verify: document the `checkentry` method

This method checks various core propertes of a revision. We document inputs, outputs
and the checks performed.

mercurial/verify.py

@@ -1,465 +1,484 b''
 # 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 __future__ import absolute_import
 
 import os
 
 from .i18n import _
 from .node import (
     nullid,
     short,
 )
 
 from . import (
     error,
     pycompat,
     revlog,
     util,
 )
 
 def verify(repo):
     with repo.lock():
         return verifier(repo).verify()
 
 def _normpath(f):
     # under hg < 2.4, convert didn't sanitize paths properly, so a
     # converted repo may contain repeated slashes
     while '//' in f:
         f = f.replace('//', '/')
     return f
 
 class verifier(object):
     def __init__(self, repo):
         self.repo = repo.unfiltered()
         self.ui = repo.ui
         self.match = repo.narrowmatch()
         self.badrevs = set()
         self.errors = 0
         self.warnings = 0
         self.havecl = len(repo.changelog) > 0
         self.havemf = len(repo.manifestlog.getstorage(b'')) > 0
         self.revlogv1 = repo.changelog.version != revlog.REVLOGV0
         self.lrugetctx = util.lrucachefunc(repo.__getitem__)
         self.refersmf = False
         self.fncachewarned = False
         # developer config: verify.skipflags
         self.skipflags = repo.ui.configint('verify', 'skipflags')
         self.warnorphanstorefiles = True
 
     def _warn(self, msg):
         """record a "warning" level issue"""
         self.ui.warn(msg + "\n")
         self.warnings += 1
 
     def _err(self, linkrev, msg, filename=None):
         """record a "error" level issue"""
         if linkrev is not None:
             self.badrevs.add(linkrev)
             linkrev = "%d" % linkrev
         else:
             linkrev = '?'
         msg = "%s: %s" % (linkrev, msg)
         if filename:
             msg = "%s@%s" % (filename, msg)
         self.ui.warn(" " + msg + "\n")
         self.errors += 1
 
     def _exc(self, linkrev, msg, inst, filename=None):
         """record exception raised during the verify process"""
         fmsg = pycompat.bytestr(inst)
         if not fmsg:
             fmsg = pycompat.byterepr(inst)
         self._err(linkrev, "%s: %s" % (msg, fmsg), filename)
 
     def checklog(self, obj, name, linkrev):
         if not len(obj) and (self.havecl or self.havemf):
             self._err(linkrev, _("empty or missing %s") % name)
             return
 
         d = obj.checksize()
         if d[0]:
             self.err(None, _("data length off by %d bytes") % d[0], name)
         if d[1]:
             self.err(None, _("index contains %d extra bytes") % d[1], name)
 
         if obj.version != revlog.REVLOGV0:
             if not self.revlogv1:
                 self._warn(_("warning: `%s' uses revlog format 1") % name)
         elif self.revlogv1:
             self._warn(_("warning: `%s' uses revlog format 0") % name)
 
     def checkentry(self, obj, i, node, seen, linkrevs, f):
+        """verify a single revlog entry
+
+        arguments are:
+        - obj:      the source revlog
+        - i:        the revision number
+        - node:        the revision node id
+        - seen:     nodes previously seen for this revlog
+        - linkrevs: [changelog-revisions] introducing "node"
+        - f:        string label ("changelog", "manifest", or filename)
+
+        Performs the following checks:
+        - linkrev points to an existing changelog revision,
+        - linkrev points to a changelog revision that introduces this revision,
+        - linkrev points to the lowest of these changesets,
+        - both parents exist in the revlog,
+        - the revision is not duplicated.
+
+        Return the linkrev of the revision (or None for changelog's revisions).
+        """
         lr = obj.linkrev(obj.rev(node))
         if lr < 0 or (self.havecl and lr not in linkrevs):
             if lr < 0 or lr >= len(self.repo.changelog):
                 msg = _("rev %d points to nonexistent changeset %d")
             else:
                 msg = _("rev %d points to unexpected changeset %d")
             self._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 self.lrugetctx(l)[f].filenode() == node]
                     except Exception:
                         pass
                 self._warn(_(" (expected %s)") % " ".join
                            (map(pycompat.bytestr, linkrevs)))
             lr = None # can't be trusted
 
