view tests/test-branches.t @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

  $ 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
  [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
   }
  ]

  $ hg branches --closed -T '{if(closed, "{branch}\n")}'
  c

  $ hg branches -T '{word(0, branch)}: {desc|firstline}\n'
  b: reopen branch with a change
  a: Adding d branch
  a: Adding b branch head 2
  default: Adding root node

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 ..