tags: fix typo in fast path detection of fnode resolution (issue6673)

If I understand it, mctx.readfast() is unreliable here if p1/p2 .hgtags
nodes differ, and tags on that branch would be randomly discarded
depending on which parent were picked.

The test case added by this patch would fail only on zstd-compressed
repository. I didn't try hard to stabilize the failure case.

mercurial/tags.py

@@ -1,915 +1,915 b''
 # tags.py - read tag info from local repository
 #
 # Copyright 2009 Olivia Mackall <[e-mail]>
 # Copyright 2009 Greg Ward <[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.
 
 # Currently this module only deals with reading and caching tags.
 # Eventually, it could take care of updating (adding/removing/moving)
 # tags too.
 
 from __future__ import absolute_import
 
 import errno
 import io
 
 from .node import (
     bin,
     hex,
     nullrev,
     short,
 )
 from .i18n import _
 from . import (
     encoding,
     error,
     match as matchmod,
     pycompat,
     scmutil,
     util,
 )
 from .utils import stringutil
 
 # Tags computation can be expensive and caches exist to make it fast in
 # the common case.
 #
 # The "hgtagsfnodes1" cache file caches the .hgtags filenode values for
 # each revision in the repository. The file is effectively an array of
 # fixed length records. Read the docs for "hgtagsfnodescache" for technical
 # details.
 #
 # The .hgtags filenode cache grows in proportion to the length of the
 # changelog. The file is truncated when the # changelog is stripped.
 #
 # The purpose of the filenode cache is to avoid the most expensive part
 # of finding global tags, which is looking up the .hgtags filenode in the
 # manifest for each head. This can take dozens or over 100ms for
 # repositories with very large manifests. Multiplied by dozens or even
 # hundreds of heads and there is a significant performance concern.
 #
 # There also exist a separate cache file for each repository filter.
 # These "tags-*" files store information about the history of tags.
 #
 # The tags cache files consists of a cache validation line followed by
 # a history of tags.
 #
 # The cache validation line has the format:
 #
 #   <tiprev> <tipnode> [<filteredhash>]
 #
 # <tiprev> is an integer revision and <tipnode> is a 40 character hex
 # node for that changeset. These redundantly identify the repository
 # tip from the time the cache was written. In addition, <filteredhash>,
 # if present, is a 40 character hex hash of the contents of the filtered
 # revisions for this filter. If the set of filtered revs changes, the
 # hash will change and invalidate the cache.
 #
 # The history part of the tags cache consists of lines of the form:
 #
 #   <node> <tag>
 #
 # (This format is identical to that of .hgtags files.)
 #
 # <tag> is the tag name and <node> is the 40 character hex changeset
 # the tag is associated with.
 #
 # Tags are written sorted by tag name.
 #
 # Tags associated with multiple changesets have an entry for each changeset.
 # The most recent changeset (in terms of revlog ordering for the head
 # setting it) for each tag is last.
 
 
 def fnoderevs(ui, repo, revs):
     """return the list of '.hgtags' fnodes used in a set revisions
 
     This is returned as list of unique fnodes. We use a list instead of a set
     because order matters when it comes to tags."""
     unfi = repo.unfiltered()
     tonode = unfi.changelog.node
     nodes = [tonode(r) for r in revs]
     fnodes = _getfnodes(ui, repo, nodes)
     fnodes = _filterfnodes(fnodes, nodes)
     return fnodes
 
 
 def _nulltonone(repo, value):
     """convert nullid to None
 
     For tag value, nullid means "deleted". This small utility function helps
     translating that to None."""
     if value == repo.nullid:
         return None
     return value
 
 
 def difftags(ui, repo, oldfnodes, newfnodes):
     """list differences between tags expressed in two set of file-nodes
 
     The list contains entries in the form: (tagname, oldvalue, new value).
     None is used to expressed missing value:
         ('foo', None, 'abcd') is a new tag,
         ('bar', 'ef01', None) is a deletion,
         ('baz', 'abcd', 'ef01') is a tag movement.
     """
     if oldfnodes == newfnodes:
         return []
     oldtags = _tagsfromfnodes(ui, repo, oldfnodes)
     newtags = _tagsfromfnodes(ui, repo, newfnodes)
 
     # list of (tag, old, new): None means missing
     entries = []
     for tag, (new, __) in newtags.items():
         new = _nulltonone(repo, new)
         old, __ = oldtags.pop(tag, (None, None))
         old = _nulltonone(repo, old)
         if old != new:
             entries.append((tag, old, new))
     # handle deleted tags
     for tag, (old, __) in oldtags.items():
         old = _nulltonone(repo, old)
         if old is not None:
             entries.append((tag, old, None))
     entries.sort()
     return entries
 
 
 def writediff(fp, difflist):
     """write tags diff information to a file.
 
     Data are stored with a line based format:
 
         <action> <hex-node> <tag-name>\n
 
     Action are defined as follow:
        -R tag is removed,
        +A tag is added,
        -M tag is moved (old value),
        +M tag is moved (new value),
 
     Example:
 
          +A 875517b4806a848f942811a315a5bce30804ae85 t5
 
     See documentation of difftags output for details about the input.
     """
     add = b'+A %s %s\n'
     remove = b'-R %s %s\n'
     updateold = b'-M %s %s\n'
     updatenew = b'+M %s %s\n'
     for tag, old, new in difflist:
         # translate to hex
         if old is not None:
             old = hex(old)
         if new is not None:
             new = hex(new)
         # write to file
         if old is None:
             fp.write(add % (new, tag))
         elif new is None:
             fp.write(remove % (old, tag))
         else:
             fp.write(updateold % (old, tag))
             fp.write(updatenew % (new, tag))
 
 
 def findglobaltags(ui, repo):
     """Find global tags in a repo: return a tagsmap
 
     tagsmap: tag name to (node, hist) 2-tuples.
 
     The tags cache is read and updated as a side-effect of calling.
     """
     (heads, tagfnode, valid, cachetags, shouldwrite) = _readtagcache(ui, repo)
     if cachetags is not None:
         assert not shouldwrite
         # XXX is this really 100% correct?  are there oddball special
         # cases where a global tag should outrank a local tag but won't,
         # because cachetags does not contain rank info?
         alltags = {}
         _updatetags(cachetags, alltags)
         return alltags
 
     for head in reversed(heads):  # oldest to newest
         assert repo.changelog.index.has_node(
             head
         ), b"tag cache returned bogus head %s" % short(head)
     fnodes = _filterfnodes(tagfnode, reversed(heads))
     alltags = _tagsfromfnodes(ui, repo, fnodes)
 
     # and update the cache (if necessary)
     if shouldwrite:
         _writetagcache(ui, repo, valid, alltags)
     return alltags
 
 
 def _filterfnodes(tagfnode, nodes):
     """return a list of unique fnodes
 
     The order of this list matches the order of "nodes". Preserving this order
     is important as reading tags in different order provides different
     results."""
     seen = set()  # set of fnode
     fnodes = []
     for no in nodes:  # oldest to newest
         fnode = tagfnode.get(no)
         if fnode and fnode not in seen:
             seen.add(fnode)
             fnodes.append(fnode)
     return fnodes
 
 
 def _tagsfromfnodes(ui, repo, fnodes):
     """return a tagsmap from a list of file-node
 
     tagsmap: tag name to (node, hist) 2-tuples.
 
