truncate(troffset)
+                    if troffset == 0:
+                        repo.store.markremoved(file)
+
+                deleteobsmarkers(repo.obsstore, stripobsidx)
+                del repo.obsstore
+                repo.invalidatevolatilesets()
+                repo._phasecache.filterunknown(repo)
 
-        if tmpbundlefile:
-            ui.note(_("adding branch\n"))
-            f = vfs.open(tmpbundlefile, "rb")
-            gen = exchange.readbundle(ui, f, tmpbundlefile, vfs)
-            if not repo.ui.verbose:
-                # silence internal shuffling chatter
-                repo.ui.pushbuffer()
-            tmpbundleurl = 'bundle:' + vfs.join(tmpbundlefile)
-            txnname = 'strip'
-            if not isinstance(gen, bundle2.unbundle20):
-                txnname = "strip\n%s" % util.hidepassword(tmpbundleurl)
-            with repo.transaction(txnname) as tr:
-                bundle2.applybundle(repo, gen, tr, source='strip',
-                                    url=tmpbundleurl)
-            if not repo.ui.verbose:
-                repo.ui.popbuffer()
-            f.close()
+            if tmpbundlefile:
+                ui.note(_("adding branch\n"))
+                f = vfs.open(tmpbundlefile, "rb")
+                gen = exchange.readbundle(ui, f, tmpbundlefile, vfs)
+                if not repo.ui.verbose:
+                    # silence internal shuffling chatter
+                    repo.ui.pushbuffer()
+                tmpbundleurl = 'bundle:' + vfs.join(tmpbundlefile)
+                txnname = 'strip'
+                if not isinstance(gen, bundle2.unbundle20):
+                    txnname = "strip\n%s" % util.hidepassword(tmpbundleurl)
+                with repo.transaction(txnname) as tr:
+                    bundle2.applybundle(repo, gen, tr, source='strip',
+                                        url=tmpbundleurl)
+                if not repo.ui.verbose:
+                    repo.ui.popbuffer()
+                f.close()
 
-        with repo.transaction('repair') as tr:
-            bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm]
-            bm.applychanges(repo, tr, bmchanges)
+            with repo.transaction('repair') as tr:
+                bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm]
+                bm.applychanges(repo, tr, bmchanges)
 
-        # remove undo files
-        for undovfs, undofile in repo.undofiles():
-            try:
-                undovfs.unlink(undofile)
-            except OSError as e:
-                if e.errno != errno.ENOENT:
-                    ui.warn(_('error removing %s: %s\n') %
-                            (undovfs.join(undofile),
-                             stringutil.forcebytestr(e)))
+            # remove undo files
+            for undovfs, undofile in repo.undofiles():
+                try:
+                    undovfs.unlink(undofile)
+                except OSError as e:
+                    if e.errno != errno.ENOENT:
+                        ui.warn(_('error removing %s: %s\n') %
+                                (undovfs.join(undofile),
+                                 stringutil.forcebytestr(e)))
 
-    except: # re-raises
-        if backupfile:
-            ui.warn(_("strip failed, backup bundle stored in '%s'\n")
-                    % vfs.join(backupfile))
-        if tmpbundlefile:
-            ui.warn(_("strip failed, unrecovered changes stored in '%s'\n")
-                    % vfs.join(tmpbundlefile))
-            ui.warn(_("(fix the problem, then recover the changesets with "
-                      "\"hg unbundle '%s'\")\n") % vfs.join(tmpbundlefile))
-        raise
-    else:
-        if tmpbundlefile:
-            # Remove temporary bundle only if there were no exceptions
-            vfs.unlink(tmpbundlefile)
+        except: # re-raises
+            if backupfile:
+                ui.warn(_("strip failed, backup bundle stored in '%s'\n")
+                        % vfs.join(backupfile))
+            if tmpbundlefile:
+                ui.warn(_("strip failed, unrecovered changes stored in '%s'\n")
+                        % vfs.join(tmpbundlefile))
+                ui.warn(_("(fix the problem, then recover the changesets with "
+                          "\"hg unbundle '%s'\")\n") % vfs.join(tmpbundlefile))
+            raise
+        else:
+            if tmpbundlefile:
+                # Remove temporary bundle only if there were no exceptions
+                vfs.unlink(tmpbundlefile)
 
     repo.destroyed()
     # return the backup file path (or None if 'backup' was False) so
     # extensions can use it
     return backupfile
 
 def safestriproots(ui, repo, nodes):
     """return list of roots of nodes where descendants are covered by nodes"""
     torev = repo.unfiltered().changelog.rev
     revs = set(torev(n) for n in nodes)
     # tostrip = wanted - unsafe = wanted - ancestors(orphaned)
     # orphaned = affected - wanted
     # affected = descendants(roots(wanted))
     # wanted = revs
     tostrip = set(repo.revs('%ld-(::((roots(%ld)::)-%ld))', revs, revs, revs))
     notstrip = revs - tostrip
     if notstrip:
         nodestr = ', '.join(sorted(short(repo[n].node()) for n in notstrip))
         ui.warn(_('warning: orphaned descendants detected, '
                   'not stripping %s\n') % nodestr)
     return [c.node() for c in repo.set('roots(%ld)', tostrip)]
 
