rev-branch-cache: properly ignores unaligned trailing data

Previously, trailing data could lead to crash and would be written back to disk,
disaligning all new data…

This is no longer the cases.

This was detected while playing with branchmap-v3 that access the
rev-branch-cache much more aggressively.

mercurial/branching/rev_cache.py

@@ -1,434 +1,442
 # rev_cache.py - caching branch information per revision
 #
 # 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 annotations
 
 import os
 import struct
 
 from ..node import (
     nullrev,
 )
 
 from .. import (
     encoding,
     error,
     util,
 )
 
 from ..utils import (
     stringutil,
 )
 
 calcsize = struct.calcsize
 pack_into = struct.pack_into
 unpack_from = struct.unpack_from
 
 
 # Revision branch info cache
 
 # The "V2" version use the same format as the "V1" but garantee it won't be
 # truncated, preventing SIGBUS when it is mmap-ed
 _rbcversion = b'-v2'
 _rbcnames = b'rbc-names' + _rbcversion
 _rbcrevs = b'rbc-revs' + _rbcversion
 _rbc_legacy_version = b'-v1'
 _rbc_legacy_names = b'rbc-names' + _rbc_legacy_version
 _rbc_legacy_revs = b'rbc-revs' + _rbc_legacy_version
 # [4 byte hash prefix][4 byte branch name number with sign bit indicating open]
 _rbcrecfmt = b'>4sI'
 _rbcrecsize = calcsize(_rbcrecfmt)
 _rbcmininc = 64 * _rbcrecsize
 _rbcnodelen = 4
 _rbcbranchidxmask = 0x7FFFFFFF
 _rbccloseflag = 0x80000000
 
 
 # with atomic replacement.
 REWRITE_RATIO = 0.2
 
 
 class rbcrevs:
     """a byte string consisting of an immutable prefix followed by a mutable suffix"""
 
     def __init__(self, revs):
         self._prefix = revs
         self._rest = bytearray()
 
+    @property
+    def len_prefix(self):
+        size = len(self._prefix)
+        return size - (size % _rbcrecsize)
+
     def __len__(self):
-        return len(self._prefix) + len(self._rest)
+        return self.len_prefix + len(self._rest)
 
     def unpack_record(self, rbcrevidx):
-        if rbcrevidx < len(self._prefix):
+        if rbcrevidx < self.len_prefix:
             return unpack_from(_rbcrecfmt, util.buffer(self._prefix), rbcrevidx)
         else:
             return unpack_from(
                 _rbcrecfmt,
                 util.buffer(self._rest),
-                rbcrevidx - len(self._prefix),
+                rbcrevidx - self.len_prefix,
             )
 
     def make_mutable(self):
-        if len(self._prefix) > 0:
+        if self.len_prefix > 0:
             entirety = bytearray()
-            entirety[:] = self._prefix
+            entirety[:] = self._prefix[: self.len_prefix]
             entirety.extend(self._rest)
             self._rest = entirety
             self._prefix = bytearray()
 
     def truncate(self, pos):
         self.make_mutable()
         del self._rest[pos:]
 
     def pack_into(self, rbcrevidx, node, branchidx):
-        if rbcrevidx < len(self._prefix):
+        if rbcrevidx < self.len_prefix:
             self.make_mutable()
         buf = self._rest
-        start_offset = rbcrevidx - len(self._prefix)
+        start_offset = rbcrevidx - self.len_prefix
         end_offset = start_offset + _rbcrecsize
 
         if len(self._rest) < end_offset:
             # bytearray doesn't allocate extra space at least in Python 3.7.
             # When multiple changesets are added in a row, precise resize would
             # result in quadratic complexity. Overallocate to compensate by
             # using the classic doubling technique for dynamic arrays instead.
             # If there was a gap in the map before, less space will be reserved.
             self._rest.extend(b'\0' * end_offset)
         return pack_into(
             _rbcrecfmt,
             buf,
             start_offset,
             node,
             branchidx,
         )
 
     def extend(self, extension):
         return self._rest.extend(extension)
 
     def slice(self, begin, end):
-        if begin < len(self._prefix):
+        if begin < self.len_prefix:
             acc = bytearray()
-            acc[:] = self._prefix[begin:end]
+            acc[:] = self._prefix[begin : min(end, self.len_prefix)]
             acc.extend(
-                self._rest[begin - len(self._prefix) : end - len(self._prefix)]
+                self._rest[begin - self.len_prefix : end - self.len_prefix]
             )
             return acc
-        return self._rest[begin - len(self._prefix) : end - len(self._prefix)]
+        return self._rest[begin - self.len_prefix : end - self.len_prefix]
 
 
 class revbranchcache:
     """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 = rbcrevs(bytearray())
         self._rbcsnameslen = 0  # length of names read at _rbcsnameslen
         self._force_overwrite = False
         v1_fallback = False
         try:
             try:
                 bndata = repo.cachevfs.read(_rbcnames)
             except (IOError, OSError):
                 # If we don't have "v2" data, we might have "v1" data worth
                 # using.
                 #
                 # consider stop doing this many version after hg-6.9 release
                 bndata = repo.cachevfs.read(_rbc_legacy_names)
                 v1_fallback = True
                 self._force_overwrite = True
             self._rbcsnameslen = len(bndata)  # for verification before writing
             if bndata:
                 self._names = [
                     encoding.tolocal(bn) for bn in bndata.split(b'\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:
                 usemmap = repo.ui.configbool(b'storage', b'revbranchcache.mmap')
                 if not v1_fallback:
                     with repo.cachevfs(_rbcrevs) as fp:
                         if usemmap and repo.cachevfs.is_mmap_safe(_rbcrevs):
                             data = util.buffer(util.mmapread(fp))
                         else:
                             data = fp.read()
                 else:
                     # If we don't have "v2" data, we might have "v1" data worth
                     # using.
                     #
                     # Consider stop doing this many version after hg-6.9
                     # release.
                     with repo.cachevfs(_rbc_legacy_revs) as fp:
                         data = fp.read()
                 self._rbcrevs = rbcrevs(data)
             except (IOError, OSError) as inst:
                 repo.ui.debug(
                     b"couldn't read revision branch cache: %s\n"
                     % stringutil.forcebytestr(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
 
