branchmap: acquires lock before writting the rev branch cache

We now attempt to acquire a lock and write the branch cache within that lock.
This would prevent cache corruption when multiple processes try to write the cache
at the same time.

mercurial/branchmap.py

@@ -1,523 +1,532
 # branchmap.py - logic to computes, maintain and stores branchmap for local repo
 #
 # Copyright 2005-2007 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 array
 import struct
 import time
 
 from .node import (
     bin,
     hex,
     nullid,
     nullrev,
 )
 from . import (
     encoding,
     error,
     scmutil,
 )
 
 array = array.array
 calcsize = struct.calcsize
 pack = struct.pack
 unpack = struct.unpack
 
 def _filename(repo):
     """name of a branchcache file for a given repo or repoview"""
     filename = "cache/branch2"
     if repo.filtername:
         filename = '%s-%s' % (filename, repo.filtername)
     return filename
 
 def read(repo):
     try:
         f = repo.vfs(_filename(repo))
         lines = f.read().split('\n')
         f.close()
     except (IOError, OSError):
         return None
 
     try:
         cachekey = lines.pop(0).split(" ", 2)
         last, lrev = cachekey[:2]
         last, lrev = bin(last), int(lrev)
         filteredhash = None
         if len(cachekey) > 2:
             filteredhash = bin(cachekey[2])
         partial = branchcache(tipnode=last, tiprev=lrev,
                               filteredhash=filteredhash)
         if not partial.validfor(repo):
             # invalidate the cache
             raise ValueError('tip differs')
         cl = repo.changelog
         for l in lines:
             if not l:
                 continue
             node, state, label = l.split(" ", 2)
             if state not in 'oc':
                 raise ValueError('invalid branch state')
             label = encoding.tolocal(label.strip())
             node = bin(node)
             if not cl.hasnode(node):
                 raise ValueError('node %s does not exist' % hex(node))
             partial.setdefault(label, []).append(node)
             if state == 'c':
                 partial._closednodes.add(node)
     except KeyboardInterrupt:
         raise
     except Exception as inst:
         if repo.ui.debugflag:
             msg = 'invalid branchheads cache'
             if repo.filtername is not None:
                 msg += ' (%s)' % repo.filtername
             msg += ': %s\n'
             repo.ui.debug(msg % inst)
         partial = None
     return partial
 
 ### Nearest subset relation
 # Nearest subset of filter X is a filter Y so that:
 # * Y is included in X,
 # * X - Y is as small as possible.
 # This create and ordering used for branchmap purpose.
 # the ordering may be partial
 subsettable = {None: 'visible',
                'visible': 'served',
                'served': 'immutable',
                'immutable': 'base'}
 
 def updatecache(repo):
     cl = repo.changelog
     filtername = repo.filtername
     partial = repo._branchcaches.get(filtername)
 
     revs = []
     if partial is None or not partial.validfor(repo):
         partial = read(repo)
         if partial is None:
             subsetname = subsettable.get(filtername)
             if subsetname is None:
                 partial = branchcache()
             else:
                 subset = repo.filtered(subsetname)
                 partial = subset.branchmap().copy()
                 extrarevs = subset.changelog.filteredrevs - cl.filteredrevs
                 revs.extend(r for  r in extrarevs if r <= partial.tiprev)
     revs.extend(cl.revs(start=partial.tiprev + 1))
     if revs:
         partial.update(repo, revs)
         partial.write(repo)
 
     assert partial.validfor(repo), filtername
     repo._branchcaches[repo.filtername] = partial
 
 def replacecache(repo, bm):
     """Replace the branchmap cache for a repo with a branch mapping.
 
     This is likely only called during clone with a branch map from a remote.
     """
     rbheads = []
     closed = []
     for bheads in bm.itervalues():
         rbheads.extend(bheads)
         for h in bheads:
             r = repo.changelog.rev(h)
             b, c = repo.changelog.branchinfo(r)
             if c:
                 closed.append(h)
 
     if rbheads:
         rtiprev = max((int(repo.changelog.rev(node))
                 for node in rbheads))
         cache = branchcache(bm,
                             repo[rtiprev].node(),
                             rtiprev,
                             closednodes=closed)
 
         # Try to stick it as low as possible
         # filter above served are unlikely to be fetch from a clone
         for candidate in ('base', 'immutable', 'served'):
             rview = repo.filtered(candidate)
             if cache.validfor(rview):
                 repo._branchcaches[candidate] = cache
                 cache.write(rview)
                 break
 
 class branchcache(dict):
     """A dict like object that hold branches heads cache.
 
     This cache is used to avoid costly computations to determine all the
     branch heads of a repo.
 
     The cache is serialized on disk in the following format:
 
     <tip hex node> <tip rev number> [optional filtered repo hex hash]
     <branch head hex node> <open/closed state> <branch name>
     <branch head hex node> <open/closed state> <branch name>
     ...
 
     The first line is used to check if the cache is still valid. If the
     branch cache is for a filtered repo view, an optional third hash is
     included that hashes the hashes of all filtered revisions.
 