     The order of the list matters."""
     alltags = {}
     fctx = None
     for fnode in fnodes:
         if fctx is None:
             fctx = repo.filectx(b'.hgtags', fileid=fnode)
         else:
             fctx = fctx.filectx(fnode)
         filetags = _readtags(ui, repo, fctx.data().splitlines(), fctx)
         _updatetags(filetags, alltags)
     return alltags
 
 
 def readlocaltags(ui, repo, alltags, tagtypes):
     '''Read local tags in repo. Update alltags and tagtypes.'''
     try:
         data = repo.vfs.read(b"localtags")
     except IOError as inst:
         if inst.errno != errno.ENOENT:
             raise
         return
 
     # localtags is in the local encoding; re-encode to UTF-8 on
     # input for consistency with the rest of this module.
     filetags = _readtags(
         ui, repo, data.splitlines(), b"localtags", recode=encoding.fromlocal
     )
 
     # remove tags pointing to invalid nodes
     cl = repo.changelog
     for t in list(filetags):
         try:
             cl.rev(filetags[t][0])
         except (LookupError, ValueError):
             del filetags[t]
 
     _updatetags(filetags, alltags, b'local', tagtypes)
 
 
 def _readtaghist(ui, repo, lines, fn, recode=None, calcnodelines=False):
     """Read tag definitions from a file (or any source of lines).
 
     This function returns two sortdicts with similar information:
 
     - the first dict, bintaghist, contains the tag information as expected by
       the _readtags function, i.e. a mapping from tag name to (node, hist):
         - node is the node id from the last line read for that name,
         - hist is the list of node ids previously associated with it (in file
           order). All node ids are binary, not hex.
 
     - the second dict, hextaglines, is a mapping from tag name to a list of
       [hexnode, line number] pairs, ordered from the oldest to the newest node.
 
     When calcnodelines is False the hextaglines dict is not calculated (an
     empty dict is returned). This is done to improve this function's
     performance in cases where the line numbers are not needed.
     """
 
     bintaghist = util.sortdict()
     hextaglines = util.sortdict()
     count = 0
 
     def dbg(msg):
         ui.debug(b"%s, line %d: %s\n" % (fn, count, msg))
 
     for nline, line in enumerate(lines):
         count += 1
         if not line:
             continue
         try:
             (nodehex, name) = line.split(b" ", 1)
         except ValueError:
             dbg(b"cannot parse entry")
             continue
         name = name.strip()
         if recode:
             name = recode(name)
         try:
             nodebin = bin(nodehex)
         except TypeError:
             dbg(b"node '%s' is not well formed" % nodehex)
             continue
 
         # update filetags
         if calcnodelines:
             # map tag name to a list of line numbers
             if name not in hextaglines:
                 hextaglines[name] = []
             hextaglines[name].append([nodehex, nline])
             continue
         # map tag name to (node, hist)
         if name not in bintaghist:
             bintaghist[name] = []
         bintaghist[name].append(nodebin)
     return bintaghist, hextaglines
 
 
 def _readtags(ui, repo, lines, fn, recode=None, calcnodelines=False):
     """Read tag definitions from a file (or any source of lines).
 
     Returns a mapping from tag name to (node, hist).
 
     "node" is the node id from the last line read for that name. "hist"
     is the list of node ids previously associated with it (in file order).
     All node ids are binary, not hex.
     """
     filetags, nodelines = _readtaghist(
         ui, repo, lines, fn, recode=recode, calcnodelines=calcnodelines
     )
     # util.sortdict().__setitem__ is much slower at replacing then inserting
     # new entries. The difference can matter if there are thousands of tags.
     # Create a new sortdict to avoid the performance penalty.
     newtags = util.sortdict()
     for tag, taghist in filetags.items():
         newtags[tag] = (taghist[-1], taghist[:-1])
     return newtags
 
 
 def _updatetags(filetags, alltags, tagtype=None, tagtypes=None):
     """Incorporate the tag info read from one file into dictionnaries
 
     The first one, 'alltags', is a "tagmaps" (see 'findglobaltags' for details).
 
     The second one, 'tagtypes', is optional and will be updated to track the
     "tagtype" of entries in the tagmaps. When set, the 'tagtype' argument also
     needs to be set."""
     if tagtype is None:
         assert tagtypes is None
 
     for name, nodehist in pycompat.iteritems(filetags):
         if name not in alltags:
             alltags[name] = nodehist
             if tagtype is not None:
                 tagtypes[name] = tagtype
             continue
 
         # we prefer alltags[name] if:
         #  it supersedes us OR
         #  mutual supersedes and it has a higher rank
         # otherwise we win because we're tip-most
         anode, ahist = nodehist
         bnode, bhist = alltags[name]
         if (
             bnode != anode
             and anode in bhist
             and (bnode not in ahist or len(bhist) > len(ahist))
         ):
             anode = bnode
         elif tagtype is not None:
             tagtypes[name] = tagtype
         ahist.extend([n for n in bhist if n not in ahist])
         alltags[name] = anode, ahist
 
 
 def _filename(repo):
     """name of a tagcache file for a given repo or repoview"""
     filename = b'tags2'
     if repo.filtername:
         filename = b'%s-%s' % (filename, repo.filtername)
     return filename
 
 
 def _readtagcache(ui, repo):
     """Read the tag cache.
 
     Returns a tuple (heads, fnodes, validinfo, cachetags, shouldwrite).
 
     If the cache is completely up-to-date, "cachetags" is a dict of the
     form returned by _readtags() and "heads", "fnodes", and "validinfo" are
     None and "shouldwrite" is False.
 
     If the cache is not up to date, "cachetags" is None. "heads" is a list
     of all heads currently in the repository, ordered from tip to oldest.
     "validinfo" is a tuple describing cache validation info. This is used
     when writing the tags cache. "fnodes" is a mapping from head to .hgtags
     filenode. "shouldwrite" is True.
 
     If the cache is not up to date, the caller is responsible for reading tag
     info from each returned head. (See findglobaltags().)
     """
     try:
         cachefile = repo.cachevfs(_filename(repo), b'r')
         # force reading the file for static-http
         cachelines = iter(cachefile)
     except IOError:
         cachefile = None
 
     cacherev = None
     cachenode = None
     cachehash = None
     if cachefile:
         try:
             validline = next(cachelines)
             validline = validline.split()
             cacherev = int(validline[0])
             cachenode = bin(validline[1])
             if len(validline) > 2:
                 cachehash = bin(validline[2])
         except Exception:
             # corruption of the cache, just recompute it.
             pass
 
     tipnode = repo.changelog.tip()
     tiprev = len(repo.changelog) - 1
 
     # Case 1 (common): tip is the same, so nothing has changed.
     # (Unchanged tip trivially means no changesets have been added.
     # But, thanks to localrepository.destroyed(), it also means none
     # have been destroyed by strip or rollback.)
     if (
         cacherev == tiprev
         and cachenode == tipnode
         and cachehash == scmutil.filteredhash(repo, tiprev)
     ):
         tags = _readtags(ui, repo, cachelines, cachefile.name)
         cachefile.close()
         return (None, None, None, tags, False)
     if cachefile:
         cachefile.close()  # ignore rest of file
 
     valid = (tiprev, tipnode, scmutil.filteredhash(repo, tiprev))
 
     repoheads = repo.heads()
     # Case 2 (uncommon): empty repo; get out quickly and don't bother
     # writing an empty cache.
     if repoheads == [repo.nullid]:
         return ([], {}, valid, {}, False)
 
     # Case 3 (uncommon): cache file missing or empty.
 
     # Case 4 (uncommon): tip rev decreased.  This should only happen
     # when we're called from localrepository.destroyed().  Refresh the
     # cache so future invocations will not see disappeared heads in the
     # cache.
 