     def _clear(self):
         self._rbcsnameslen = 0
         del self._names[:]
         self._rbcnamescount = 0
         self._rbcrevslen = len(self._repo.changelog)
         self._rbcrevs = rbcrevs(bytearray(self._rbcrevslen * _rbcrecsize))
         util.clearcachedproperty(self, b'_namesreverse')
         self._force_overwrite = True
 
     def invalidate(self, rev=0):
         self._rbcrevslen = rev
         self._rbcrevs.truncate(rev)
         self._force_overwrite = True
 
     @util.propertycache
     def _namesreverse(self):
         return {b: r for r, b in enumerate(self._names)}
 
     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 = self._rbcrevs.unpack_record(rbcrevidx)
         close = bool(branchidx & _rbccloseflag)
         if close:
             branchidx &= _rbcbranchidxmask
         if cachenode == b'\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(
                     b"referenced branch names not found"
                     b" - 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(
                 b"history modification detected - truncating "
                 b"revision branch cache to revision %d\n" % rev
             )
             truncate = rbcrevidx + _rbcrecsize
             self._rbcrevs.truncate(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 setdata(self, rev, changelogrevision):
         """add new data information to the cache"""
         branch, close = changelogrevision.branchinfo
 
         if branch in self._namesreverse:
             branchidx = self._namesreverse[branch]
         else:
             branchidx = len(self._names)
             self._names.append(branch)
             self._namesreverse[branch] = branchidx
         if close:
             branchidx |= _rbccloseflag
         self._setcachedata(rev, self._repo.changelog.node(rev), branchidx)
         # If no cache data were readable (non exists, bad permission, etc)
         # the cache was bypassing itself by setting:
         #
         #   self.branchinfo = self._branchinfo
         #
         # Since we now have data in the cache, we need to drop this bypassing.
         if 'branchinfo' in vars(self):
             del self.branchinfo
 
     def _setcachedata(self, rev, node, branchidx):
         """Writes the node's branch data to the in-memory cache data."""
         if rev == nullrev:
             return
         rbcrevidx = rev * _rbcrecsize
         self._rbcrevs.pack_into(rbcrevidx, node, branchidx)
         self._rbcrevslen = min(self._rbcrevslen, rev)
 
         tr = self._repo.currenttransaction()
         if tr:
             tr.addfinalize(b'write-revbranchcache', self.write)
 
     def write(self, tr=None):
         """Save branch cache if it is dirty."""
         repo = self._repo
         wlock = None
         step = b''
         try:
             # write the new names
             if self._force_overwrite or self._rbcnamescount < len(self._names):
                 wlock = repo.wlock(wait=False)
                 step = b' names'
                 self._writenames(repo)
 
             # write the new revs
             start = self._rbcrevslen * _rbcrecsize
             if self._force_overwrite or start != len(self._rbcrevs):
                 step = b''
                 if wlock is None:
                     wlock = repo.wlock(wait=False)
                 self._writerevs(repo, start)
 
         except (IOError, OSError, error.Abort, error.LockError) as inst:
             repo.ui.debug(
                 b"couldn't write revision branch cache%s: %s\n"
                 % (step, stringutil.forcebytestr(inst))
             )
         finally:
             if wlock is not None:
                 wlock.release()
 
     def _writenames(self, repo):
         """write the new branch names to revbranchcache"""
         f = None
         if self._force_overwrite:
             self._rbcsnameslen = 0
             self._rbcnamescount = 0
         try:
             if self._force_overwrite or self._rbcnamescount != 0:
                 f = repo.cachevfs.open(_rbcnames, b'ab')
                 current_size = f.tell()
                 if current_size == self._rbcsnameslen:
                     f.write(b'\0')
                 else:
                     f.close()
                     if self._force_overwrite:
                         dbg = b"resetting content of %s\n"
                     elif current_size > 0:
                         dbg = b"%s changed - rewriting it\n"
                     else:
                         dbg = b"%s is missing - rewriting it\n"
                     repo.ui.debug(dbg % _rbcnames)
                     self._rbcnamescount = 0
                     self._rbcrevslen = 0
             if self._rbcnamescount == 0:
                 # before rewriting names, make sure references are removed
                 repo.cachevfs.unlinkpath(_rbcrevs, ignoremissing=True)
                 f = repo.cachevfs.open(_rbcnames, b'wb')
             names = self._names[self._rbcnamescount :]
             from_local = encoding.fromlocal
             data = b'\0'.join(from_local(b) for b in names)
             f.write(data)
             self._rbcsnameslen = f.tell()
         finally:
             if f is not None:
                 f.close()
         self._rbcnamescount = len(self._names)
 
     def _writerevs(self, repo, start):
         """write the new revs to revbranchcache"""
         revs = min(len(repo.changelog), len(self._rbcrevs) // _rbcrecsize)
 
         end = revs * _rbcrecsize
         if self._force_overwrite:
             start = 0
 