     The open/closed state is represented by a single letter 'o' or 'c'.
     This field can be used to avoid changelog reads when determining if a
     branch head closes a branch or not.
     """
 
     def __init__(self, entries=(), tipnode=nullid, tiprev=nullrev,
                  filteredhash=None, closednodes=None):
         super(branchcache, self).__init__(entries)
         self.tipnode = tipnode
         self.tiprev = tiprev
         self.filteredhash = filteredhash
         # closednodes is a set of nodes that close their branch. If the branch
         # cache has been updated, it may contain nodes that are no longer
         # heads.
         if closednodes is None:
             self._closednodes = set()
         else:
             self._closednodes = closednodes
 
     def validfor(self, repo):
         """Is the cache content valid regarding a repo
 
         - False when cached tipnode is unknown or if we detect a strip.
         - True when cache is up to date or a subset of current repo."""
         try:
             return ((self.tipnode == repo.changelog.node(self.tiprev))
                     and (self.filteredhash == \
                          scmutil.filteredhash(repo, self.tiprev)))
         except IndexError:
             return False
 
     def _branchtip(self, heads):
         '''Return tuple with last open head in heads and false,
         otherwise return last closed head and true.'''
         tip = heads[-1]
         closed = True
         for h in reversed(heads):
             if h not in self._closednodes:
                 tip = h
                 closed = False
                 break
         return tip, closed
 
     def branchtip(self, branch):
         '''Return the tipmost open head on branch head, otherwise return the
         tipmost closed head on branch.
         Raise KeyError for unknown branch.'''
         return self._branchtip(self[branch])[0]
 
     def branchheads(self, branch, closed=False):
         heads = self[branch]
         if not closed:
             heads = [h for h in heads if h not in self._closednodes]
         return heads
 
     def iterbranches(self):
         for bn, heads in self.iteritems():
             yield (bn, heads) + self._branchtip(heads)
 
     def copy(self):
         """return an deep copy of the branchcache object"""
         return branchcache(self, self.tipnode, self.tiprev, self.filteredhash,
                            self._closednodes)
 
     def write(self, repo):
         try:
             f = repo.vfs(_filename(repo), "w", atomictemp=True)
             cachekey = [hex(self.tipnode), str(self.tiprev)]
             if self.filteredhash is not None:
                 cachekey.append(hex(self.filteredhash))
             f.write(" ".join(cachekey) + '\n')
             nodecount = 0
             for label, nodes in sorted(self.iteritems()):
                 for node in nodes:
                     nodecount += 1
                     if node in self._closednodes:
                         state = 'c'
                     else:
                         state = 'o'
                     f.write("%s %s %s\n" % (hex(node), state,
                                             encoding.fromlocal(label)))
             f.close()
             repo.ui.log('branchcache',
                         'wrote %s branch cache with %d labels and %d nodes\n',
                         repo.filtername, len(self), nodecount)
         except (IOError, OSError, error.Abort) as inst:
             repo.ui.debug("couldn't write branch cache: %s\n" % inst)
             # Abort may be raise by read only opener
             pass
 
     def update(self, repo, revgen):
         """Given a branchhead cache, self, that may have extra nodes or be
         missing heads, and a generator of nodes that are strictly a superset of
         heads missing, this function updates self to be correct.
         """
         starttime = time.time()
         cl = repo.changelog
         # collect new branch entries
         newbranches = {}
         getbranchinfo = repo.revbranchcache().branchinfo
         for r in revgen:
             branch, closesbranch = getbranchinfo(r)
             newbranches.setdefault(branch, []).append(r)
             if closesbranch:
                 self._closednodes.add(cl.node(r))
 
         # fetch current topological heads to speed up filtering
         topoheads = set(cl.headrevs())
 
         # if older branchheads are reachable from new ones, they aren't
         # really branchheads. Note checking parents is insufficient:
         # 1 (branch a) -> 2 (branch b) -> 3 (branch a)
         for branch, newheadrevs in newbranches.iteritems():
             bheads = self.setdefault(branch, [])
             bheadset = set(cl.rev(node) for node in bheads)
 
             # This have been tested True on all internal usage of this function.
             # run it again in case of doubt
             # assert not (set(bheadrevs) & set(newheadrevs))
             newheadrevs.sort()
             bheadset.update(newheadrevs)
 
             # This prunes out two kinds of heads - heads that are superseded by
             # a head in newheadrevs, and newheadrevs that are not heads because
             # an existing head is their descendant.
             uncertain = bheadset - topoheads
             if uncertain:
                 floorrev = min(uncertain)
                 ancestors = set(cl.ancestors(newheadrevs, floorrev))
                 bheadset -= ancestors
             bheadrevs = sorted(bheadset)
             self[branch] = [cl.node(rev) for rev in bheadrevs]
             tiprev = bheadrevs[-1]
             if tiprev > self.tiprev:
                 self.tipnode = cl.node(tiprev)
                 self.tiprev = tiprev
 
         if not self.validfor(repo):
             # cache key are not valid anymore
             self.tipnode = nullid
             self.tiprev = nullrev
             for heads in self.values():
                 tiprev = max(cl.rev(node) for node in heads)
                 if tiprev > self.tiprev:
                     self.tipnode = cl.node(tiprev)
                     self.tiprev = tiprev
         self.filteredhash = scmutil.filteredhash(repo, self.tiprev)
 
         duration = time.time() - starttime
         repo.ui.log('branchcache', 'updated %s branch cache in %.4f seconds\n',
                     repo.filtername, duration)
 
 # Revision branch info cache
 
 _rbcversion = '-v1'
 _rbcnames = 'cache/rbc-names' + _rbcversion
 _rbcrevs = 'cache/rbc-revs' + _rbcversion
 # [4 byte hash prefix][4 byte branch name number with sign bit indicating open]
 _rbcrecfmt = '>4sI'
 _rbcrecsize = calcsize(_rbcrecfmt)
 _rbcnodelen = 4
 _rbcbranchidxmask = 0x7fffffff
 _rbccloseflag = 0x80000000
 
 class revbranchcache(object):
     """Persistent cache, mapping from revision number to branch name and close.
     This is a low level cache, independent of filtering.
 