 class stripcallback(object):
     """used as a transaction postclose callback"""
 
     def __init__(self, ui, repo, backup, topic):
         self.ui = ui
         self.repo = repo
         self.backup = backup
         self.topic = topic or 'backup'
         self.nodelist = []
 
     def addnodes(self, nodes):
         self.nodelist.extend(nodes)
 
     def __call__(self, tr):
         roots = safestriproots(self.ui, self.repo, self.nodelist)
         if roots:
             strip(self.ui, self.repo, roots, self.backup, self.topic)
 
 def delayedstrip(ui, repo, nodelist, topic=None):
     """like strip, but works inside transaction and won't strip irreverent revs
 
     nodelist must explicitly contain all descendants. Otherwise a warning will
     be printed that some nodes are not stripped.
 
     Always do a backup. The last non-None "topic" will be used as the backup
     topic name. The default backup topic name is "backup".
     """
     tr = repo.currenttransaction()
     if not tr:
         nodes = safestriproots(ui, repo, nodelist)
         return strip(ui, repo, nodes, True, topic)
     # transaction postclose callbacks are called in alphabet order.
     # use '\xff' as prefix so we are likely to be called last.
     callback = tr.getpostclose('\xffstrip')
     if callback is None:
         callback = stripcallback(ui, repo, True, topic)
         tr.addpostclose('\xffstrip', callback)
     if topic:
         callback.topic = topic
     callback.addnodes(nodelist)
 
 def stripmanifest(repo, striprev, tr, files):
     revlog = repo.manifestlog._revlog
     revlog.strip(striprev, tr)
     striptrees(repo, tr, striprev, files)
 
 def striptrees(repo, tr, striprev, files):
     if 'treemanifest' in repo.requirements: # safe but unnecessary
                                             # otherwise
         for unencoded, encoded, size in repo.store.datafiles():
             if (unencoded.startswith('meta/') and
                 unencoded.endswith('00manifest.i')):
                 dir = unencoded[5:-12]
                 repo.manifestlog._revlog.dirlog(dir).strip(striprev, tr)
 
 def rebuildfncache(ui, repo):
     """Rebuilds the fncache file from repo history.
 
     Missing entries will be added. Extra entries will be removed.
     """
     repo = repo.unfiltered()
 
     if 'fncache' not in repo.requirements:
         ui.warn(_('(not rebuilding fncache because repository does not '
                   'support fncache)\n'))
         return
 
     with repo.lock():
         fnc = repo.store.fncache
         # Trigger load of fncache.
         if 'irrelevant' in fnc:
             pass
 
         oldentries = set(fnc.entries)
         newentries = set()
         seenfiles = set()
 
         progress = ui.makeprogress(_('rebuilding'), unit=_('changesets'),
                                    total=len(repo))
         for rev in repo:
             progress.update(rev)
 
             ctx = repo[rev]
             for f in ctx.files():
                 # This is to minimize I/O.
                 if f in seenfiles:
                     continue
                 seenfiles.add(f)
 
                 i = 'data/%s.i' % f
                 d = 'data/%s.d' % f
 
                 if repo.store._exists(i):
                     newentries.add(i)
                 if repo.store._exists(d):
                     newentries.add(d)
 
         progress.complete()
 
         if 'treemanifest' in repo.requirements: # safe but unnecessary otherwise
             for dir in util.dirs(seenfiles):
                 i = 'meta/%s/00manifest.i' % dir
                 d = 'meta/%s/00manifest.d' % dir
 
                 if repo.store._exists(i):
                     newentries.add(i)
                 if repo.store._exists(d):
                     newentries.add(d)
 
         addcount = len(newentries - oldentries)
         removecount = len(oldentries - newentries)
         for p in sorted(oldentries - newentries):
             ui.write(_('removing %s\n') % p)
         for p in sorted(newentries - oldentries):
             ui.write(_('adding %s\n') % p)
 
         if addcount or removecount:
             ui.write(_('%d items added, %d removed from fncache\n') %
                      (addcount, removecount))
             fnc.entries = newentries
             fnc._dirty = True
 
             with repo.transaction('fncache') as tr:
                 fnc.write(tr)
         else:
             ui.write(_('fncache already up to date\n'))
 
 def deleteobsmarkers(obsstore, indices):
     """Delete some obsmarkers from obsstore and return how many were deleted
 
     'indices' is a list of ints which are the indices
     of the markers to be deleted.
 
     Every invocation of this function completely rewrites the obsstore file,
     skipping the markers we want to be removed. The new temporary file is
     created, remaining markers are written there and on .close() this file
     gets atomically renamed to obsstore, thus guaranteeing consistency."""
     if not indices:
         # we don't want to rewrite the obsstore with the same content
         return
 
     left = []
     current = obsstore._all
     n = 0
     for i, m in enumerate(current):
         if i in indices:
             n += 1
             continue
         left.append(m)
 
     newobsstorefile = obsstore.svfs('obsstore', 'w', atomictemp=True)
     for bytes in obsolete.encodemarkers(left, True, obsstore._version):
         newobsstorefile.write(bytes)
     newobsstorefile.close()
     return n