     # Case 5 (common): tip has changed, so we've added/replaced heads.
 
     # As it happens, the code to handle cases 3, 4, 5 is the same.
 
     # N.B. in case 4 (nodes destroyed), "new head" really means "newly
     # exposed".
     if not len(repo.file(b'.hgtags')):
         # No tags have ever been committed, so we can avoid a
         # potentially expensive search.
         return ([], {}, valid, None, True)
 
     # Now we have to lookup the .hgtags filenode for every new head.
     # This is the most expensive part of finding tags, so performance
     # depends primarily on the size of newheads.  Worst case: no cache
     # file, so newheads == repoheads.
     # Reversed order helps the cache ('repoheads' is in descending order)
     cachefnode = _getfnodes(ui, repo, reversed(repoheads))
 
     # Caller has to iterate over all heads, but can use the filenodes in
     # cachefnode to get to each .hgtags revision quickly.
     return (repoheads, cachefnode, valid, None, True)
 
 
 def _getfnodes(ui, repo, nodes):
     """return .hgtags fnodes for a list of changeset nodes
 
     Return value is a {node: fnode} mapping. There will be no entry for nodes
     without a '.hgtags' file.
     """
     starttime = util.timer()
     fnodescache = hgtagsfnodescache(repo.unfiltered())
     cachefnode = {}
     validated_fnodes = set()
     unknown_entries = set()
     for node in nodes:
         fnode = fnodescache.getfnode(node)
         flog = repo.file(b'.hgtags')
         if fnode != repo.nullid:
             if fnode not in validated_fnodes:
                 if flog.hasnode(fnode):
                     validated_fnodes.add(fnode)
                 else:
                     unknown_entries.add(node)
             cachefnode[node] = fnode
 
     if unknown_entries:
         fixed_nodemap = fnodescache.refresh_invalid_nodes(unknown_entries)
         for node, fnode in pycompat.iteritems(fixed_nodemap):
             if fnode != repo.nullid:
                 cachefnode[node] = fnode
 
     fnodescache.write()
 
     duration = util.timer() - starttime
     ui.log(
         b'tagscache',
         b'%d/%d cache hits/lookups in %0.4f seconds\n',
         fnodescache.hitcount,
         fnodescache.lookupcount,
         duration,
     )
     return cachefnode
 
 
 def _writetagcache(ui, repo, valid, cachetags):
     filename = _filename(repo)
     try:
         cachefile = repo.cachevfs(filename, b'w', atomictemp=True)
     except (OSError, IOError):
         return
 
     ui.log(
         b'tagscache',
         b'writing .hg/cache/%s with %d tags\n',
         filename,
         len(cachetags),
     )
 
     if valid[2]:
         cachefile.write(
             b'%d %s %s\n' % (valid[0], hex(valid[1]), hex(valid[2]))
         )
     else:
         cachefile.write(b'%d %s\n' % (valid[0], hex(valid[1])))
 
     # Tag names in the cache are in UTF-8 -- which is the whole reason
     # we keep them in UTF-8 throughout this module.  If we converted
     # them local encoding on input, we would lose info writing them to
     # the cache.
     for (name, (node, hist)) in sorted(pycompat.iteritems(cachetags)):
         for n in hist:
             cachefile.write(b"%s %s\n" % (hex(n), name))
         cachefile.write(b"%s %s\n" % (hex(node), name))
 
     try:
         cachefile.close()
     except (OSError, IOError):
         pass
 
 
 def tag(repo, names, node, message, local, user, date, editor=False):
     """tag a revision with one or more symbolic names.
 
     names is a list of strings or, when adding a single tag, names may be a
     string.
 
     if local is True, the tags are stored in a per-repository file.
     otherwise, they are stored in the .hgtags file, and a new
     changeset is committed with the change.
 
     keyword arguments:
 
     local: whether to store tags in non-version-controlled file
     (default False)
 
     message: commit message to use if committing
 
     user: name of user to use if committing
 
     date: date tuple to use if committing"""
 
     if not local:
         m = matchmod.exact([b'.hgtags'])
         st = repo.status(match=m, unknown=True, ignored=True)
         if any(
             (
                 st.modified,
                 st.added,
                 st.removed,
                 st.deleted,
                 st.unknown,
                 st.ignored,
             )
         ):
             raise error.Abort(
                 _(b'working copy of .hgtags is changed'),
                 hint=_(b'please commit .hgtags manually'),
             )
 
     with repo.wlock():
         repo.tags()  # instantiate the cache
         _tag(repo, names, node, message, local, user, date, editor=editor)
 
 
 def _tag(
     repo, names, node, message, local, user, date, extra=None, editor=False
 ):
     if isinstance(names, bytes):
         names = (names,)
 
     branches = repo.branchmap()
     for name in names:
         repo.hook(b'pretag', throw=True, node=hex(node), tag=name, local=local)
         if name in branches:
             repo.ui.warn(
                 _(b"warning: tag %s conflicts with existing branch name\n")
                 % name
             )
 
     def writetags(fp, names, munge, prevtags):
         fp.seek(0, io.SEEK_END)
         if prevtags and not prevtags.endswith(b'\n'):
             fp.write(b'\n')
         for name in names:
             if munge:
                 m = munge(name)
             else:
                 m = name
 
             if repo._tagscache.tagtypes and name in repo._tagscache.tagtypes:
                 old = repo.tags().get(name, repo.nullid)
                 fp.write(b'%s %s\n' % (hex(old), m))
             fp.write(b'%s %s\n' % (hex(node), m))
         fp.close()
 
     prevtags = b''
     if local:
         try:
             fp = repo.vfs(b'localtags', b'r+')
         except IOError:
             fp = repo.vfs(b'localtags', b'a')
         else:
             prevtags = fp.read()
 
         # local tags are stored in the current charset
         writetags(fp, names, None, prevtags)
         for name in names:
             repo.hook(b'tag', node=hex(node), tag=name, local=local)
         return
 
     try:
         fp = repo.wvfs(b'.hgtags', b'rb+')
     except IOError as e:
         if e.errno != errno.ENOENT:
             raise
         fp = repo.wvfs(b'.hgtags', b'ab')
     else:
         prevtags = fp.read()
 
     # committed tags are stored in UTF-8
     writetags(fp, names, encoding.fromlocal, prevtags)
 
     fp.close()
 
     repo.invalidatecaches()
 
     if b'.hgtags' not in repo.dirstate:
         repo[None].add([b'.hgtags'])
 
     m = matchmod.exact([b'.hgtags'])
     tagnode = repo.commit(
         message, user, date, extra=extra, match=m, editor=editor
     )
 
     for name in names:
         repo.hook(b'tag', node=hex(node), tag=name, local=local)
 
     return tagnode
 
 
 _fnodescachefile = b'hgtagsfnodes1'
 _fnodesrecsize = 4 + 20  # changeset fragment + filenode
 _fnodesmissingrec = b'\xff' * 24
 
 
 class hgtagsfnodescache(object):
     """Persistent cache mapping revisions to .hgtags filenodes.
 
     The cache is an array of records. Each item in the array corresponds to
     a changelog revision. Values in the array contain the first 4 bytes of
     the node hash and the 20 bytes .hgtags filenode for that revision.
 