     Branch names are stored in rbc-names in internal encoding separated by 0.
     rbc-names is append-only, and each branch name is only stored once and will
     thus have a unique index.
 
     The branch info for each revision is stored in rbc-revs as constant size
     records. The whole file is read into memory, but it is only 'parsed' on
     demand. The file is usually append-only but will be truncated if repo
     modification is detected.
     The record for each revision contains the first 4 bytes of the
     corresponding node hash, and the record is only used if it still matches.
     Even a completely trashed rbc-revs fill thus still give the right result
     while converging towards full recovery ... assuming no incorrectly matching
     node hashes.
     The record also contains 4 bytes where 31 bits contains the index of the
     branch and the last bit indicate that it is a branch close commit.
     The usage pattern for rbc-revs is thus somewhat similar to 00changelog.i
     and will grow with it but be 1/8th of its size.
     """
 
     def __init__(self, repo, readonly=True):
         assert repo.filtername is None
         self._repo = repo
         self._names = [] # branch names in local encoding with static index
         self._rbcrevs = array('c') # structs of type _rbcrecfmt
         self._rbcsnameslen = 0 # length of names read at _rbcsnameslen
         try:
             bndata = repo.vfs.read(_rbcnames)
             self._rbcsnameslen = len(bndata) # for verification before writing
             self._names = [encoding.tolocal(bn) for bn in bndata.split('\0')]
         except (IOError, OSError):
             if readonly:
                 # don't try to use cache - fall back to the slow path
                 self.branchinfo = self._branchinfo
 
         if self._names:
             try:
                 data = repo.vfs.read(_rbcrevs)
                 self._rbcrevs.fromstring(data)
             except (IOError, OSError) as inst:
                 repo.ui.debug("couldn't read revision branch cache: %s\n" %
                               inst)
         # remember number of good records on disk
         self._rbcrevslen = min(len(self._rbcrevs) // _rbcrecsize,
                                len(repo.changelog))
         if self._rbcrevslen == 0:
             self._names = []
         self._rbcnamescount = len(self._names) # number of names read at
                                                # _rbcsnameslen
         self._namesreverse = dict((b, r) for r, b in enumerate(self._names))
 
     def _clear(self):
         self._rbcsnameslen = 0
         del self._names[:]
         self._rbcnamescount = 0
         self._namesreverse.clear()
         self._rbcrevslen = len(self._repo.changelog)
         self._rbcrevs = array('c')
         self._rbcrevs.fromstring('\0' * (self._rbcrevslen * _rbcrecsize))
 
     def branchinfo(self, rev):
         """Return branch name and close flag for rev, using and updating
         persistent cache."""
         changelog = self._repo.changelog
         rbcrevidx = rev * _rbcrecsize
 
         # avoid negative index, changelog.read(nullrev) is fast without cache
         if rev == nullrev:
             return changelog.branchinfo(rev)
 
         # if requested rev isn't allocated, grow and cache the rev info
         if len(self._rbcrevs) < rbcrevidx + _rbcrecsize:
             return self._branchinfo(rev)
 
         # fast path: extract data from cache, use it if node is matching
         reponode = changelog.node(rev)[:_rbcnodelen]
         cachenode, branchidx = unpack(
             _rbcrecfmt, buffer(self._rbcrevs, rbcrevidx, _rbcrecsize))
         close = bool(branchidx & _rbccloseflag)
         if close:
             branchidx &= _rbcbranchidxmask
         if cachenode == '\0\0\0\0':
             pass
         elif cachenode == reponode:
             try:
                 return self._names[branchidx], close
             except IndexError:
                 # recover from invalid reference to unknown branch
                 self._repo.ui.debug("referenced branch names not found"
                     " - rebuilding revision branch cache from scratch\n")
                 self._clear()
         else:
             # rev/node map has changed, invalidate the cache from here up
             self._repo.ui.debug("history modification detected - truncating "
                 "revision branch cache to revision %s\n" % rev)
             truncate = rbcrevidx + _rbcrecsize
             del self._rbcrevs[truncate:]
             self._rbcrevslen = min(self._rbcrevslen, truncate)
 
         # fall back to slow path and make sure it will be written to disk
         return self._branchinfo(rev)
 
     def _branchinfo(self, rev):
         """Retrieve branch info from changelog and update _rbcrevs"""
         changelog = self._repo.changelog
         b, close = changelog.branchinfo(rev)
         if b in self._namesreverse:
             branchidx = self._namesreverse[b]
         else:
             branchidx = len(self._names)
             self._names.append(b)
             self._namesreverse[b] = branchidx
         reponode = changelog.node(rev)
         if close:
             branchidx |= _rbccloseflag
         self._setcachedata(rev, reponode, branchidx)
         return b, close
 