+        # align start on entry boundary
+        start = _rbcrecsize * (start // _rbcrecsize)
+
         with repo.cachevfs.open(_rbcrevs, b'a+b') as f:
             pass  # this make sure the file exist…
         with repo.cachevfs.open(_rbcrevs, b'r+b') as f:
             f.seek(0, os.SEEK_END)
             current_size = f.tell()
             if current_size < start:
                 start = 0
             if current_size != start:
                 threshold = current_size * REWRITE_RATIO
                 overwritten = min(end, current_size) - start
                 if (max(end, current_size) - start) >= threshold:
                     start = 0
                     dbg = b"resetting content of cache/%s\n" % _rbcrevs
                     repo.ui.debug(dbg)
                 elif overwritten > 0:
                     # end affected, let us overwrite the bad value
                     dbg = b"overwriting %d bytes from %d in cache/%s"
                     dbg %= (current_size - start, start, _rbcrevs)
                     if end < current_size:
                         extra = b" leaving (%d trailing bytes)"
                         extra %= current_size - end
                         dbg += extra
                     dbg += b'\n'
                     repo.ui.debug(dbg)
                 else:
                     # extra untouched data at the end, lets warn about them
                     assert start == end  # since don't write anything
                     dbg = b"cache/%s contains %d unknown trailing bytes\n"
                     dbg %= (_rbcrevs, current_size - start)
                     repo.ui.debug(dbg)
 
             if start > 0:
                 f.seek(start)
                 f.write(self._rbcrevs.slice(start, end))
             else:
                 f.close()
                 with repo.cachevfs.open(
                     _rbcrevs,
                     b'wb',
                     atomictemp=True,
                 ) as rev_file:
                     rev_file.write(self._rbcrevs.slice(start, end))
         self._rbcrevslen = revs
         self._force_overwrite = False

tests/test-branches.t

@@ -1,1466 +1,1481
 #testcases mmap nommap
 #testcases v2 v3
 
 #if mmap
   $ cat <<EOF >> $HGRCPATH
   > [storage]
   > revbranchcache.mmap=true
   > EOF
 #endif
 
 #if v3
   $ cat <<EOF >> $HGRCPATH
   > [experimental]
   > branch-cache-v3=yes
   > EOF
 #else
   $ cat <<EOF >> $HGRCPATH
   > [experimental]
   > branch-cache-v3=no
   > EOF
 #endif
 
   $ hg init a
   $ cd a
 
 Verify checking branch of nullrev before the cache is created doesnt crash
   $ hg log -r 'branch(.)' -T '{branch}\n'
 
 Basic test
   $ 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
   [10]
   $ hg branch null
   abort: the name 'null' is reserved
   [10]
   $ hg branch .
   abort: the name '.' is reserved
   [10]
 
 invalid characters
 
   $ hg branch 'foo:bar'
   abort: ':' cannot be used in a name
   [10]
 
   $ hg branch 'foo
   > bar'
   abort: '\n' cannot be used in a name
   [10]
 
 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)
   [10]
 
   $ hg branch ' b'
   abort: a branch of the same name already exists
   (use 'hg update' to switch to it)
   [10]
 
 underscores in numeric branch names (issue6737)
 
   $ hg branch 2700_210
   marked working directory as branch 2700_210
 
 verify update will accept invalid legacy branch names
 
   $ hg init test-invalid-branch-name
   $ cd test-invalid-branch-name
   $ hg unbundle -u "$TESTDIR"/bundles/test-invalid-branch-name.hg
   adding changesets
   adding manifests
   adding file changes
   added 3 changesets with 3 changes to 2 files
   new changesets f0e4c7f04036:33c2ceb9310b (3 drafts)
   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 listing by rev
   $ hg branches -r0
   default                        0:19709c5a4e75 (inactive)
   $ hg branches -qr0
   default
 --- now more than one rev
   $ hg branches -r2:5
   b                              4:aee39cd168d0
   a                              5:d8cbc61dbaa6 (inactive)
   $ hg branches -qr2:5
   b
   a
 ---- 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: current revision is already a branch closing head
   [10]
 
   $ echo foo > b
   $ hg commit -d '9 0' --close-branch -m 're-closing this branch'
 
   $ echo bar > b
   $ hg commit -d '9 0' --close-branch -m 're-closing this branch' bh1
   abort: current revision is already a branch closing head
   [10]
   $ hg commit -d '9 0' --close-branch -m 're-closing this branch' b
 
   $ echo baz > b
   $ hg commit -d '9 0' --close-branch -m 'empty re-closing this branch' -X b
   abort: current revision is already a branch closing head
   [10]
   $ hg revert b
 
   $ hg debugstrip --rev 13: --no-backup
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg revert --all --no-backup
 
   $ 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
   
 
 reclose branch
 
   $ 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 branches
   b                             13:e23b5505d1ad
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
   $ hg branches --closed
   b                             13:e23b5505d1ad
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   c                             14:f894c25619d3 (closed)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
 
 multihead branch
 
   $ hg up -C default
   0 files updated, 0 files merged, 3 files removed, 0 files unresolved
   $ hg branch m
   marked working directory as branch m
   $ touch m
   $ hg add m
   $ hg commit -d '10 0' -m 'multihead base'
   $ echo "m1" >m
   $ hg commit -d '10 0' -m 'head 1'
   $ hg up -C '.^'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo "m2" >m
   $ hg commit -d '10 0' -m 'head 2'
   created new head
   $ hg log -b m
   changeset:   17:df343b0df04f
   branch:      m
   tag:         tip
   parent:      15:f3447637f53e
   user:        test
   date:        Thu Jan 01 00:00:10 1970 +0000
   summary:     head 2
   
   changeset:   16:a58ca5d3bdf3
   branch:      m
   user:        test
   date:        Thu Jan 01 00:00:10 1970 +0000
   summary:     head 1
   
   changeset:   15:f3447637f53e
   branch:      m
   parent:      0:19709c5a4e75
   user:        test
   date:        Thu Jan 01 00:00:10 1970 +0000
   summary:     multihead base
   