     The first 4 bytes are present as a form of verification. Repository
     stripping and rewriting may change the node at a numeric revision in the
     changelog. The changeset fragment serves as a verifier to detect
     rewriting. This logic is shared with the rev branch cache (see
     branchmap.py).
 
     The instance holds in memory the full cache content but entries are
     only parsed on read.
 
     Instances behave like lists. ``c[i]`` works where i is a rev or
     changeset node. Missing indexes are populated automatically on access.
     """
 
     def __init__(self, repo):
         assert repo.filtername is None
 
         self._repo = repo
 
         # Only for reporting purposes.
         self.lookupcount = 0
         self.hitcount = 0
 
         try:
             data = repo.cachevfs.read(_fnodescachefile)
         except (OSError, IOError):
             data = b""
         self._raw = bytearray(data)
 
         # The end state of self._raw is an array that is of the exact length
         # required to hold a record for every revision in the repository.
         # We truncate or extend the array as necessary. self._dirtyoffset is
         # defined to be the start offset at which we need to write the output
         # file. This offset is also adjusted when new entries are calculated
         # for array members.
         cllen = len(repo.changelog)
         wantedlen = cllen * _fnodesrecsize
         rawlen = len(self._raw)
 
         self._dirtyoffset = None
 
         rawlentokeep = min(
             wantedlen, (rawlen // _fnodesrecsize) * _fnodesrecsize
         )
         if rawlen > rawlentokeep:
             # There's no easy way to truncate array instances. This seems
             # slightly less evil than copying a potentially large array slice.
             for i in range(rawlen - rawlentokeep):
                 self._raw.pop()
             rawlen = len(self._raw)
             self._dirtyoffset = rawlen
         if rawlen < wantedlen:
             if self._dirtyoffset is None:
                 self._dirtyoffset = rawlen
             # TODO: zero fill entire record, because it's invalid not missing?
             self._raw.extend(b'\xff' * (wantedlen - rawlen))
 
     def getfnode(self, node, computemissing=True):
         """Obtain the filenode of the .hgtags file at a specified revision.
 
         If the value is in the cache, the entry will be validated and returned.
         Otherwise, the filenode will be computed and returned unless
         "computemissing" is False.  In that case, None will be returned if
         the entry is missing or False if the entry is invalid without
         any potentially expensive computation being performed.
 
         If an .hgtags does not exist at the specified revision, nullid is
         returned.
         """
         if node == self._repo.nullid:
             return node
 
         ctx = self._repo[node]
         rev = ctx.rev()
 
         self.lookupcount += 1
 
         offset = rev * _fnodesrecsize
         record = b'%s' % self._raw[offset : offset + _fnodesrecsize]
         properprefix = node[0:4]
 
         # Validate and return existing entry.
         if record != _fnodesmissingrec and len(record) == _fnodesrecsize:
             fileprefix = record[0:4]
 
             if fileprefix == properprefix:
                 self.hitcount += 1
                 return record[4:]
 
             # Fall through.
 
         # If we get here, the entry is either missing or invalid.
 
         if not computemissing:
             if record != _fnodesmissingrec:
                 return False
             return None
 
         fnode = self._computefnode(node)
         self._writeentry(offset, properprefix, fnode)
         return fnode
 
     def _computefnode(self, node):
         """Finds the tag filenode for a node which is missing or invalid
         in cache"""
         ctx = self._repo[node]
         rev = ctx.rev()
         fnode = None
         cl = self._repo.changelog
         p1rev, p2rev = cl._uncheckedparentrevs(rev)
         p1node = cl.node(p1rev)
         p1fnode = self.getfnode(p1node, computemissing=False)
         if p2rev != nullrev:
             # There is some no-merge changeset where p1 is null and p2 is set
             # Processing them as merge is just slower, but still gives a good
             # result.
-            p2node = cl.node(p1rev)
+            p2node = cl.node(p2rev)
             p2fnode = self.getfnode(p2node, computemissing=False)
             if p1fnode != p2fnode:
                 # we cannot rely on readfast because we don't know against what
                 # parent the readfast delta is computed
                 p1fnode = None
         if p1fnode:
             mctx = ctx.manifestctx()
             fnode = mctx.readfast().get(b'.hgtags')
             if fnode is None:
                 fnode = p1fnode
         if fnode is None:
             # Populate missing entry.
             try:
                 fnode = ctx.filenode(b'.hgtags')
             except error.LookupError:
                 # No .hgtags file on this revision.
                 fnode = self._repo.nullid
         return fnode
 
     def setfnode(self, node, fnode):
         """Set the .hgtags filenode for a given changeset."""
         assert len(fnode) == 20
         ctx = self._repo[node]
 
         # Do a lookup first to avoid writing if nothing has changed.
         if self.getfnode(ctx.node(), computemissing=False) == fnode:
             return
 
         self._writeentry(ctx.rev() * _fnodesrecsize, node[0:4], fnode)
 
     def refresh_invalid_nodes(self, nodes):
         """recomputes file nodes for a given set of nodes which has unknown
         filenodes for them in the cache
         Also updates the in-memory cache with the correct filenode.
         Caller needs to take care about calling `.write()` so that updates are
         persisted.
         Returns a map {node: recomputed fnode}
         """
         fixed_nodemap = {}
         for node in nodes:
             fnode = self._computefnode(node)
             fixed_nodemap[node] = fnode
             self.setfnode(node, fnode)
         return fixed_nodemap
 
     def _writeentry(self, offset, prefix, fnode):
         # Slices on array instances only accept other array.
         entry = bytearray(prefix + fnode)
         self._raw[offset : offset + _fnodesrecsize] = entry
         # self._dirtyoffset could be None.
         self._dirtyoffset = min(self._dirtyoffset or 0, offset or 0)
 
     def write(self):
         """Perform all necessary writes to cache file.
 
         This may no-op if no writes are needed or if a write lock could
         not be obtained.
         """
         if self._dirtyoffset is None:
             return
 
         data = self._raw[self._dirtyoffset :]
         if not data:
             return
 
         repo = self._repo
 
         try:
             lock = repo.lock(wait=False)
         except error.LockError:
             repo.ui.log(
                 b'tagscache',
                 b'not writing .hg/cache/%s because '
                 b'lock cannot be acquired\n' % _fnodescachefile,
             )
             return
 
         try:
             f = repo.cachevfs.open(_fnodescachefile, b'ab')
             try:
                 # if the file has been truncated
                 actualoffset = f.tell()
                 if actualoffset < self._dirtyoffset:
                     self._dirtyoffset = actualoffset
                     data = self._raw[self._dirtyoffset :]
                 f.seek(self._dirtyoffset)
                 f.truncate()
                 repo.ui.log(
                     b'tagscache',
                     b'writing %d bytes to cache/%s\n'
                     % (len(data), _fnodescachefile),
                 )
                 f.write(data)
                 self._dirtyoffset = None
             finally:
                 f.close()
         except (IOError, OSError) as inst:
             repo.ui.log(
                 b'tagscache',
                 b"couldn't write cache/%s: %s\n"
                 % (_fnodescachefile, stringutil.forcebytestr(inst)),
             )
         finally:
             lock.release()

tests/test-tags.t

@@ -1,935 +1,990 b''
 setup
 
   $ cat >> $HGRCPATH << EOF
   > [extensions]
   > blackbox=
   > mock=$TESTDIR/mockblackbox.py
   > [blackbox]
   > track = command, commandfinish, tagscache
   > EOF
 
 Helper functions:
 
   $ cacheexists() {
   >   [ -f .hg/cache/tags2-visible ] && echo "tag cache exists" || echo "no tag cache"
   > }
 
   $ fnodescacheexists() {
   >   [ -f .hg/cache/hgtagsfnodes1 ] && echo "fnodes cache exists" || echo "no fnodes cache"
   > }
 
   $ dumptags() {
   >     rev=$1
   >     echo "rev $rev: .hgtags:"
   >     hg cat -r$rev .hgtags
   > }
 
 # XXX need to test that the tag cache works when we strip an old head
 # and add a new one rooted off non-tip: i.e. node and rev of tip are the
 # same, but stuff has changed behind tip.
 