     def _setcachedata(self, rev, node, branchidx):
         """Writes the node's branch data to the in-memory cache data."""
         rbcrevidx = rev * _rbcrecsize
         rec = array('c')
         rec.fromstring(pack(_rbcrecfmt, node, branchidx))
         if len(self._rbcrevs) < rbcrevidx + _rbcrecsize:
             self._rbcrevs.extend('\0' *
                                  (len(self._repo.changelog) * _rbcrecsize -
                                   len(self._rbcrevs)))
         self._rbcrevs[rbcrevidx:rbcrevidx + _rbcrecsize] = rec
         self._rbcrevslen = min(self._rbcrevslen, rev)
 
         tr = self._repo.currenttransaction()
         if tr:
             tr.addfinalize('write-revbranchcache', self.write)
 
     def write(self, tr=None):
         """Save branch cache if it is dirty."""
         repo = self._repo
-        if True:
+        wlock = None
+        try:
             if self._rbcnamescount < len(self._names):
+                wlock = repo.wlock(wait=False)
                 try:
                     if self._rbcnamescount != 0:
                         f = repo.vfs.open(_rbcnames, 'ab')
                         if f.tell() == self._rbcsnameslen:
                             f.write('\0')
                         else:
                             f.close()
                             repo.ui.debug("%s changed - rewriting it\n"
                                           % _rbcnames)
                             self._rbcnamescount = 0
                             self._rbcrevslen = 0
                     if self._rbcnamescount == 0:
                         # before rewriting names, make sure references are
                         # removed
                         repo.vfs.unlinkpath(_rbcrevs, ignoremissing=True)
                         f = repo.vfs.open(_rbcnames, 'wb')
                     f.write('\0'.join(encoding.fromlocal(b)
                                       for b in self._names[self._rbcnamescount:]
                                       ))
                     self._rbcsnameslen = f.tell()
                     f.close()
                 except (IOError, OSError, error.Abort) as inst:
                     repo.ui.debug("couldn't write revision branch cache names: "
                                   "%s\n" % inst)
                     return
                 self._rbcnamescount = len(self._names)
 
             start = self._rbcrevslen * _rbcrecsize
             if start != len(self._rbcrevs):
+                if wlock is None:
+                    wlock = repo.wlock(wait=False)
                 revs = min(len(repo.changelog),
                            len(self._rbcrevs) // _rbcrecsize)
                 try:
                     f = repo.vfs.open(_rbcrevs, 'ab')
                     if f.tell() != start:
                         repo.ui.debug("truncating %s to %s\n"
                                       % (_rbcrevs, start))
                         f.seek(start)
                         if f.tell() != start:
                             start = 0
                             f.seek(start)
                         f.truncate()
                     end = revs * _rbcrecsize
                     f.write(self._rbcrevs[start:end])
                     f.close()
                 except (IOError, OSError, error.Abort) as inst:
                     repo.ui.debug("couldn't write revision branch cache: %s\n" %
                                   inst)
                     return
                 self._rbcrevslen = revs
+        except error.LockError as inst:
+            repo.ui.debug("couldn't write revision branch cache: %s\n" % inst)
+        finally:
+            if wlock is not None:
+                wlock.release()

tests/test-branches.t

@@ -1,702 +1,714
   $ hg init a
   $ cd a
   $ echo 'root' >root
   $ hg add root
   $ hg commit -d '0 0' -m "Adding root node"
 
   $ echo 'a' >a
   $ hg add a
   $ hg branch a
   marked working directory as branch a
   (branches are permanent and global, did you want a bookmark?)
   $ hg commit -d '1 0' -m "Adding a branch"
 
   $ hg branch q
   marked working directory as branch q
   $ echo 'aa' >a
   $ hg branch -C
   reset working directory to branch a
   $ hg commit -d '2 0' -m "Adding to a branch"
 
   $ hg update -C 0
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo 'b' >b
   $ hg add b
   $ hg branch b
   marked working directory as branch b
   $ hg commit -d '2 0' -m "Adding b branch"
 
   $ echo 'bh1' >bh1
   $ hg add bh1
   $ hg commit -d '3 0' -m "Adding b branch head 1"
 
   $ hg update -C 2
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ echo 'bh2' >bh2
   $ hg add bh2
   $ hg commit -d '4 0' -m "Adding b branch head 2"
 
   $ echo 'c' >c
   $ hg add c
   $ hg branch c
   marked working directory as branch c
   $ hg commit -d '5 0' -m "Adding c branch"
 
 reserved names
 
   $ hg branch tip
   abort: the name 'tip' is reserved
   [255]
   $ hg branch null
   abort: the name 'null' is reserved
   [255]
   $ hg branch .
   abort: the name '.' is reserved
   [255]
 
 invalid characters
 
   $ hg branch 'foo:bar'
   abort: ':' cannot be used in a name
   [255]
 
   $ hg branch 'foo
   > bar'
   abort: '\n' cannot be used in a name
   [255]
 
 trailing or leading spaces should be stripped before testing duplicates
 
   $ hg branch 'b '
   abort: a branch of the same name already exists
   (use 'hg update' to switch to it)
   [255]
 
   $ hg branch ' b'
   abort: a branch of the same name already exists
   (use 'hg update' to switch to it)
   [255]
 
 verify update will accept invalid legacy branch names
 
   $ hg init test-invalid-branch-name
   $ cd test-invalid-branch-name
   $ hg pull -u "$TESTDIR"/bundles/test-invalid-branch-name.hg
   pulling from *test-invalid-branch-name.hg (glob)
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 3 changesets with 3 changes to 2 files
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ hg update '"colon:test"'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ..
 