   $ hg heads --topo m
   changeset:   17:df343b0df04f
   branch:      m
   tag:         tip
   parent:      15:f3447637f53e
   user:        test
   date:        Thu Jan 01 00:00:10 1970 +0000
   summary:     head 2
   
   changeset:   16:a58ca5d3bdf3
   branch:      m
   user:        test
   date:        Thu Jan 01 00:00:10 1970 +0000
   summary:     head 1
   
   $ hg branches
   m                             17:df343b0df04f
   b                             13:e23b5505d1ad
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
 
 partially merge multihead branch
 
   $ hg up -C default
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg branch md
   marked working directory as branch md
   $ hg merge m
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg commit -d '11 0' -m 'merge head 2'
   $ hg heads --topo m
   changeset:   16:a58ca5d3bdf3
   branch:      m
   user:        test
   date:        Thu Jan 01 00:00:10 1970 +0000
   summary:     head 1
   
   $ hg branches
   md                            18:c914c99f1fbb
   m                             17:df343b0df04f
   b                             13:e23b5505d1ad
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
 
 partially close multihead branch
 
   $ hg up -C a58ca5d3bdf3
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg commit -d '12 0' -m 'close head 1' --close-branch
   $ hg heads --topo m
   changeset:   19:cd21a80baa3d
   branch:      m
   tag:         tip
   parent:      16:a58ca5d3bdf3
   user:        test
   date:        Thu Jan 01 00:00:12 1970 +0000
   summary:     close head 1
   
   $ hg branches
   md                            18:c914c99f1fbb
   b                             13:e23b5505d1ad
   a branch name much longer than the default justification used by branches 7:10ff5895aa57
   m                             17:df343b0df04f (inactive)
   a                              5:d8cbc61dbaa6 (inactive)
   default                        0:19709c5a4e75 (inactive)
 
 default branch colors:
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > color =
   > [color]
   > mode = ansi
   > EOF
 
   $ hg up -C b
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg branches --color=always
   \x1b[0;0mmd\x1b[0m\x1b[0;33m                            18:c914c99f1fbb\x1b[0m (esc)
   \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;0mm\x1b[0m\x1b[0;33m                             17:df343b0df04f\x1b[0m (inactive) (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;0mmd\x1b[0m\x1b[0;33m                            18:c914c99f1fbb\x1b[0m (esc)
   \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;0mm\x1b[0m\x1b[0;33m                             17:df343b0df04f\x1b[0m (inactive) (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;32mmd\x1b[0m\x1b[0;36m                            18:c914c99f1fbb\x1b[0m (esc)
   \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;35mm\x1b[0m\x1b[0;36m                             17:df343b0df04f\x1b[0m (inactive) (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;32mmd\x1b[0m\x1b[0;36m                            18:c914c99f1fbb\x1b[0m (esc)
   \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;35mm\x1b[0m\x1b[0;36m                             17:df343b0df04f\x1b[0m (inactive) (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": "md",
     "closed": false,
     "current": false,
     "node": "c914c99f1fbb2b1d785a0a939ed3f67275df18e9",
     "rev": 18
    },
    {
     "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": "m",
     "closed": false,
     "current": false,
     "node": "df343b0df04feb2a946cd4b6e9520e552fef14ee",
     "rev": 17
    },
    {
     "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
    }
   ]
 
   $ hg branches --closed -T '{if(closed, "{branch}\n")}'
   c
 
   $ hg branches -T '{word(0, branch)}: {desc|firstline}\n'
   md: merge head 2
   b: reopen branch with a change
   a: Adding d branch
   m: head 2
   a: Adding b branch head 2
   default: Adding root node
 
   $ cat <<'EOF' > "$TESTTMP/map-myjson"
   > docheader = '\{\n'
   > docfooter = '\n}\n'
   > separator = ',\n'
   > branches = ' {dict(branch, node|short)|json}'
   > EOF
   $ hg branches -T "$TESTTMP/map-myjson"
   {
    {"branch": "md", "node": "c914c99f1fbb"},
    {"branch": "b", "node": "e23b5505d1ad"},
    {"branch": "a branch *", "node": "10ff5895aa57"}, (glob)
    {"branch": "m", "node": "df343b0df04f"},
    {"branch": "a", "node": "d8cbc61dbaa6"},
    {"branch": "default", "node": "19709c5a4e75"}
   }
 
   $ cat <<'EOF' >> .hg/hgrc
   > [templates]
   > myjson = ' {dict(branch, node|short)|json}'
   > myjson:docheader = '\{\n'
   > myjson:docfooter = '\n}\n'
   > myjson:separator = ',\n'
   > EOF
   $ hg branches -T myjson
   {
    {"branch": "md", "node": "c914c99f1fbb"},
    {"branch": "b", "node": "e23b5505d1ad"},
    {"branch": "a branch *", "node": "10ff5895aa57"}, (glob)
    {"branch": "m", "node": "df343b0df04f"},
    {"branch": "a", "node": "d8cbc61dbaa6"},
    {"branch": "default", "node": "19709c5a4e75"}
   }
 
   $ cat <<'EOF' >> .hg/hgrc
   > [templates]
   > :docheader = 'should not be selected as a docheader for literal templates\n'
   > EOF
   $ hg branches -T '{branch}\n'
   md
   b
   a branch name much longer than the default justification used by branches
   m
   a
   default
 