 Setup:
 
   $ hg init t
   $ cd t
   $ cacheexists
   no tag cache
   $ fnodescacheexists
   no fnodes cache
   $ hg id
   000000000000 tip
   $ cacheexists
   no tag cache
   $ fnodescacheexists
   no fnodes cache
   $ echo a > a
   $ hg add a
   $ hg commit -m "test"
   $ hg co
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg identify
   acb14030fe0a tip
   $ hg identify -r 'wdir()'
   acb14030fe0a tip
   $ cacheexists
   tag cache exists
 No fnodes cache because .hgtags file doesn't exist
 (this is an implementation detail)
   $ fnodescacheexists
   no fnodes cache
 
 Try corrupting the cache
 
   $ printf 'a b' > .hg/cache/tags2-visible
   $ hg identify
   acb14030fe0a tip
   $ cacheexists
   tag cache exists
   $ fnodescacheexists
   no fnodes cache
   $ hg identify
   acb14030fe0a tip
 
 Create local tag with long name:
 
   $ T=`hg identify --debug --id`
   $ hg tag -l "This is a local tag with a really long name!"
   $ hg tags
   tip                                0:acb14030fe0a
   This is a local tag with a really long name!     0:acb14030fe0a
   $ rm .hg/localtags
 
 Create a tag behind hg's back:
 
   $ echo "$T first" > .hgtags
   $ cat .hgtags
   acb14030fe0a21b60322c440ad2d20cf7685a376 first
   $ hg add .hgtags
   $ hg commit -m "add tags"
   $ hg tags
   tip                                1:b9154636be93
   first                              0:acb14030fe0a
   $ hg identify
   b9154636be93 tip
 
 We should have a fnodes cache now that we have a real tag
 The cache should have an empty entry for rev 0 and a valid entry for rev 1.
 
 
   $ fnodescacheexists
   fnodes cache exists
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=48
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
   0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|
   $ hg debugtagscache
   0 acb14030fe0a21b60322c440ad2d20cf7685a376 missing
   1 b9154636be938d3d431e75a7c906504a079bfe07 26b7b4a773e09ee3c52f510e19e05e1ff966d859
 
 Repeat with cold tag cache:
 
   $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ hg identify
   b9154636be93 tip
 
   $ fnodescacheexists
   fnodes cache exists
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=48
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
   0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|
 
 And again, but now unable to write tag cache or lock file:
 
 #if unix-permissions no-fsmonitor
 
   $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ chmod 555 .hg/cache
   $ hg identify
   b9154636be93 tip
   $ chmod 755 .hg/cache
 
 (this block should be protected by no-fsmonitor, because "chmod 555 .hg"
 makes watchman fail at accessing to files under .hg)
 
   $ chmod 555 .hg
   $ hg identify
   b9154636be93 tip
   $ chmod 755 .hg
 #endif
 
 Tag cache debug info written to blackbox log
 
   $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ hg identify
   b9154636be93 tip
   $ hg blackbox -l 6
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> writing 48 bytes to cache/hgtagsfnodes1
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> 0/2 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> blackbox -l 6
 
 Failure to acquire lock results in no write
 
   $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ echo 'foo:1' > .hg/store/lock
   $ hg identify
   b9154636be93 tip
   $ hg blackbox -l 6
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> not writing .hg/cache/hgtagsfnodes1 because lock cannot be acquired
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> 0/2 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> blackbox -l 6
 
   $ fnodescacheexists
   no fnodes cache
 
   $ rm .hg/store/lock
 
   $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ hg identify
   b9154636be93 tip
 
 Create a branch:
 
   $ echo bb > a
   $ hg status
   M a
   $ hg identify
   b9154636be93+ tip
   $ hg co first
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg id
   acb14030fe0a+ first
   $ hg id -r 'wdir()'
   acb14030fe0a+ first
   $ hg -v id
   acb14030fe0a+ first
   $ hg status
   M a
   $ echo 1 > b
   $ hg add b
   $ hg commit -m "branch"
   created new head
 
 Creating a new commit shouldn't append the .hgtags fnodes cache until
 tags info is accessed
 
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=48
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
   0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|
 
   $ hg id
   c8edf04160c7 tip
 
 First 4 bytes of record 3 are changeset fragment
 
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=72
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
   0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|
   0030: c8 ed f0 41 00 00 00 00 00 00 00 00 00 00 00 00 |...A............|
   0040: 00 00 00 00 00 00 00 00                         |........|
 
 Merge the two heads:
 
   $ hg merge 1
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg blackbox -l3
   1970-01-01 00:00:00.000 bob @c8edf04160c7f731e4589d66ab3ab3486a64ac28 (5000)> merge 1
   1970-01-01 00:00:00.000 bob @c8edf04160c7f731e4589d66ab3ab3486a64ac28+b9154636be938d3d431e75a7c906504a079bfe07 (5000)> merge 1 exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @c8edf04160c7f731e4589d66ab3ab3486a64ac28+b9154636be938d3d431e75a7c906504a079bfe07 (5000)> blackbox -l3
   $ hg id
   c8edf04160c7+b9154636be93+ tip
   $ hg status
   M .hgtags
   $ hg commit -m "merge"
 
 Create a fake head, make sure tag not visible afterwards:
 
   $ cp .hgtags tags
   $ hg tag last
   $ hg rm .hgtags
   $ hg commit -m "remove"
 
   $ mv tags .hgtags
   $ hg add .hgtags
   $ hg commit -m "readd"
   $ 
   $ hg tags
   tip                                6:35ff301afafe
   first                              0:acb14030fe0a
 
 Add invalid tags:
 
   $ echo "spam" >> .hgtags
   $ echo >> .hgtags
   $ echo "foo bar" >> .hgtags
   $ echo "a5a5 invalid" >> .hg/localtags
   $ cat .hgtags
   acb14030fe0a21b60322c440ad2d20cf7685a376 first
   spam
   
   foo bar
   $ hg commit -m "tags"
 
 Report tag parse error on other head:
 
   $ hg up 3
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo 'x y' >> .hgtags
   $ hg commit -m "head"
   created new head
 
   $ hg tags --debug
   .hgtags@75d9f02dfe28, line 2: cannot parse entry
   .hgtags@75d9f02dfe28, line 4: node 'foo' is not well formed
   .hgtags@c4be69a18c11, line 2: node 'x' is not well formed
   tip                                8:c4be69a18c11e8bc3a5fdbb576017c25f7d84663
   first                              0:acb14030fe0a21b60322c440ad2d20cf7685a376
   $ hg tip
   changeset:   8:c4be69a18c11
   tag:         tip
   parent:      3:ac5e980c4dc0
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     head
   
 
 Test tag precedence rules:
 