   $ echo 'd' >d
   $ hg add d
   $ hg branch 'a branch name much longer than the default justification used by branches'
   marked working directory as branch a branch name much longer than the default justification used by branches
   $ hg commit -d '6 0' -m "Adding d branch"
 
   $ hg branches
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   b                              4:aee39cd168d0
   c                              6:589736a22561 (inactive)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
 
 -------
 
   $ hg branches -a
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   b                              4:aee39cd168d0
 
 --- Branch a
 
   $ hg log -b a
   changeset:   5:d8cbc61dbaa6
   branch:      a
   parent:      2:881fe2b92ad0
   user:        test
   date:        Thu Jan 01 00:00:04 1970 +0000
   summary:     Adding b branch head 2
   
   changeset:   2:881fe2b92ad0
   branch:      a
   user:        test
   date:        Thu Jan 01 00:00:02 1970 +0000
   summary:     Adding to a branch
   
   changeset:   1:dd6b440dd85a
   branch:      a
   user:        test
   date:        Thu Jan 01 00:00:01 1970 +0000
   summary:     Adding a branch
   
 
 ---- Branch b
 
   $ hg log -b b
   changeset:   4:aee39cd168d0
   branch:      b
   user:        test
   date:        Thu Jan 01 00:00:03 1970 +0000
   summary:     Adding b branch head 1
   
   changeset:   3:ac22033332d1
   branch:      b
   parent:      0:19709c5a4e75
   user:        test
   date:        Thu Jan 01 00:00:02 1970 +0000
   summary:     Adding b branch
   
 
 ---- going to test branch closing
 
   $ hg branches
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   b                              4:aee39cd168d0
   c                              6:589736a22561 (inactive)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
   $ hg up -C b
   2 files updated, 0 files merged, 4 files removed, 0 files unresolved
   $ echo 'xxx1' >> b
   $ hg commit -d '7 0' -m 'adding cset to branch b'
   $ hg up -C aee39cd168d0
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo 'xxx2' >> b
   $ hg commit -d '8 0' -m 'adding head to branch b'
   created new head
   $ echo 'xxx3' >> b
   $ hg commit -d '9 0' -m 'adding another cset to branch b'
   $ hg branches
   b                             10:bfbe841b666e
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   c                              6:589736a22561 (inactive)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
   $ hg heads --closed
   changeset:   10:bfbe841b666e
   branch:      b
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     adding another cset to branch b
   
   changeset:   8:eebb944467c9
   branch:      b
   parent:      4:aee39cd168d0
   user:        test
   date:        Thu Jan 01 00:00:07 1970 +0000
   summary:     adding cset to branch b
   
   changeset:   7:10ff5895aa57
   branch:      a branch name much longer than the default justification used by branches
   user:        test
   date:        Thu Jan 01 00:00:06 1970 +0000
   summary:     Adding d branch
   
   changeset:   6:589736a22561
   branch:      c
   user:        test
   date:        Thu Jan 01 00:00:05 1970 +0000
   summary:     Adding c branch
   
   changeset:   5:d8cbc61dbaa6
   branch:      a
   parent:      2:881fe2b92ad0
   user:        test
   date:        Thu Jan 01 00:00:04 1970 +0000
   summary:     Adding b branch head 2
   
   changeset:   0:19709c5a4e75
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Adding root node
   
   $ hg heads
   changeset:   10:bfbe841b666e
   branch:      b
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     adding another cset to branch b
   
   changeset:   8:eebb944467c9
   branch:      b
   parent:      4:aee39cd168d0
   user:        test
   date:        Thu Jan 01 00:00:07 1970 +0000
   summary:     adding cset to branch b
   
   changeset:   7:10ff5895aa57
   branch:      a branch name much longer than the default justification used by branches
   user:        test
   date:        Thu Jan 01 00:00:06 1970 +0000
   summary:     Adding d branch
   
   changeset:   6:589736a22561
   branch:      c
   user:        test
   date:        Thu Jan 01 00:00:05 1970 +0000
   summary:     Adding c branch
   
   changeset:   5:d8cbc61dbaa6
   branch:      a
   parent:      2:881fe2b92ad0
   user:        test
   date:        Thu Jan 01 00:00:04 1970 +0000
   summary:     Adding b branch head 2
   
   changeset:   0:19709c5a4e75
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Adding root node
   
   $ hg commit -d '9 0' --close-branch -m 'prune bad branch'
   $ hg branches -a
   b                              8:eebb944467c9
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   $ hg up -C b
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg commit -d '9 0' --close-branch -m 'close this part branch too'
   $ hg commit -d '9 0' --close-branch -m 're-closing this branch'
   abort: can only close branch heads
   [255]
 
   $ hg log -r tip --debug
   changeset:   12:e3d49c0575d8fc2cb1cd6859c747c14f5f6d499f
   branch:      b
   tag:         tip
   phase:       draft
   parent:      8:eebb944467c9fb9651ed232aeaf31b3c0a7fc6c1
   parent:      -1:0000000000000000000000000000000000000000
   manifest:    8:6f9ed32d2b310e391a4f107d5f0f071df785bfee
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   extra:       branch=b
   extra:       close=1
   description:
   close this part branch too
   
