annotate tests/test-branches.t @ 24545:9e0c67e84896

json: implement {tags} template

Tags is pretty easy to implement. Let's start there.

The output is slightly different from `hg tags -Tjson`. For reference,
the CLI has the following output:

  [
   {
    "node": "e2049974f9a23176c2addb61d8f5b86e0d620490",
    "rev": 29880,
    "tag": "tip",
    "type": ""
   },
   ...
  ]

Our output has the format:

  {
    "node": "0aeb19ea57a6d223bacddda3871cb78f24b06510",
    "tags": [
      {
        "node": "e2049974f9a23176c2addb61d8f5b86e0d620490",
        "tag": "tag1",
        "date": [1427775457.0, 25200]
      },
      ...
    ]
  }

"rev" is omitted because it isn't a reliable identifier. We shouldn't
be exposing them in web APIs and giving the impression it remotely
resembles a stable identifier. Perhaps we could one day hide this behind
a config option (it might be useful to expose when running servers
locally).

The "type" of the tag isn't defined because this information isn't yet
exposed to the hgweb templater (it could be in a follow-up) and because
it is questionable whether different types should be exposed at all.
(Should the web interface really be exposing "local" tags?)

We use an object for the outer type instead of Array for a few reasons.
First, it is extensible. If we ever need to throw more global properties
into the output, we can do that without breaking backwards compatibility
(property additions should be backwards compatible). Second, uniformity
in web APIs is nice. Having everything return objects seems much saner than
a mix of array and object. Third, there are security issues with arrays
in older browsers. The JSON web services world almost never uses arrays
as the main type for this reason.

Another possibly controversial part about this patch is how dates are
defined. While JSON has a Date type, it is based on the JavaScript Date
type, which is widely considered a pile of garbage. It is a non-starter
for this reason.

Many of Mercurial's built-in date filters drop seconds resolution. So
that's a non-starter as well, since we want the API to be lossless where
possible. rfc3339date, rfc822date, isodatesec, and date are all lossless.
However, they each require the client to perform string parsing on top of
JSON decoding. While date parsing libraries are pretty ubiquitous, some
languages don't have them out of the box. However, pretty much every
programming language can deal with UNIX timestamps (which are just
integers or floats). So, we choose to use Mercurial's internal date
representation, which in JSON is modeled as float seconds since UNIX
epoch and an integer timezone offset from UTC (keep in mind
JavaScript/JSON models all "Numbers" as double prevision floating point
numbers, so there isn't a difference between ints and floats in JSON).

  $ hg init a
  $ cd a
  $ echo 'root' >root
  $ hg add root
  $ hg commit -d '0 0' -m "Adding root node"

  $ echo 'a' >a
  $ hg add a
  $ hg branch a
  marked working directory as branch a
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -d '1 0' -m "Adding a branch"

  $ hg branch q
  marked working directory as branch q
  (branches are permanent and global, did you want a bookmark?)
  $ 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
  (branches are permanent and global, did you want a bookmark?)
  $ 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
  (branches are permanent and global, did you want a bookmark?)
  $ 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
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -d '6 0' -m "Adding d branch"

  $ hg branches
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  b                              4:aee39cd168d0
  c                              6:589736a22561 (inactive)
  a                              5:d8cbc61dbaa6 (inactive)
  default                        0:19709c5a4e75 (inactive)

-------

  $ hg branches -a
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  b                              4:aee39cd168d0

--- Branch a

  $ hg log -b a
  changeset:   5:d8cbc61dbaa6
  branch:      a
  parent:      2:881fe2b92ad0
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     Adding b branch head 2
  
  changeset:   2:881fe2b92ad0
  branch:      a
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     Adding to a branch
  
  changeset:   1:dd6b440dd85a
  branch:      a
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     Adding a branch
  

---- Branch b

  $ hg log -b b
  changeset:   4:aee39cd168d0
  branch:      b
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     Adding b branch head 1
  
  changeset:   3:ac22033332d1
  branch:      b
  parent:      0:19709c5a4e75
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     Adding b branch
  