   $ cd ..
   $ hg init t2
   $ cd t2
   $ echo foo > foo
   $ hg add foo
   $ hg ci -m 'add foo'      # rev 0
   $ hg tag bar              # rev 1
   $ echo >> foo
   $ hg ci -m 'change foo 1' # rev 2
   $ hg up -C 1
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg tag -r 1 -f bar      # rev 3
   $ hg up -C 1
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo >> foo
   $ hg ci -m 'change foo 2' # rev 4
   created new head
   $ hg tags
   tip                                4:0c192d7d5e6b
   bar                                1:78391a272241
 
 Repeat in case of cache effects:
 
   $ hg tags
   tip                                4:0c192d7d5e6b
   bar                                1:78391a272241
 
 Detailed dump of tag info:
 
   $ hg heads -q             # expect 4, 3, 2
   4:0c192d7d5e6b
   3:6fa450212aeb
   2:7a94127795a3
   $ dumptags 2
   rev 2: .hgtags:
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   $ dumptags 3
   rev 3: .hgtags:
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   78391a272241d70354aa14c874552cad6b51bb42 bar
   $ dumptags 4
   rev 4: .hgtags:
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
 
 Dump cache:
 
   $ cat .hg/cache/tags2-visible
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   78391a272241d70354aa14c874552cad6b51bb42 bar
 
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=120
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0030: 7a 94 12 77 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |z..w.....1....B(|
   0040: 78 ee 5a 2d ad bc 94 3d 6f a4 50 21 7d 3b 71 8c |x.Z-...=o.P!};q.|
   0050: 96 4e f3 7b 89 e5 50 eb da fd 57 89 e7 6c e1 b0 |.N.{..P...W..l..|
   0060: 0c 19 2d 7d 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |..-}.....1....B(|
   0070: 78 ee 5a 2d ad bc 94 3d                         |x.Z-...=|
 
 Corrupt the .hgtags fnodes cache
 Extra junk data at the end should get overwritten on next cache update
 
   $ echo extra >> .hg/cache/hgtagsfnodes1
   $ echo dummy1 > foo
   $ hg commit -m throwaway1
 
   $ hg tags
   tip                                5:8dbfe60eff30
   bar                                1:78391a272241
 
   $ hg blackbox -l 6
   1970-01-01 00:00:00.000 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags
   1970-01-01 00:00:00.000 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing 24 bytes to cache/hgtagsfnodes1
   1970-01-01 00:00:00.000 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> 3/4 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> blackbox -l 6
 
 On junk data + missing cache entries, hg also overwrites the junk.
 
   $ rm -f .hg/cache/tags2-visible
   >>> import os
   >>> with open(".hg/cache/hgtagsfnodes1", "ab+") as fp:
   ...     fp.seek(-10, os.SEEK_END) and None
   ...     fp.truncate() and None
 
   $ hg debugtagscache | tail -2
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 missing
   $ hg tags
   tip                                5:8dbfe60eff30
   bar                                1:78391a272241
   $ hg debugtagscache | tail -2
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8af31de17fab7422878ee5a2dadbc943d
 
 If the 4 bytes of node hash for a record don't match an existing node, the entry
 is flagged as invalid.
 
   >>> import os
   >>> with open(".hg/cache/hgtagsfnodes1", "rb+") as fp:
   ...     fp.seek(-24, os.SEEK_END) and None
   ...     fp.write(b'\xde\xad') and None
 
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=144
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0030: 7a 94 12 77 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |z..w.....1....B(|
   0040: 78 ee 5a 2d ad bc 94 3d 6f a4 50 21 7d 3b 71 8c |x.Z-...=o.P!};q.|
   0050: 96 4e f3 7b 89 e5 50 eb da fd 57 89 e7 6c e1 b0 |.N.{..P...W..l..|
   0060: 0c 19 2d 7d 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |..-}.....1....B(|
   0070: 78 ee 5a 2d ad bc 94 3d de ad e6 0e 0c 04 f2 a8 |x.Z-...=........|
   0080: af 31 de 17 fa b7 42 28 78 ee 5a 2d ad bc 94 3d |.1....B(x.Z-...=|
 
   $ hg debugtagscache | tail -2
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 invalid
 
   $ hg tags
   tip                                5:8dbfe60eff30
   bar                                1:78391a272241
 
 BUG: If the filenode part of an entry in hgtagsfnodes is corrupt and
 tags2-visible is missing, `hg tags` aborts.  Corrupting the leading 4 bytes of
 node hash (as above) doesn't seem to trigger the issue.  Also note that the
 debug command hides the corruption, both with and without tags2-visible.
 
   $ mv .hg/cache/hgtagsfnodes1 .hg/cache/hgtagsfnodes1.bak
   $ hg debugupdatecaches
 
   >>> import os
   >>> with open(".hg/cache/hgtagsfnodes1", "rb+") as fp:
   ...     fp.seek(-16, os.SEEK_END) and None
   ...     fp.write(b'\xde\xad') and None
 
   $ f --size --hexdump .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=144
   0000: bb d1 79 df 00 00 00 00 00 00 00 00 00 00 00 00 |..y.............|
   0010: 00 00 00 00 00 00 00 00 78 39 1a 27 0c 04 f2 a8 |........x9.'....|
   0020: af 31 de 17 fa b7 42 28 78 ee 5a 2d ad bc 94 3d |.1....B(x.Z-...=|
   0030: 7a 94 12 77 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |z..w.....1....B(|
   0040: 78 ee 5a 2d ad bc 94 3d 6f a4 50 21 7d 3b 71 8c |x.Z-...=o.P!};q.|
   0050: 96 4e f3 7b 89 e5 50 eb da fd 57 89 e7 6c e1 b0 |.N.{..P...W..l..|
   0060: 0c 19 2d 7d 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |..-}.....1....B(|
   0070: 78 ee 5a 2d ad bc 94 3d 8d bf e6 0e 0c 04 f2 a8 |x.Z-...=........|
   0080: de ad de 17 fa b7 42 28 78 ee 5a 2d ad bc 94 3d |......B(x.Z-...=|
 
   $ hg debugtagscache | tail -2
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8deadde17fab7422878ee5a2dadbc943d (unknown node)
 
   $ rm -f .hg/cache/tags2-visible
   $ hg debugtagscache | tail -2
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a 0c04f2a8af31de17fab7422878ee5a2dadbc943d
   5 8dbfe60eff306a54259cfe007db9e330e7ecf866 0c04f2a8deadde17fab7422878ee5a2dadbc943d (unknown node)
 
   $ hg tags
   tip                                5:8dbfe60eff30
   bar                                1:78391a272241
 
 BUG: Unless this file is restored, the `hg tags` in the next unix-permissions
 conditional will fail: "abort: data/.hgtags.i@0c04f2a8dead: no match found"
 
   $ mv .hg/cache/hgtagsfnodes1.bak .hg/cache/hgtagsfnodes1
 
 #if unix-permissions no-root
 Errors writing to .hgtags fnodes cache are silently ignored
 
   $ echo dummy2 > foo
   $ hg commit -m throwaway2
 
   $ chmod a-w .hg/cache/hgtagsfnodes1
   $ rm -f .hg/cache/tags2-visible
 
   $ hg tags
   tip                                6:b968051b5cf3
   bar                                1:78391a272241
 
   $ hg blackbox -l 6
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> couldn't write cache/hgtagsfnodes1: [Errno *] * (glob)
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> 2/4 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> blackbox -l 6
 
   $ chmod a+w .hg/cache/hgtagsfnodes1
 
   $ rm -f .hg/cache/tags2-visible
   $ hg tags
   tip                                6:b968051b5cf3
   bar                                1:78391a272241
 