         try:
             p1, p2 = obj.parents(node)
             if p1 not in seen and p1 != nullid:
                 self._err(lr, _("unknown parent 1 %s of %s") %
                     (short(p1), short(node)), f)
             if p2 not in seen and p2 != nullid:
                 self._err(lr, _("unknown parent 2 %s of %s") %
                     (short(p2), short(node)), f)
         except Exception as inst:
             self._exc(lr, _("checking parents of %s") % short(node), inst, f)
 
         if node in seen:
             self._err(lr, _("duplicate revision %d (%d)") % (i, seen[node]), f)
         seen[node] = i
         return lr
 
     def verify(self):
         """verify the content of the Mercurial repository
 
         This method run all verifications, displaying issues as they are found.
 
         return 1 if any error have been encountered, 0 otherwise."""
         # initial validation and generic report
         repo = self.repo
         ui = repo.ui
         if not repo.url().startswith('file:'):
             raise error.Abort(_("cannot verify bundle or remote repos"))
 
         if os.path.exists(repo.sjoin("journal")):
             ui.warn(_("abandoned transaction found - run hg recover\n"))
 
         if ui.verbose or not self.revlogv1:
             ui.status(_("repository uses revlog format %d\n") %
                            (self.revlogv1 and 1 or 0))
 
         # data verification
         mflinkrevs, filelinkrevs = self._verifychangelog()
         filenodes = self._verifymanifest(mflinkrevs)
         del mflinkrevs
         self._crosscheckfiles(filelinkrevs, filenodes)
         totalfiles, filerevisions = self._verifyfiles(filenodes, filelinkrevs)
 
         # final report
         ui.status(_("checked %d changesets with %d changes to %d files\n") %
                        (len(repo.changelog), filerevisions, totalfiles))
         if self.warnings:
             ui.warn(_("%d warnings encountered!\n") % self.warnings)
         if self.fncachewarned:
             ui.warn(_('hint: run "hg debugrebuildfncache" to recover from '
                       'corrupt fncache\n'))
         if self.errors:
             ui.warn(_("%d integrity errors encountered!\n") % self.errors)
             if self.badrevs:
                 ui.warn(_("(first damaged changeset appears to be %d)\n")
                         % min(self.badrevs))
             return 1
         return 0
 
     def _verifychangelog(self):
         ui = self.ui
         repo = self.repo
         match = self.match
         cl = repo.changelog
 
         ui.status(_("checking changesets\n"))
         mflinkrevs = {}
         filelinkrevs = {}
         seen = {}
         self.checklog(cl, "changelog", 0)
         progress = ui.makeprogress(_('checking'), unit=_('changesets'),
                                    total=len(repo))
         for i in repo:
             progress.update(i)
             n = cl.node(i)
             self.checkentry(cl, i, n, seen, [i], "changelog")
 
             try:
                 changes = cl.read(n)
                 if changes[0] != nullid:
                     mflinkrevs.setdefault(changes[0], []).append(i)
                     self.refersmf = True
                 for f in changes[3]:
                     if match(f):
                         filelinkrevs.setdefault(_normpath(f), []).append(i)
             except Exception as inst:
                 self.refersmf = True
                 self._exc(i, _("unpacking changeset %s") % short(n), inst)
         progress.complete()
         return mflinkrevs, filelinkrevs
 
     def _verifymanifest(self, mflinkrevs, dir="", storefiles=None,
                         subdirprogress=None):
         repo = self.repo
         ui = self.ui
         match = self.match
         mfl = self.repo.manifestlog
         mf = mfl.getstorage(dir)
 
         if not dir:
             self.ui.status(_("checking manifests\n"))
 