 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-v2: size=92
   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 6d 00 6d 64             |ranches.m.md|
   .hg/cache/rbc-revs-v2: size=160
   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 f3 44 76 37 00 00 00 05 |...V.....Dv7....|
   0080: a5 8c a5 d3 00 00 00 05 df 34 3b 0d 00 00 00 05 |.........4;.....|
   0090: c9 14 c9 9f 00 00 00 06 cd 21 a8 0b 80 00 00 05 |.........!......|
 
 no errors when revbranchcache is not writable
 
   $ echo >> .hg/cache/rbc-revs-v2
   $ mv .hg/cache/rbc-revs-v2 .hg/cache/rbc-revs-v2_
   $ mkdir .hg/cache/rbc-revs-v2
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n'
   5
   $ rmdir .hg/cache/rbc-revs-v2
   $ mv .hg/cache/rbc-revs-v2_ .hg/cache/rbc-revs-v2
 
 no errors when wlock cannot be acquired
 
 #if unix-permissions
   $ mv .hg/cache/rbc-revs-v2 .hg/cache/rbc-revs-v2_
   $ rm -f .hg/cache/branch*
   $ chmod 555 .hg
   $ hg head a -T '{rev}\n'
   5
   $ chmod 755 .hg
   $ mv .hg/cache/rbc-revs-v2_ .hg/cache/rbc-revs-v2
 #endif
 
-recovery from invalid cache revs file with trailing data
-  $ echo >> .hg/cache/rbc-revs-v2
+dealing with valid cache revs file but for extra trailing data
+--------------------------------------------------------------
+
+When the trailing data are smaller than a record, they are practically
+invisible to the cache and ignored. No warning is issued about them.
+
+  $ echo '42' >> .hg/cache/rbc-revs-v2
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
-  cache/rbc-revs-v2 contains 2 unknown trailing bytes
   $ f --size .hg/cache/rbc-revs*
-  .hg/cache/rbc-revs-v2: size=162
+  .hg/cache/rbc-revs-v2: size=164
+
+When the trailing data are larger than a record, they are seens as extra
+(probably invalid) data. We warn about them when writing.
+
+  $ echo 'abracadabra!' >> .hg/cache/rbc-revs-v2
+  $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
+  5
+  cache/rbc-revs-v2 contains 17 unknown trailing bytes
+  $ f --size .hg/cache/rbc-revs*
+  .hg/cache/rbc-revs-v2: size=177
 
 recovery from invalid cache file with partial last record
+---------------------------------------------------------
   $ mv .hg/cache/rbc-revs-v2 .
   $ f -qDB 119 rbc-revs-v2 > .hg/cache/rbc-revs-v2
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v2: size=119
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   resetting content of cache/rbc-revs-v2
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v2: size=160
 
 recovery from invalid cache file with missing record - no truncation
   $ mv .hg/cache/rbc-revs-v2 .
   $ f -qDB 112 rbc-revs-v2 > .hg/cache/rbc-revs-v2
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v2: size=160
 
 recovery from invalid cache file with some bad records
   $ mv .hg/cache/rbc-revs-v2 .
   $ f -qDB 8 rbc-revs-v2 > .hg/cache/rbc-revs-v2
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v2: size=8
   $ f -qDB 112 rbc-revs-v2 >> .hg/cache/rbc-revs-v2
   $ f --size .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v2: size=120
   $ hg log -r 'branch(.)' -T '{rev} ' --debug
   history modification detected - truncating revision branch cache to revision * (glob)
   history modification detected - truncating revision branch cache to revision 1
   3 4 8 9 10 11 12 13 resetting content of cache/rbc-revs-v2
   $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
   5
   resetting content of cache/rbc-revs-v2
   $ f --size --hexdump --bytes=16 .hg/cache/rbc-revs*
   .hg/cache/rbc-revs-v2: size=160
   0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
 
 Smoothly reuse "v1" format if no v2 exists
 ------------------------------------------
 
 read only operation with valid data
 (actively rewrite data)
 
   $ rm .hg/cache/rbc-names-v2
   $ rm .hg/cache/rbc-revs-v2
   $ rm .hg/cache/branch*
   $ hg head a -T '{rev}\n' --debug
   5
   $ mv .hg/cache/rbc-names-v2 .hg/cache/rbc-names-v1
   $ mv .hg/cache/rbc-revs-v2 .hg/cache/rbc-revs-v1
   $ rm .hg/cache/branch*
   $ hg head a -T '{rev}\n' --debug
   5
   $ f --size .hg/cache/rbc-*-*
   .hg/cache/rbc-names-v1: size=92
   .hg/cache/rbc-names-v2: size=92
   .hg/cache/rbc-revs-v1: size=160
   .hg/cache/rbc-revs-v2: size=160
 
 
 Write operation write a full v2 files
 
   $ mv .hg/cache/rbc-names-v2 .hg/cache/rbc-names-v1
   $ mv .hg/cache/rbc-revs-v2 .hg/cache/rbc-revs-v1
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=92
   .hg/cache/rbc-revs-v1: size=160
   $ hg branch not-here-for-long
   marked working directory as branch not-here-for-long
   $ hg ci -m not-long --debug
   reusing manifest from p1 (no file change)
   committing changelog
   updating the branch cache
   committed changeset * (glob)
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=92
   .hg/cache/rbc-names-v2: size=110
   .hg/cache/rbc-revs-v1: size=160
   .hg/cache/rbc-revs-v2: size=168
 
 So does explicit cache upgrade
   $ mv .hg/cache/rbc-names-v2 .hg/cache/rbc-names-v1
   $ mv .hg/cache/rbc-revs-v2 .hg/cache/rbc-revs-v1
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=110
   .hg/cache/rbc-revs-v1: size=168
   $ hg debugupdatecache
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v1: size=110
   .hg/cache/rbc-names-v2: size=110
   .hg/cache/rbc-revs-v1: size=168
   .hg/cache/rbc-revs-v2: size=168
 