   $ hg blackbox -l 6
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> writing 24 bytes to cache/hgtagsfnodes1
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> 2/4 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> blackbox -l 6
 
   $ f --size .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=168
 
   $ hg -q --config extensions.strip= strip -r 6 --no-backup
 #endif
 
 Stripping doesn't truncate the tags cache until new data is available
 
   $ rm -f .hg/cache/hgtagsfnodes1 .hg/cache/tags2-visible
   $ hg tags
   tip                                5:8dbfe60eff30
   bar                                1:78391a272241
 
   $ f --size .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=144
 
   $ hg -q --config extensions.strip= strip -r 5 --no-backup
   $ hg tags
   tip                                4:0c192d7d5e6b
   bar                                1:78391a272241
 
   $ hg blackbox -l 5
   1970-01-01 00:00:00.000 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> writing 24 bytes to cache/hgtagsfnodes1
   1970-01-01 00:00:00.000 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> 2/4 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> tags exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> blackbox -l 5
 
   $ f --size .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=120
 
   $ echo dummy > foo
   $ hg commit -m throwaway3
 
   $ hg tags
   tip                                5:035f65efb448
   bar                                1:78391a272241
 
   $ hg blackbox -l 6
   1970-01-01 00:00:00.000 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> tags
   1970-01-01 00:00:00.000 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> writing 24 bytes to cache/hgtagsfnodes1
   1970-01-01 00:00:00.000 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> 3/4 cache hits/lookups in * seconds (glob)
   1970-01-01 00:00:00.000 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> writing .hg/cache/tags2-visible with 1 tags
   1970-01-01 00:00:00.000 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> tags exited 0 after * seconds (glob)
   1970-01-01 00:00:00.000 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> blackbox -l 6
   $ f --size .hg/cache/hgtagsfnodes1
   .hg/cache/hgtagsfnodes1: size=144
 
   $ hg -q --config extensions.strip= strip -r 5 --no-backup
 
 Test tag removal:
 
   $ hg tag --remove bar     # rev 5
   $ hg tip -vp
   changeset:   5:5f6e8655b1c7
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   files:       .hgtags
   description:
   Removed tag bar
   
   
   diff -r 0c192d7d5e6b -r 5f6e8655b1c7 .hgtags
   --- a/.hgtags	Thu Jan 01 00:00:00 1970 +0000
   +++ b/.hgtags	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
    bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   +78391a272241d70354aa14c874552cad6b51bb42 bar
   +0000000000000000000000000000000000000000 bar
   
   $ hg tags
   tip                                5:5f6e8655b1c7
   $ hg tags                 # again, try to expose cache bugs
   tip                                5:5f6e8655b1c7
 
 Remove nonexistent tag:
 
   $ hg tag --remove foobar
   abort: tag 'foobar' does not exist
   [10]
   $ hg tip
   changeset:   5:5f6e8655b1c7
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Removed tag bar
   
 
 Undo a tag with rollback:
 
   $ hg rollback             # destroy rev 5 (restore bar)
   repository tip rolled back to revision 4 (undo commit)
   working directory now based on revision 4
   $ hg tags
   tip                                4:0c192d7d5e6b
   bar                                1:78391a272241
   $ hg tags
   tip                                4:0c192d7d5e6b
   bar                                1:78391a272241
 
 Test tag rank:
 
   $ cd ..
   $ hg init t3
   $ cd t3
   $ echo foo > foo
   $ hg add foo
   $ hg ci -m 'add foo'       # rev 0
   $ hg tag -f bar            # rev 1 bar -> 0
   $ hg tag -f bar            # rev 2 bar -> 1
   $ hg tag -fr 0 bar         # rev 3 bar -> 0
   $ hg tag -fr 1 bar         # rev 4 bar -> 1
   $ hg tag -fr 0 bar         # rev 5 bar -> 0
   $ hg tags
   tip                                5:85f05169d91d
   bar                                0:bbd179dfa0a7
   $ hg co 3
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo barbar > foo
   $ hg ci -m 'change foo'    # rev 6
   created new head
   $ hg tags
   tip                                6:735c3ca72986
   bar                                0:bbd179dfa0a7
 
 Don't allow moving tag without -f:
 
   $ hg tag -r 3 bar
   abort: tag 'bar' already exists (use -f to force)
   [10]
   $ hg tags
   tip                                6:735c3ca72986
   bar                                0:bbd179dfa0a7
 
 Strip 1: expose an old head:
 
   $ hg --config extensions.mq= strip 5
   saved backup bundle to $TESTTMP/t3/.hg/strip-backup/*-backup.hg (glob)
   $ hg tags                  # partly stale cache
   tip                                5:735c3ca72986
   bar                                1:78391a272241
   $ hg tags                  # up-to-date cache
   tip                                5:735c3ca72986
   bar                                1:78391a272241
 
 Strip 2: destroy whole branch, no old head exposed
 
   $ hg --config extensions.mq= strip 4
   saved backup bundle to $TESTTMP/t3/.hg/strip-backup/*-backup.hg (glob)
   $ hg tags                  # partly stale
   tip                                4:735c3ca72986
   bar                                0:bbd179dfa0a7
   $ rm -f .hg/cache/tags2-visible
   $ hg tags                  # cold cache
   tip                                4:735c3ca72986
   bar                                0:bbd179dfa0a7
 
 Test tag rank with 3 heads:
 
   $ cd ..
   $ hg init t4
   $ cd t4
   $ echo foo > foo
   $ hg add
   adding foo
   $ hg ci -m 'add foo'                 # rev 0
   $ hg tag bar                         # rev 1 bar -> 0
   $ hg tag -f bar                      # rev 2 bar -> 1
   $ hg up -qC 0
   $ hg tag -fr 2 bar                   # rev 3 bar -> 2
   $ hg tags
   tip                                3:197c21bbbf2c
   bar                                2:6fa450212aeb
   $ hg up -qC 0
   $ hg tag -m 'retag rev 0' -fr 0 bar  # rev 4 bar -> 0, but bar stays at 2
 
 Bar should still point to rev 2:
 
   $ hg tags
   tip                                4:3b4b14ed0202
   bar                                2:6fa450212aeb
 
 Test that removing global/local tags does not get confused when trying
 to remove a tag of type X which actually only exists as a type Y:
 
   $ cd ..
   $ hg init t5
   $ cd t5
   $ echo foo > foo
   $ hg add
   adding foo
   $ hg ci -m 'add foo'                 # rev 0
 
   $ hg tag -r 0 -l localtag
   $ hg tag --remove localtag
   abort: tag 'localtag' is not a global tag
   [10]
   $ 
   $ hg tag -r 0 globaltag
   $ hg tag --remove -l globaltag
   abort: tag 'globaltag' is not a local tag
   [10]
   $ hg tags -v
   tip                                1:a0b6fe111088
   localtag                           0:bbd179dfa0a7 local
   globaltag                          0:bbd179dfa0a7
 
 Templated output:
 
  (immediate values)
 
   $ hg tags -T '{pad(tag, 9)} {rev}:{node} ({type})\n'
   tip       1:a0b6fe111088c8c29567d3876cc466aa02927cae ()
   localtag  0:bbd179dfa0a71671c253b3ae0aa1513b60d199fa (local)
   globaltag 0:bbd179dfa0a71671c253b3ae0aa1513b60d199fa ()
 
  (ctx/revcache dependent)
 
   $ hg tags -T '{pad(tag, 9)} {rev} {file_adds}\n'
   tip       1 .hgtags
   localtag  0 foo
   globaltag 0 foo
 