   
 --- b branch should be inactive
 
   $ hg branches
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   c                              6:589736a22561 (inactive)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
   $ hg branches -c
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   b                             12:e3d49c0575d8 (closed)
   c                              6:589736a22561 (inactive)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
   $ hg branches -a
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   $ hg branches -q
   a branch name much longer than the default justification used by branches
   c
   a
   default
   $ hg heads b
   no open branch heads found on branches b
   [1]
   $ hg heads --closed b
   changeset:   12:e3d49c0575d8
   branch:      b
   tag:         tip
   parent:      8:eebb944467c9
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     close this part branch too
   
   changeset:   11:d3f163457ebf
   branch:      b
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     prune bad branch
   
   $ echo 'xxx4' >> b
   $ hg commit -d '9 0' -m 'reopen branch with a change'
   reopening closed branch head 12
 
 --- branch b is back in action
 
   $ hg branches -a
   b                             13:e23b5505d1ad
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
 
 ---- test heads listings
 
   $ hg heads
   changeset:   13:e23b5505d1ad
   branch:      b
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     reopen branch with a change
   
   changeset:   7:10ff5895aa57
   branch:      a branch name much longer than the default justification used by branches
   user:        test
   date:        Thu Jan 01 00:00:06 1970 +0000
   summary:     Adding d branch
   
   changeset:   6:589736a22561
   branch:      c
   user:        test
   date:        Thu Jan 01 00:00:05 1970 +0000
   summary:     Adding c branch
   
   changeset:   5:d8cbc61dbaa6
   branch:      a
   parent:      2:881fe2b92ad0
   user:        test
   date:        Thu Jan 01 00:00:04 1970 +0000
   summary:     Adding b branch head 2
   
   changeset:   0:19709c5a4e75
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Adding root node
   
 
 branch default
 
   $ hg heads default
   changeset:   0:19709c5a4e75
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Adding root node
   
 
 branch a
 
   $ hg heads a
   changeset:   5:d8cbc61dbaa6
   branch:      a
   parent:      2:881fe2b92ad0
   user:        test
   date:        Thu Jan 01 00:00:04 1970 +0000
   summary:     Adding b branch head 2
   
   $ hg heads --active a
   no open branch heads found on branches a
   [1]
 
 branch b
 
   $ hg heads b
   changeset:   13:e23b5505d1ad
   branch:      b
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     reopen branch with a change
   
   $ hg heads --closed b
   changeset:   13:e23b5505d1ad
   branch:      b
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     reopen branch with a change
   
   changeset:   11:d3f163457ebf
   branch:      b
   user:        test
   date:        Thu Jan 01 00:00:09 1970 +0000
   summary:     prune bad branch
   
 default branch colors:
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > color =
   > [color]
   > mode = ansi
   > EOF
 
   $ hg up -C c
   3 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ hg commit -d '9 0' --close-branch -m 'reclosing this branch'
   $ hg up -C b
   2 files updated, 0 files merged, 3 files removed, 0 files unresolved
   $ hg branches --color=always
   \x1b[0;32mb\x1b[0m\x1b[0;33m                             13:e23b5505d1ad\x1b[0m (esc)
   \x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;33m 7:10ff5895aa57\x1b[0m (esc)
   \x1b[0;0ma\x1b[0m\x1b[0;33m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
   \x1b[0;0mdefault\x1b[0m\x1b[0;33m                        0:19709c5a4e75\x1b[0m (inactive) (esc)
 
 default closed branch color:
 
   $ hg branches --color=always --closed
   \x1b[0;32mb\x1b[0m\x1b[0;33m                             13:e23b5505d1ad\x1b[0m (esc)
   \x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;33m 7:10ff5895aa57\x1b[0m (esc)
   \x1b[0;30;1mc\x1b[0m\x1b[0;33m                             14:f894c25619d3\x1b[0m (closed) (esc)
   \x1b[0;0ma\x1b[0m\x1b[0;33m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
   \x1b[0;0mdefault\x1b[0m\x1b[0;33m                        0:19709c5a4e75\x1b[0m (inactive) (esc)
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > color =
   > [color]
   > branches.active = green
   > branches.closed = blue
   > branches.current = red
   > branches.inactive = magenta
   > log.changeset = cyan
   > EOF
 
 custom branch colors:
 
   $ hg branches --color=always
   \x1b[0;31mb\x1b[0m\x1b[0;36m                             13:e23b5505d1ad\x1b[0m (esc)
   \x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;36m 7:10ff5895aa57\x1b[0m (esc)
   \x1b[0;35ma\x1b[0m\x1b[0;36m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
   \x1b[0;35mdefault\x1b[0m\x1b[0;36m                        0:19709c5a4e75\x1b[0m (inactive) (esc)
 
 custom closed branch color:
 
   $ hg branches --color=always --closed
   \x1b[0;31mb\x1b[0m\x1b[0;36m                             13:e23b5505d1ad\x1b[0m (esc)
   \x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;36m 7:10ff5895aa57\x1b[0m (esc)
   \x1b[0;34mc\x1b[0m\x1b[0;36m                             14:f894c25619d3\x1b[0m (closed) (esc)
   \x1b[0;35ma\x1b[0m\x1b[0;36m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
   \x1b[0;35mdefault\x1b[0m\x1b[0;36m                        0:19709c5a4e75\x1b[0m (inactive) (esc)
 
 template output:
 