 With invalid v1 data, we rewrite it too (as v2)
 
   $ cp .hg/cache/rbc-names-v2 .hg/cache/rbc-names-v1
   $ mv .hg/cache/rbc-names-v2 .hg/cache/rbc-revs-v1
   $ rm .hg/cache/rbc-revs-v2
   $ rm .hg/cache/branch*
   $ 
   $ hg head a -T '{rev}\n' --debug
   history modification detected - truncating revision branch cache to revision 0
   5
   $ f --size .hg/cache/rbc-*-*
   .hg/cache/rbc-names-v1: size=110
   .hg/cache/rbc-names-v2: size=110
   .hg/cache/rbc-revs-v1: size=110
   .hg/cache/rbc-revs-v2: size=168
 
 cleanup
 
   $ hg up -qr '.^'
   $ hg rollback -qf
   $ rm .hg/cache/*
   $ hg debugupdatecache
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v2: size=92
   .hg/cache/rbc-revs-v2: size=160
 
 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-v2: size=111
   .hg/cache/rbc-revs-v2: size=168
 
 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 .hg/cache/rbc-names-*
   .hg/cache/rbc-names-v2: size=111
   $ grep "i-will-regret-this" .hg/cache/rbc-names-* > /dev/null
   $ f --size .hg/cache/rbc-revs-*
   .hg/cache/rbc-revs-v2: size=168
 
 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-v2: size=152
 
 cache is rebuilt when corruption is detected
   $ echo > .hg/cache/rbc-names-v2
   $ 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 resetting content of rbc-names-v2
   $ f --size .hg/cache/rbc-names-*
   .hg/cache/rbc-names-v2: size=84
   $ grep "i-will-regret-this" .hg/cache/rbc-names-* > /dev/null
   [1]
   $ f --size .hg/cache/rbc-revs-*
   .hg/cache/rbc-revs-v2: size=152
 
 Test that cache files are created and grows correctly:
 
   $ rm .hg/cache/rbc*
   $ hg log -r "5 & branch(5)" -T "{rev}\n"
   5
 
 (here v3 is querying branch info for heads so it warm much more of the cache)
 
 #if v2
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v2: size=1
   .hg/cache/rbc-revs-v2: size=48
 #else
   $ f --size .hg/cache/rbc-*
   .hg/cache/rbc-names-v2: size=84
   .hg/cache/rbc-revs-v2: size=152
 #endif
 
   $ 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
 
 #if v2
 
   $ f --size --sha256 .hg/cache/rbc-*
   .hg/cache/rbc-names-v2: size=14, sha256=d376f7eea9a7e28fac6470e78dae753c81a5543c9ad436e96999590e004a281c
   .hg/cache/rbc-revs-v2: size=24, sha256=ec89032fd4e66e7282cb6e403848c681a855a9c36c6b44d19179218553b78779
 
   $ : > .hg/cache/rbc-revs-v2
 
 No superfluous rebuilding of cache:
   $ hg log -r "branch(null)&branch(branch)" --debug
   $ f --size --sha256 .hg/cache/rbc-*
   .hg/cache/rbc-names-v2: size=14, sha256=d376f7eea9a7e28fac6470e78dae753c81a5543c9ad436e96999590e004a281c
   .hg/cache/rbc-revs-v2: size=24, sha256=ec89032fd4e66e7282cb6e403848c681a855a9c36c6b44d19179218553b78779
 #endif
 
   $ cd ..
 
 Test to make sure that `--close-branch` only works on a branch head:
 --------------------------------------------------------------------
   $ hg init closebranch
   $ cd closebranch
   $ for ch in a b c; do
   > echo $ch > $ch
   > hg add $ch
   > hg ci -m "added "$ch
   > done;
 
   $ hg up -r "desc('added b')"
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
 trying to close branch from a cset which is not a branch head
 it should abort:
   $ hg ci -m "closing branch" --close-branch
   abort: can only close branch heads
   (use --force-close-branch to close branch from a non-head changeset)
   [10]
 
   $ hg up 0
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg log -GT "{rev}: {node|short} {desc|firstline}\n\t{branch}\n\n"
   o  2: 155349b645be added c
   |  	default
   |
   o  1: 5f6d8a4bf34a added b
   |  	default
   |
   @  0: 9092f1db7931 added a
      	default
   
 Test --force-close-branch to close a branch from a non-head changeset:
 ---------------------------------------------------------------------
 
   $ hg show stack --config extensions.show=
     o  1553 added c
     o  5f6d added b
     @  9092 added a
 
   $ hg ci -m "branch closed" --close-branch
   abort: can only close branch heads
   (use --force-close-branch to close branch from a non-head changeset)
   [10]
 
   $ hg ci -m "branch closed" --force-close-branch
   created new head
   $ cd ..
 