         filenodes = {}
         subdirnodes = {}
         seen = {}
         label = "manifest"
         if dir:
             label = dir
             revlogfiles = mf.files()
             storefiles.difference_update(revlogfiles)
             if subdirprogress: # should be true since we're in a subdirectory
                 subdirprogress.increment()
         if self.refersmf:
             # Do not check manifest if there are only changelog entries with
             # null manifests.
             self.checklog(mf, label, 0)
         progress = ui.makeprogress(_('checking'), unit=_('manifests'),
                                    total=len(mf))
         for i in mf:
             if not dir:
                 progress.update(i)
             n = mf.node(i)
             lr = self.checkentry(mf, i, n, seen, mflinkrevs.get(n, []), label)
             if n in mflinkrevs:
                 del mflinkrevs[n]
             elif dir:
                 self._err(lr, _("%s not in parent-directory manifest") %
                          short(n), label)
             else:
                 self._err(lr, _("%s not in changesets") % short(n), label)
 
             try:
                 mfdelta = mfl.get(dir, n).readdelta(shallow=True)
                 for f, fn, fl in mfdelta.iterentries():
                     if not f:
                         self._err(lr, _("entry without name in manifest"))
                     elif f == "/dev/null":  # ignore this in very old repos
                         continue
                     fullpath = dir + _normpath(f)
                     if fl == 't':
                         if not match.visitdir(fullpath):
                             continue
                         subdirnodes.setdefault(fullpath + '/', {}).setdefault(
                             fn, []).append(lr)
                     else:
                         if not match(fullpath):
                             continue
                         filenodes.setdefault(fullpath, {}).setdefault(fn, lr)
             except Exception as inst:
                 self._exc(lr, _("reading delta %s") % short(n), inst, label)
         if not dir:
             progress.complete()
 
         if self.havemf:
             for c, m in sorted([(c, m) for m in mflinkrevs
                         for c in mflinkrevs[m]]):
                 if dir:
                     self._err(c, _("parent-directory manifest refers to unknown"
                                    " revision %s") % short(m), label)
                 else:
                     self._err(c, _("changeset refers to unknown revision %s") %
                               short(m), label)
 
         if not dir and subdirnodes:
             self.ui.status(_("checking directory manifests\n"))
             storefiles = set()
             subdirs = set()
             revlogv1 = self.revlogv1
             for f, f2, size in repo.store.datafiles():
                 if not f:
                     self._err(None, _("cannot decode filename '%s'") % f2)
                 elif (size > 0 or not revlogv1) and f.startswith('meta/'):
                     storefiles.add(_normpath(f))
                     subdirs.add(os.path.dirname(f))
             subdirprogress = ui.makeprogress(_('checking'), unit=_('manifests'),
                                              total=len(subdirs))
 
         for subdir, linkrevs in subdirnodes.iteritems():
             subdirfilenodes = self._verifymanifest(linkrevs, subdir, storefiles,
                                                    subdirprogress)
             for f, onefilenodes in subdirfilenodes.iteritems():
                 filenodes.setdefault(f, {}).update(onefilenodes)
 
         if not dir and subdirnodes:
             subdirprogress.complete()
             if self.warnorphanstorefiles:
                 for f in sorted(storefiles):
                     self._warn(_("warning: orphan data file '%s'") % f)
 
         return filenodes
 
     def _crosscheckfiles(self, filelinkrevs, filenodes):
         repo = self.repo
         ui = self.ui
         ui.status(_("crosschecking files in changesets and manifests\n"))
 
         total = len(filelinkrevs) + len(filenodes)
         progress = ui.makeprogress(_('crosschecking'), unit=_('files'),
                                    total=total)
         if self.havemf:
             for f in sorted(filelinkrevs):
                 progress.increment()
                 if f not in filenodes:
                     lr = filelinkrevs[f][0]
                     self._err(lr, _("in changeset but not in manifest"), f)
 