   $ hg branches -Tjson --closed
   [
    {
     "active": true,
     "branch": "b",
     "closed": false,
     "current": true,
     "node": "e23b5505d1ad24aab6f84fd8c7cb8cd8e5e93be0",
     "rev": 13
    },
    {
     "active": true,
     "branch": "a branch name much longer than the default justification used by branches",
     "closed": false,
     "current": false,
     "node": "10ff5895aa5793bd378da574af8cec8ea408d831",
     "rev": 7
    },
    {
     "active": false,
     "branch": "c",
     "closed": true,
     "current": false,
     "node": "f894c25619d3f1484639d81be950e0a07bc6f1f6",
     "rev": 14
    },
    {
     "active": false,
     "branch": "a",
     "closed": false,
     "current": false,
     "node": "d8cbc61dbaa6dc817175d1e301eecb863f280832",
     "rev": 5
    },
    {
     "active": false,
     "branch": "default",
     "closed": false,
     "current": false,
     "node": "19709c5a4e75bf938f8e349aff97438539bb729e",
     "rev": 0
    }
   ]
 
 
 Tests of revision branch name caching
 
 We rev branch cache is updated automatically. In these tests we use a trick to
 trigger rebuilds. We remove the branch head cache and run 'hg head' to cause a
 rebuild that also will populate the rev branch cache.
 
 revision branch cache is created when building the branch head cache
   $ rm -rf .hg/cache; hg head a -T '{rev}\n'
   5
   $ f --hexdump --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=87
   0000: 64 65 66 61 75 6c 74 00 61 00 62 00 63 00 61 20 |default.a.b.c.a |
   0010: 62 72 61 6e 63 68 20 6e 61 6d 65 20 6d 75 63 68 |branch name much|
   0020: 20 6c 6f 6e 67 65 72 20 74 68 61 6e 20 74 68 65 | longer than the|
   0030: 20 64 65 66 61 75 6c 74 20 6a 75 73 74 69 66 69 | default justifi|
   0040: 63 61 74 69 6f 6e 20 75 73 65 64 20 62 79 20 62 |cation used by b|
   0050: 72 61 6e 63 68 65 73                            |ranches|
   .hg/cache/rbc-revs-v1: size=120
   0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
   0010: 88 1f e2 b9 00 00 00 01 ac 22 03 33 00 00 00 02 |.........".3....|
   0020: ae e3 9c d1 00 00 00 02 d8 cb c6 1d 00 00 00 01 |................|
   0030: 58 97 36 a2 00 00 00 03 10 ff 58 95 00 00 00 04 |X.6.......X.....|
   0040: ee bb 94 44 00 00 00 02 5f 40 61 bb 00 00 00 02 |...D...._@a.....|
   0050: bf be 84 1b 00 00 00 02 d3 f1 63 45 80 00 00 02 |..........cE....|
   0060: e3 d4 9c 05 80 00 00 02 e2 3b 55 05 00 00 00 02 |.........;U.....|
   0070: f8 94 c2 56 80 00 00 03                         |...V....|
 
 no errors when revbranchcache is not writable
 
   $ echo >> .hg/cache/rbc-revs-v1
   $ mv .hg/cache/rbc-revs-v1 .hg/cache/rbc-revs-v1_
   $ mkdir .hg/cache/rbc-revs-v1
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n'
   5
   $ rmdir .hg/cache/rbc-revs-v1
   $ mv .hg/cache/rbc-revs-v1_ .hg/cache/rbc-revs-v1
 
+no errors when wlock cannot be acquired
+
+#if unix-permissions
+  $ mv .hg/cache/rbc-revs-v1 .hg/cache/rbc-revs-v1_
+  $ rm -f .hg/cache/branch*
+  $ chmod 555 .hg
+  $ hg head a -T '{rev}\n'
+  5
+  $ chmod 755 .hg
+  $ mv .hg/cache/rbc-revs-v1_ .hg/cache/rbc-revs-v1
+#endif
+
 recovery from invalid cache revs file with trailing data
   $ echo >> .hg/cache/rbc-revs-v1
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   truncating cache/rbc-revs-v1 to 120
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=120
 recovery from invalid cache file with partial last record
   $ mv .hg/cache/rbc-revs-v1 .
   $ f -qDB 119 rbc-revs-v1 > .hg/cache/rbc-revs-v1
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=119
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   truncating cache/rbc-revs-v1 to 112
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=120
 recovery from invalid cache file with missing record - no truncation
   $ mv .hg/cache/rbc-revs-v1 .
   $ f -qDB 112 rbc-revs-v1 > .hg/cache/rbc-revs-v1
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=120
 recovery from invalid cache file with some bad records
   $ mv .hg/cache/rbc-revs-v1 .
   $ f -qDB 8 rbc-revs-v1 > .hg/cache/rbc-revs-v1
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=8
   $ f -qDB 112 rbc-revs-v1 >> .hg/cache/rbc-revs-v1
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=120
   $ hg log -r 'branch(.)' -T '{rev} ' --debug
   history modification detected - truncating revision branch cache to revision 13
   history modification detected - truncating revision branch cache to revision 1
   3 4 8 9 10 11 12 13 truncating cache/rbc-revs-v1 to 8
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   truncating cache/rbc-revs-v1 to 104
   $ f --size --hexdump --bytes=16 .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=120
   0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
 cache is updated when committing
   $ hg branch i-will-regret-this
   marked working directory as branch i-will-regret-this
   $ hg ci -m regrets
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=106
   .hg/cache/rbc-revs-v1: size=128
 update after rollback - the cache will be correct but rbc-names will will still
 contain the branch name even though it no longer is used
   $ hg up -qr '.^'
   $ hg rollback -qf
   $ f --size --hexdump .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=106
   0000: 64 65 66 61 75 6c 74 00 61 00 62 00 63 00 61 20 |default.a.b.c.a |
   0010: 62 72 61 6e 63 68 20 6e 61 6d 65 20 6d 75 63 68 |branch name much|
   0020: 20 6c 6f 6e 67 65 72 20 74 68 61 6e 20 74 68 65 | longer than the|
   0030: 20 64 65 66 61 75 6c 74 20 6a 75 73 74 69 66 69 | default justifi|
   0040: 63 61 74 69 6f 6e 20 75 73 65 64 20 62 79 20 62 |cation used by b|
   0050: 72 61 6e 63 68 65 73 00 69 2d 77 69 6c 6c 2d 72 |ranches.i-will-r|
   0060: 65 67 72 65 74 2d 74 68 69 73                   |egret-this|
   .hg/cache/rbc-revs-v1: size=120
   0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
   0010: 88 1f e2 b9 00 00 00 01 ac 22 03 33 00 00 00 02 |.........".3....|
   0020: ae e3 9c d1 00 00 00 02 d8 cb c6 1d 00 00 00 01 |................|
   0030: 58 97 36 a2 00 00 00 03 10 ff 58 95 00 00 00 04 |X.6.......X.....|
   0040: ee bb 94 44 00 00 00 02 5f 40 61 bb 00 00 00 02 |...D...._@a.....|
   0050: bf be 84 1b 00 00 00 02 d3 f1 63 45 80 00 00 02 |..........cE....|
   0060: e3 d4 9c 05 80 00 00 02 e2 3b 55 05 00 00 00 02 |.........;U.....|
   0070: f8 94 c2 56 80 00 00 03                         |...V....|
 cache is updated/truncated when stripping - it is thus very hard to get in a
 situation where the cache is out of sync and the hash check detects it
   $ hg --config extensions.strip= strip -r tip --nob
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v1: size=112
 