 Test various special cases for the branchmap
 --------------------------------------------
 
 Basic fork of the same branch
 
   $ hg init branchmap-testing1
   $ cd branchmap-testing1
   $ hg debugbuild '@A . :base . :p1 *base /p1'
   $ hg log -G
   o    changeset:   3:71ca9a6d524e
   |\   branch:      A
   | |  tag:         tip
   | |  parent:      2:a3b807b3ff0b
   | |  parent:      1:99ba08759bc7
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:03 1970 +0000
   | |  summary:     r3
   | |
   | o  changeset:   2:a3b807b3ff0b
   | |  branch:      A
   | |  parent:      0:2ab8003a1750
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:02 1970 +0000
   | |  summary:     r2
   | |
   o |  changeset:   1:99ba08759bc7
   |/   branch:      A
   |    tag:         p1
   |    user:        debugbuilddag
   |    date:        Thu Jan 01 00:00:01 1970 +0000
   |    summary:     r1
   |
   o  changeset:   0:2ab8003a1750
      branch:      A
      tag:         base
      user:        debugbuilddag
      date:        Thu Jan 01 00:00:00 1970 +0000
      summary:     r0
   
   $ hg branches
   A                              3:71ca9a6d524e
   $ hg clone -r 1 -r 2 . ../branchmap-testing1-clone
   adding changesets
   adding manifests
   adding file changes
   added 3 changesets with 0 changes to 0 files (+1 heads)
   new changesets 2ab8003a1750:a3b807b3ff0b
   updating to branch A
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ../branchmap-testing1-clone
   $ hg pull ../branchmap-testing1
   pulling from ../branchmap-testing1
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 0 changes to 0 files (-1 heads)
   new changesets 71ca9a6d524e
   (run 'hg update' to get a working copy)
   $ hg branches
   A                              3:71ca9a6d524e
   $ cd ..
 
 Switching to a different branch and back
 
   $ hg init branchmap-testing2
   $ cd branchmap-testing2
   $ hg debugbuild '@A . @B . @A .'
   $ hg log -G
   o  changeset:   2:9699e9f260b5
   |  branch:      A
   |  tag:         tip
   |  user:        debugbuilddag
   |  date:        Thu Jan 01 00:00:02 1970 +0000
   |  summary:     r2
   |
   o  changeset:   1:0bc7d348d965
   |  branch:      B
   |  user:        debugbuilddag
   |  date:        Thu Jan 01 00:00:01 1970 +0000
   |  summary:     r1
   |
   o  changeset:   0:2ab8003a1750
      branch:      A
      user:        debugbuilddag
      date:        Thu Jan 01 00:00:00 1970 +0000
      summary:     r0
   
   $ hg branches
   A                              2:9699e9f260b5
   B                              1:0bc7d348d965 (inactive)
   $ hg clone -r 1 . ../branchmap-testing2-clone
   adding changesets
   adding manifests
   adding file changes
   added 2 changesets with 0 changes to 0 files
   new changesets 2ab8003a1750:0bc7d348d965
   updating to branch B
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ../branchmap-testing2-clone
   $ hg pull ../branchmap-testing2
   pulling from ../branchmap-testing2
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 0 changes to 0 files
   new changesets 9699e9f260b5
   (run 'hg update' to get a working copy)
   $ hg branches
   A                              2:9699e9f260b5
   B                              1:0bc7d348d965 (inactive)
   $ cd ..
 
 A fork on a branch switching to a different branch and back
 is still collecting the fork.
 
   $ hg init branchmap-testing3
   $ cd branchmap-testing3
   $ hg debugbuild '@A . :base . :p1 *base @B . @A /p1'
   $ hg log -G
   o    changeset:   4:3614a1711d23
   |\   branch:      A
   | |  tag:         tip
   | |  parent:      3:e9c8abcf65aa
   | |  parent:      1:99ba08759bc7
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:04 1970 +0000
   | |  summary:     r4
   | |
   | o  changeset:   3:e9c8abcf65aa
   | |  branch:      B
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:03 1970 +0000
   | |  summary:     r3
   | |
   | o  changeset:   2:a3b807b3ff0b
   | |  branch:      A
   | |  parent:      0:2ab8003a1750
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:02 1970 +0000
   | |  summary:     r2
   | |
   o |  changeset:   1:99ba08759bc7
   |/   branch:      A
   |    tag:         p1
   |    user:        debugbuilddag
   |    date:        Thu Jan 01 00:00:01 1970 +0000
   |    summary:     r1
   |
   o  changeset:   0:2ab8003a1750
      branch:      A
      tag:         base
      user:        debugbuilddag
      date:        Thu Jan 01 00:00:00 1970 +0000
      summary:     r0
   
   $ hg branches
   A                              4:3614a1711d23
   B                              3:e9c8abcf65aa (inactive)
   $ hg clone -r 1 -r 3 . ../branchmap-testing3-clone
   adding changesets
   adding manifests
   adding file changes
   added 4 changesets with 0 changes to 0 files (+1 heads)
   new changesets 2ab8003a1750:e9c8abcf65aa
   updating to branch A
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ../branchmap-testing3-clone
   $ hg pull ../branchmap-testing3
   pulling from ../branchmap-testing3
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 0 changes to 0 files (-1 heads)
   new changesets 3614a1711d23
   (run 'hg update' to get a working copy)
   $ hg branches
   A                              4:3614a1711d23
   B                              3:e9c8abcf65aa (inactive)
   $ cd ..
 
 Intermediary parents are on different branches.
 
   $ hg init branchmap-testing4
   $ cd branchmap-testing4
   $ hg debugbuild '@A . @B :base . @A :p1 *base @C . @A /p1'
   $ hg log -G
   o    changeset:   4:4bf67499b70a
   |\   branch:      A
   | |  tag:         tip
   | |  parent:      3:4a546028fa8f
   | |  parent:      1:0bc7d348d965
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:04 1970 +0000
   | |  summary:     r4
   | |
   | o  changeset:   3:4a546028fa8f
   | |  branch:      C
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:03 1970 +0000
   | |  summary:     r3
   | |
   | o  changeset:   2:a3b807b3ff0b
   | |  branch:      A
   | |  parent:      0:2ab8003a1750
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:02 1970 +0000
   | |  summary:     r2
   | |
   o |  changeset:   1:0bc7d348d965
   |/   branch:      B
   |    tag:         p1
   |    user:        debugbuilddag
   |    date:        Thu Jan 01 00:00:01 1970 +0000
   |    summary:     r1
   |
   o  changeset:   0:2ab8003a1750
      branch:      A
      tag:         base
      user:        debugbuilddag
      date:        Thu Jan 01 00:00:00 1970 +0000
      summary:     r0
   