---- going to test branch closing

  $ hg branches
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  b                              4:aee39cd168d0
  c                              6:589736a22561 (inactive)
  a                              5:d8cbc61dbaa6 (inactive)
  default                        0:19709c5a4e75 (inactive)
  $ hg up -C b
  2 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ echo 'xxx1' >> b
  $ hg commit -d '7 0' -m 'adding cset to branch b'
  $ hg up -C aee39cd168d0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo 'xxx2' >> b
  $ hg commit -d '8 0' -m 'adding head to branch b'
  created new head
  $ echo 'xxx3' >> b
  $ hg commit -d '9 0' -m 'adding another cset to branch b'
  $ hg branches
  b                             10:bfbe841b666e
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  c                              6:589736a22561 (inactive)
  a                              5:d8cbc61dbaa6 (inactive)
  default                        0:19709c5a4e75 (inactive)
  $ hg heads --closed
  changeset:   10:bfbe841b666e
  branch:      b
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     adding another cset to branch b
  
  changeset:   8:eebb944467c9
  branch:      b
  parent:      4:aee39cd168d0
  user:        test
  date:        Thu Jan 01 00:00:07 1970 +0000
  summary:     adding cset to branch b
  
  changeset:   7:10ff5895aa57
  branch:      a branch name much longer than the default justification used by branches
  user:        test
  date:        Thu Jan 01 00:00:06 1970 +0000
  summary:     Adding d branch
  
  changeset:   6:589736a22561
  branch:      c
  user:        test
  date:        Thu Jan 01 00:00:05 1970 +0000
  summary:     Adding c branch
  
  changeset:   5:d8cbc61dbaa6
  branch:      a
  parent:      2:881fe2b92ad0
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     Adding b branch head 2
  
  changeset:   0:19709c5a4e75
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Adding root node
  
  $ hg heads
  changeset:   10:bfbe841b666e
  branch:      b
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     adding another cset to branch b
  
  changeset:   8:eebb944467c9
  branch:      b
  parent:      4:aee39cd168d0
  user:        test
  date:        Thu Jan 01 00:00:07 1970 +0000
  summary:     adding cset to branch b
  
  changeset:   7:10ff5895aa57
  branch:      a branch name much longer than the default justification used by branches
  user:        test
  date:        Thu Jan 01 00:00:06 1970 +0000
  summary:     Adding d branch
  
  changeset:   6:589736a22561
  branch:      c
  user:        test
  date:        Thu Jan 01 00:00:05 1970 +0000
  summary:     Adding c branch
  
  changeset:   5:d8cbc61dbaa6
  branch:      a
  parent:      2:881fe2b92ad0
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     Adding b branch head 2
  
  changeset:   0:19709c5a4e75
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Adding root node
  
  $ hg commit -d '9 0' --close-branch -m 'prune bad branch'
  $ hg branches -a
  b                              8:eebb944467c9
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  $ hg up -C b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg commit -d '9 0' --close-branch -m 'close this part branch too'
  $ hg commit -d '9 0' --close-branch -m 're-closing this branch'
  abort: can only close branch heads
  [255]

  $ hg log -r tip --debug
  changeset:   12:e3d49c0575d8fc2cb1cd6859c747c14f5f6d499f
  branch:      b
  tag:         tip
  phase:       draft
  parent:      8:eebb944467c9fb9651ed232aeaf31b3c0a7fc6c1
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    8:6f9ed32d2b310e391a4f107d5f0f071df785bfee
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  extra:       branch=b
  extra:       close=1
  description:
  close this part branch too
  
  
--- b branch should be inactive

  $ hg branches
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  c                              6:589736a22561 (inactive)
  a                              5:d8cbc61dbaa6 (inactive)
  default                        0:19709c5a4e75 (inactive)
  $ hg branches -c
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  b                             12:e3d49c0575d8 (closed)
  c                              6:589736a22561 (inactive)
  a                              5:d8cbc61dbaa6 (inactive)
  default                        0:19709c5a4e75 (inactive)
  $ hg branches -a
  a branch name much longer than the default justification used by branches 7:10ff5895aa57
  $ hg branches -q
  a branch name much longer than the default justification used by branches
  c
  a
  default
  $ hg heads b
  no open branch heads found on branches b
  [1]
  $ hg heads --closed b
  changeset:   12:e3d49c0575d8
  branch:      b
  tag:         tip
  parent:      8:eebb944467c9
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     close this part branch too
  
  changeset:   11:d3f163457ebf
  branch:      b
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     prune bad branch
  