 cache is rebuilt when corruption is detected
   $ echo > .hg/cache/rbc-names-v1
   $ hg log -r '5:&branch(.)' -T '{rev} ' --debug
   referenced branch names not found - rebuilding revision branch cache from scratch
   8 9 10 11 12 13 truncating cache/rbc-revs-v1 to 40
   $ f --size --hexdump .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=79
   0000: 62 00 61 00 63 00 61 20 62 72 61 6e 63 68 20 6e |b.a.c.a branch n|
   0010: 61 6d 65 20 6d 75 63 68 20 6c 6f 6e 67 65 72 20 |ame much longer |
   0020: 74 68 61 6e 20 74 68 65 20 64 65 66 61 75 6c 74 |than the default|
   0030: 20 6a 75 73 74 69 66 69 63 61 74 69 6f 6e 20 75 | justification u|
   0040: 73 65 64 20 62 79 20 62 72 61 6e 63 68 65 73    |sed by branches|
   .hg/cache/rbc-revs-v1: size=112
   0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0020: 00 00 00 00 00 00 00 00 d8 cb c6 1d 00 00 00 01 |................|
   0030: 58 97 36 a2 00 00 00 02 10 ff 58 95 00 00 00 03 |X.6.......X.....|
   0040: ee bb 94 44 00 00 00 00 5f 40 61 bb 00 00 00 00 |...D...._@a.....|
   0050: bf be 84 1b 00 00 00 00 d3 f1 63 45 80 00 00 00 |..........cE....|
   0060: e3 d4 9c 05 80 00 00 00 e2 3b 55 05 00 00 00 00 |.........;U.....|
 
 Test that cache files are created and grows correctly:
 
   $ rm .hg/cache/rbc*
   $ hg log -r "5 & branch(5)" -T "{rev}\n"
   5
   $ f --size --hexdump .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=1
   0000: 61                                              |a|
   .hg/cache/rbc-revs-v1: size=112
   0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0020: 00 00 00 00 00 00 00 00 d8 cb c6 1d 00 00 00 00 |................|
   0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
   0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
 
   $ cd ..
 
 Test for multiple incorrect branch cache entries:
 
   $ hg init b
   $ cd b
   $ touch f
   $ hg ci -Aqmf
   $ echo >> f
   $ hg ci -Amf
   $ hg branch -q branch
   $ hg ci -Amf
 
   $ f --size --hexdump .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=14
   0000: 64 65 66 61 75 6c 74 00 62 72 61 6e 63 68       |default.branch|
   .hg/cache/rbc-revs-v1: size=24
   0000: 66 e5 f5 aa 00 00 00 00 fa 4c 04 e5 00 00 00 00 |f........L......|
   0010: 56 46 78 69 00 00 00 01                         |VFxi....|
   $ : > .hg/cache/rbc-revs-v1
 
 No superfluous rebuilding of cache:
   $ hg log -r "branch(null)&branch(branch)" --debug
   $ f --size --hexdump .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=14
   0000: 64 65 66 61 75 6c 74 00 62 72 61 6e 63 68       |default.branch|
   .hg/cache/rbc-revs-v1: size=24
   0000: 66 e5 f5 aa 00 00 00 00 fa 4c 04 e5 00 00 00 00 |f........L......|
   0010: 56 46 78 69 00 00 00 01                         |VFxi....|
 
   $ cd ..