         if self.havecl:
             for f in sorted(filenodes):
                 progress.increment()
                 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
                     self._err(lr, _("in manifest but not in changeset"), f)
 
         progress.complete()
 
     def _verifyfiles(self, filenodes, filelinkrevs):
         repo = self.repo
         ui = self.ui
         lrugetctx = self.lrugetctx
         revlogv1 = self.revlogv1
         havemf = self.havemf
         ui.status(_("checking files\n"))
 
         storefiles = set()
         for f, f2, size in repo.store.datafiles():
             if not f:
                 self._err(None, _("cannot decode filename '%s'") % f2)
             elif (size > 0 or not revlogv1) and f.startswith('data/'):
                 storefiles.add(_normpath(f))
 
         state = {
             # TODO this assumes revlog storage for changelog.
             'expectedversion': self.repo.changelog.version & 0xFFFF,
             'skipflags': self.skipflags,
             # experimental config: censor.policy
             'erroroncensored': ui.config('censor', 'policy') == 'abort',
         }
 
         files = sorted(set(filenodes) | set(filelinkrevs))
         revisions = 0
         progress = ui.makeprogress(_('checking'), unit=_('files'),
                                    total=len(files))
         for i, f in enumerate(files):
             progress.update(i, item=f)
             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.StorageError as e:
                 self._err(lr, _("broken revlog! (%s)") % e, f)
                 continue
 
             for ff in fl.files():
                 try:
                     storefiles.remove(ff)
                 except KeyError:
                     if self.warnorphanstorefiles:
                         self._warn(_(" warning: revlog '%s' not in fncache!") %
                                   ff)
                         self.fncachewarned = True
 
             if not len(fl) and (self.havecl or self.havemf):
                 self._err(lr, _("empty or missing %s") % f)
             else:
                 # Guard against implementations not setting this.
                 state['skipread'] = set()
                 for problem in fl.verifyintegrity(state):
                     if problem.node is not None:
                         linkrev = fl.linkrev(fl.rev(problem.node))
                     else:
                         linkrev = None
 
                     if problem.warning:
                         self._warn(problem.warning)
                     elif problem.error:
                         self._err(linkrev if linkrev is not None else lr,
                                   problem.error, f)
                     else:
                         raise error.ProgrammingError(
                             'problem instance does not set warning or error '
                             'attribute: %s' % problem.msg)
 
             seen = {}
             for i in fl:
                 revisions += 1
                 n = fl.node(i)
                 lr = self.checkentry(fl, i, n, seen, linkrevs, f)
                 if f in filenodes:
                     if havemf and n not in filenodes[f]:
                         self._err(lr, _("%s not in manifests") % (short(n)), f)
                     else:
                         del filenodes[f][n]
 
                 if n in state['skipread']:
                     continue
 
                 # check renames
                 try:
                     # This requires resolving fulltext (at least on revlogs). We
                     # may want ``verifyintegrity()`` to pass a set of nodes with
                     # rename metadata as an optimization.
                     rp = fl.renamed(n)
                     if rp:
                         if lr is not None and ui.verbose:
                             ctx = lrugetctx(lr)
                             if not any(rp[0] in pctx for pctx in ctx.parents()):
                                 self._warn(_("warning: copy source of '%s' not"
                                             " in parents of %s") % (f, ctx))
                         fl2 = repo.file(rp[0])
                         if not len(fl2):
                             self._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 as inst:
                     self._exc(lr, _("checking rename of %s") % short(n),
                               inst, f)
 
             # cross-check
             if f in filenodes:
                 fns = [(v, k) for k, v in filenodes[f].iteritems()]
                 for lr, node in sorted(fns):
                     self._err(lr, _("manifest refers to unknown revision %s") %
                               short(node), f)
         progress.complete()
 
         if self.warnorphanstorefiles:
             for f in sorted(storefiles):
                 self._warn(_("warning: orphan data file '%s'") % f)
 
         return len(files), revisions