   $ hg tags -T '{pad(tag, 9)} {rev}:{node|shortest}\n'
   tip       1:a0b6
   localtag  0:bbd1
   globaltag 0:bbd1
 
 Test for issue3911
 
   $ hg tag -r 0 -l localtag2
   $ hg tag -l --remove localtag2
   $ hg tags -v
   tip                                1:a0b6fe111088
   localtag                           0:bbd179dfa0a7 local
   globaltag                          0:bbd179dfa0a7
 
   $ hg tag -r 1 -f localtag
   $ hg tags -v
   tip                                2:5c70a037bb37
   localtag                           1:a0b6fe111088
   globaltag                          0:bbd179dfa0a7
 
   $ hg tags -v
   tip                                2:5c70a037bb37
   localtag                           1:a0b6fe111088
   globaltag                          0:bbd179dfa0a7
 
   $ hg tag -r 1 localtag2
   $ hg tags -v
   tip                                3:bbfb8cd42be2
   localtag2                          1:a0b6fe111088
   localtag                           1:a0b6fe111088
   globaltag                          0:bbd179dfa0a7
 
   $ hg tags -v
   tip                                3:bbfb8cd42be2
   localtag2                          1:a0b6fe111088
   localtag                           1:a0b6fe111088
   globaltag                          0:bbd179dfa0a7
 
   $ cd ..
 
 Create a repository with tags data to test .hgtags fnodes transfer
 
   $ hg init tagsserver
   $ cd tagsserver
   $ touch foo
   $ hg -q commit -A -m initial
   $ hg tag -m 'tag 0.1' 0.1
   $ echo second > foo
   $ hg commit -m second
   $ hg tag -m 'tag 0.2' 0.2
   $ hg tags
   tip                                3:40f0358cb314
   0.2                                2:f63cc8fe54e4
   0.1                                0:96ee1d7354c4
   $ cd ..
 
 Cloning should pull down hgtags fnodes mappings and write the cache file
 
   $ hg clone --pull tagsserver tagsclient
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 4 changesets with 4 changes to 2 files
   new changesets 96ee1d7354c4:40f0358cb314
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 Missing tags2* files means the cache wasn't written through the normal mechanism.
 
   $ ls tagsclient/.hg/cache
   branch2-base
   branch2-immutable
   branch2-served
   branch2-served.hidden
   branch2-visible
   branch2-visible-hidden
   hgtagsfnodes1
   rbc-names-v1
   rbc-revs-v1
   tags2
   tags2-served
 
 Cache should contain the head only, even though other nodes have tags data
 
   $ f --size --hexdump tagsclient/.hg/cache/hgtagsfnodes1
   tagsclient/.hg/cache/hgtagsfnodes1: size=96
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0040: ff ff ff ff ff ff ff ff 40 f0 35 8c 19 e0 a7 d3 |........@.5.....|
   0050: 8a 5c 6a 82 4d cf fb a5 87 d0 2f a3 1e 4f 2f 8a |.\j.M...../..O/.|
 
 Running hg tags should produce tags2* file and not change cache
 
   $ hg -R tagsclient tags
   tip                                3:40f0358cb314
   0.2                                2:f63cc8fe54e4
   0.1                                0:96ee1d7354c4
 
   $ ls tagsclient/.hg/cache
   branch2-base
   branch2-immutable
   branch2-served
   branch2-served.hidden
   branch2-visible
   branch2-visible-hidden
   hgtagsfnodes1
   rbc-names-v1
   rbc-revs-v1
   tags2
   tags2-served
   tags2-visible
 
   $ f --size --hexdump tagsclient/.hg/cache/hgtagsfnodes1
   tagsclient/.hg/cache/hgtagsfnodes1: size=96
   0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
   0040: ff ff ff ff ff ff ff ff 40 f0 35 8c 19 e0 a7 d3 |........@.5.....|
   0050: 8a 5c 6a 82 4d cf fb a5 87 d0 2f a3 1e 4f 2f 8a |.\j.M...../..O/.|
 
 Check that the bundle includes cache data
 
   $ hg -R tagsclient bundle --all ./test-cache-in-bundle-all-rev.hg
   4 changesets found
   $ hg debugbundle ./test-cache-in-bundle-all-rev.hg
   Stream params: {Compression: BZ}
   changegroup -- {nbchanges: 4, version: 02} (mandatory: True)
       96ee1d7354c4ad7372047672c36a1f561e3a6a4c
       c4dab0c2fd337eb9191f80c3024830a4889a8f34
       f63cc8fe54e4d326f8d692805d70e092f851ddb1
       40f0358cb314c824a5929ee527308d90e023bc10
   hgtagsfnodes -- {} (mandatory: True)
   cache:rev-branch-cache -- {} (mandatory: False)
 
 Check that local clone includes cache data
 
   $ hg clone tagsclient tags-local-clone
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ (cd tags-local-clone/.hg/cache/; ls -1 tag*)
   tags2
   tags2-served
   tags2-visible
 
 Avoid writing logs on trying to delete an already deleted tag
   $ hg init issue5752
   $ cd issue5752
   $ echo > a
   $ hg commit -Am 'add a'
   adding a
   $ hg tag a
   $ hg tags
   tip                                1:bd7ee4f3939b
   a                                  0:a8a82d372bb3
   $ hg log
   changeset:   1:bd7ee4f3939b
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Added tag a for changeset a8a82d372bb3
   
   changeset:   0:a8a82d372bb3
   tag:         a
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     add a
   
   $ hg tag --remove a
   $ hg log
   changeset:   2:e7feacc7ec9e
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Removed tag a
   
   changeset:   1:bd7ee4f3939b
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Added tag a for changeset a8a82d372bb3
   
   changeset:   0:a8a82d372bb3
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     add a
   
   $ hg tag --remove a
   abort: tag 'a' is already removed
   [10]
   $ hg log
   changeset:   2:e7feacc7ec9e
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Removed tag a
   
   changeset:   1:bd7ee4f3939b
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Added tag a for changeset a8a82d372bb3
   
   changeset:   0:a8a82d372bb3
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     add a
   
   $ cat .hgtags
   a8a82d372bb35b42ff736e74f07c23bcd99c371f a
   a8a82d372bb35b42ff736e74f07c23bcd99c371f a
   0000000000000000000000000000000000000000 a
+
+  $ cd ..
+
+.hgtags fnode should be properly resolved at merge revision (issue6673)
+
+  $ hg init issue6673
+  $ cd issue6673
+
+  $ touch a
+  $ hg ci -qAm a
+  $ hg branch -q stable
+  $ hg ci -m branch
+
+  $ hg up -q default
+  $ hg merge -q stable
+  $ hg ci -m merge
+
+ add tag to stable branch:
+
+  $ hg up -q stable
+  $ echo a >> a
+  $ hg ci -m a
+  $ hg tag whatever
+  $ hg log -GT'{rev} {tags}\n'
+  @  4 tip
+  |
+  o  3 whatever
+  |
+  | o  2
+  |/|
+  o |  1
+  |/
+  o  0
+  
+
+ merge tagged stable into default:
+
+  $ hg up -q default
+  $ hg merge -q  stable
+  $ hg ci -m merge
+  $ hg log -GT'{rev} {tags}\n'
+  @    5 tip
+  |\
+  | o  4
+  | |
+  | o  3 whatever
+  | |
+  o |  2
+  |\|
+  | o  1
+  |/
+  o  0
+  
+
+  $ cd ..