   $ hg branches
   A                              4:4bf67499b70a
   C                              3:4a546028fa8f (inactive)
   B                              1:0bc7d348d965 (inactive)
   $ hg clone -r 1 -r 3 . ../branchmap-testing4-clone
   adding changesets
   adding manifests
   adding file changes
   added 4 changesets with 0 changes to 0 files (+1 heads)
   new changesets 2ab8003a1750:4a546028fa8f
   updating to branch B
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ../branchmap-testing4-clone
   $ hg pull ../branchmap-testing4
   pulling from ../branchmap-testing4
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 0 changes to 0 files (-1 heads)
   new changesets 4bf67499b70a
   (run 'hg update' to get a working copy)
   $ hg branches
   A                              4:4bf67499b70a
   C                              3:4a546028fa8f (inactive)
   B                              1:0bc7d348d965 (inactive)
   $ cd ..
 
 Check that the cache are not written too early
 ----------------------------------------------
 
   $ hg log -R branchmap-testing1 -G
   o    changeset:   3:71ca9a6d524e
   |\   branch:      A
   | |  tag:         tip
   | |  parent:      2:a3b807b3ff0b
   | |  parent:      1:99ba08759bc7
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:03 1970 +0000
   | |  summary:     r3
   | |
   | o  changeset:   2:a3b807b3ff0b
   | |  branch:      A
   | |  parent:      0:2ab8003a1750
   | |  user:        debugbuilddag
   | |  date:        Thu Jan 01 00:00:02 1970 +0000
   | |  summary:     r2
   | |
   o |  changeset:   1:99ba08759bc7
   |/   branch:      A
   |    tag:         p1
   |    user:        debugbuilddag
   |    date:        Thu Jan 01 00:00:01 1970 +0000
   |    summary:     r1
   |
   o  changeset:   0:2ab8003a1750
      branch:      A
      tag:         base
      user:        debugbuilddag
      date:        Thu Jan 01 00:00:00 1970 +0000
      summary:     r0
   
   $ hg bundle -R branchmap-testing1 --base 1 bundle.hg --rev 'head()'
   2 changesets found
 
 Unbundling revision should warm the served cache
 
   $ hg clone branchmap-testing1 --rev 1 branchmap-update-01
   adding changesets
   adding manifests
   adding file changes
   added 2 changesets with 0 changes to 0 files
   new changesets 2ab8003a1750:99ba08759bc7
   updating to branch A
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
 #if v3
   $ cat branchmap-update-01/.hg/cache/branch3-exp-base
   tip-node=99ba08759bc7f6fdbe5304e83d0387f35c082479 tip-rev=1 topo-mode=pure
   A
 #else
   $ cat branchmap-update-01/.hg/cache/branch2-base
   99ba08759bc7f6fdbe5304e83d0387f35c082479 1
   99ba08759bc7f6fdbe5304e83d0387f35c082479 o A
 #endif
   $ hg -R branchmap-update-01 unbundle bundle.hg
   adding changesets
   adding manifests
   adding file changes
   added 2 changesets with 0 changes to 0 files
   new changesets a3b807b3ff0b:71ca9a6d524e (2 drafts)
   (run 'hg update' to get a working copy)
 #if v3
   $ cat branchmap-update-01/.hg/cache/branch3-exp-served
   tip-node=71ca9a6d524ed3c2a215119b2086ac3b8c4c8286 tip-rev=3 topo-mode=pure
   A
 #else
   $ cat branchmap-update-01/.hg/cache/branch2-served
   71ca9a6d524ed3c2a215119b2086ac3b8c4c8286 3
   71ca9a6d524ed3c2a215119b2086ac3b8c4c8286 o A
 #endif
 
 aborted Unbundle should not update the on disk cache
 
   $ cat >> simplehook.py << EOF
   > import sys
   > from mercurial import node
   > from mercurial import branchmap
   > def hook(ui, repo, *args, **kwargs):
   >     s = repo.filtered(b"served")
   >     s.branchmap()
   >     return 1
   > EOF
   $ hg clone branchmap-testing1 --rev 1 branchmap-update-02
   adding changesets
   adding manifests
   adding file changes
   added 2 changesets with 0 changes to 0 files
   new changesets 2ab8003a1750:99ba08759bc7
   updating to branch A
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 #if v3
   $ cat branchmap-update-02/.hg/cache/branch3-exp-base
   tip-node=99ba08759bc7f6fdbe5304e83d0387f35c082479 tip-rev=1 topo-mode=pure
   A
 #else
   $ cat branchmap-update-02/.hg/cache/branch2-base
   99ba08759bc7f6fdbe5304e83d0387f35c082479 1
   99ba08759bc7f6fdbe5304e83d0387f35c082479 o A
 #endif
   $ hg -R branchmap-update-02 unbundle bundle.hg --config "hooks.pretxnclose=python:$TESTTMP/simplehook.py:hook"
   adding changesets
   adding manifests
   adding file changes
   transaction abort!
   rollback completed
   abort: pretxnclose hook failed
   [40]
 #if v3
   $ cat branchmap-update-02/.hg/cache/branch3-exp-base
   tip-node=99ba08759bc7f6fdbe5304e83d0387f35c082479 tip-rev=1 topo-mode=pure
   A
 #else
   $ cat branchmap-update-02/.hg/cache/branch2-base
   99ba08759bc7f6fdbe5304e83d0387f35c082479 1
   99ba08759bc7f6fdbe5304e83d0387f35c082479 o A
 #endif