  $ echo 'xxx4' >> b
  $ hg commit -d '9 0' -m 'reopen branch with a change'
  reopening closed branch head 12

--- branch b is back in action

  $ hg branches -a
  b                             13:e23b5505d1ad
  a branch name much longer than the default justification used by branches 7:10ff5895aa57

---- test heads listings

  $ hg heads
  changeset:   13:e23b5505d1ad
  branch:      b
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     reopen branch with a change
  
  changeset:   7:10ff5895aa57
  branch:      a branch name much longer than the default justification used by branches
  user:        test
  date:        Thu Jan 01 00:00:06 1970 +0000
  summary:     Adding d branch
  
  changeset:   6:589736a22561
  branch:      c
  user:        test
  date:        Thu Jan 01 00:00:05 1970 +0000
  summary:     Adding c branch
  
  changeset:   5:d8cbc61dbaa6
  branch:      a
  parent:      2:881fe2b92ad0
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     Adding b branch head 2
  
  changeset:   0:19709c5a4e75
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Adding root node
  

branch default

  $ hg heads default
  changeset:   0:19709c5a4e75
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Adding root node
  

branch a

  $ hg heads a
  changeset:   5:d8cbc61dbaa6
  branch:      a
  parent:      2:881fe2b92ad0
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     Adding b branch head 2
  
  $ hg heads --active a
  no open branch heads found on branches a
  [1]

branch b

  $ hg heads b
  changeset:   13:e23b5505d1ad
  branch:      b
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     reopen branch with a change
  
  $ hg heads --closed b
  changeset:   13:e23b5505d1ad
  branch:      b
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     reopen branch with a change
  
  changeset:   11:d3f163457ebf
  branch:      b
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     prune bad branch
  
default branch colors:

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > color =
  > [color]
  > mode = ansi
  > EOF

  $ hg up -C c
  3 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg commit -d '9 0' --close-branch -m 'reclosing this branch'
  $ hg up -C b
  2 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ hg branches --color=always
  \x1b[0;32mb\x1b[0m\x1b[0;33m                             13:e23b5505d1ad\x1b[0m (esc)
  \x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;33m 7:10ff5895aa57\x1b[0m (esc)
  \x1b[0;0ma\x1b[0m\x1b[0;33m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
  \x1b[0;0mdefault\x1b[0m\x1b[0;33m                        0:19709c5a4e75\x1b[0m (inactive) (esc)

default closed branch color:

  $ hg branches --color=always --closed
  \x1b[0;32mb\x1b[0m\x1b[0;33m                             13:e23b5505d1ad\x1b[0m (esc)
  \x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;33m 7:10ff5895aa57\x1b[0m (esc)
  \x1b[0;30;1mc\x1b[0m\x1b[0;33m                             14:f894c25619d3\x1b[0m (closed) (esc)
  \x1b[0;0ma\x1b[0m\x1b[0;33m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
  \x1b[0;0mdefault\x1b[0m\x1b[0;33m                        0:19709c5a4e75\x1b[0m (inactive) (esc)

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > color =
  > [color]
  > branches.active = green
  > branches.closed = blue
  > branches.current = red
  > branches.inactive = magenta
  > log.changeset = cyan
  > EOF

custom branch colors:

  $ hg branches --color=always
  \x1b[0;31mb\x1b[0m\x1b[0;36m                             13:e23b5505d1ad\x1b[0m (esc)
  \x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;36m 7:10ff5895aa57\x1b[0m (esc)
  \x1b[0;35ma\x1b[0m\x1b[0;36m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
  \x1b[0;35mdefault\x1b[0m\x1b[0;36m                        0:19709c5a4e75\x1b[0m (inactive) (esc)

custom closed branch color:

  $ hg branches --color=always --closed
  \x1b[0;31mb\x1b[0m\x1b[0;36m                             13:e23b5505d1ad\x1b[0m (esc)
  \x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;36m 7:10ff5895aa57\x1b[0m (esc)
  \x1b[0;34mc\x1b[0m\x1b[0;36m                             14:f894c25619d3\x1b[0m (closed) (esc)
  \x1b[0;35ma\x1b[0m\x1b[0;36m                              5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
  \x1b[0;35mdefault\x1b[0m\x1b[0;36m                        0:19709c5a4e75\x1b[0m (inactive) (esc)

template output:

  $ hg branches -Tjson --closed
  [
   {
    "active": true,
    "branch": "b",
    "closed": false,
    "current": true,
    "node": "e23b5505d1ad24aab6f84fd8c7cb8cd8e5e93be0",
    "rev": 13
   },
   {
    "active": true,
    "branch": "a branch name much longer than the default justification used by branches",
    "closed": false,
    "current": false,
    "node": "10ff5895aa5793bd378da574af8cec8ea408d831",
    "rev": 7
   },
   {
    "active": false,
    "branch": "c",
    "closed": true,
    "current": false,
    "node": "f894c25619d3f1484639d81be950e0a07bc6f1f6",
    "rev": 14
   },
   {
    "active": false,
    "branch": "a",
    "closed": false,
    "current": false,
    "node": "d8cbc61dbaa6dc817175d1e301eecb863f280832",
    "rev": 5
   },
   {
    "active": false,
    "branch": "default",
    "closed": false,
    "current": false,
    "node": "19709c5a4e75bf938f8e349aff97438539bb729e",
    "rev": 0
   }
  ]


Tests of revision branch name caching

We rev branch cache is updated automatically. In these tests we use a trick to
trigger rebuilds. We remove the branch head cache and run 'hg head' to cause a
rebuild that also will populate the rev branch cache.

revision branch cache is created when building the branch head cache
  $ rm -rf .hg/cache; hg head a -T '{rev}\n'
  5
  $ f --hexdump --size .hg/cache/rbc-*
  .hg/cache/rbc-names-v1: size=87
  0000: 64 65 66 61 75 6c 74 00 61 00 62 00 63 00 61 20 |default.a.b.c.a |
  0010: 62 72 61 6e 63 68 20 6e 61 6d 65 20 6d 75 63 68 |branch name much|
  0020: 20 6c 6f 6e 67 65 72 20 74 68 61 6e 20 74 68 65 | longer than the|
  0030: 20 64 65 66 61 75 6c 74 20 6a 75 73 74 69 66 69 | default justifi|
  0040: 63 61 74 69 6f 6e 20 75 73 65 64 20 62 79 20 62 |cation used by b|
  0050: 72 61 6e 63 68 65 73                            |ranches|
  .hg/cache/rbc-revs-v1: size=120
  0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
  0010: 88 1f e2 b9 00 00 00 01 ac 22 03 33 00 00 00 02 |.........".3....|
  0020: ae e3 9c d1 00 00 00 02 d8 cb c6 1d 00 00 00 01 |................|
  0030: 58 97 36 a2 00 00 00 03 10 ff 58 95 00 00 00 04 |X.6.......X.....|
  0040: ee bb 94 44 00 00 00 02 5f 40 61 bb 00 00 00 02 |...D...._@a.....|
  0050: bf be 84 1b 00 00 00 02 d3 f1 63 45 80 00 00 02 |..........cE....|
  0060: e3 d4 9c 05 80 00 00 02 e2 3b 55 05 00 00 00 02 |.........;U.....|
  0070: f8 94 c2 56 80 00 00 03                         |...V....|

#if unix-permissions no-root
no errors when revbranchcache is not writable

  $ echo >> .hg/cache/rbc-revs-v1
  $ chmod a-w .hg/cache/rbc-revs-v1
  $ rm -f .hg/cache/branch* && hg head a -T '{rev}\n'
  5
  $ chmod a+w .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
  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
  (branches are permanent and global, did you want a bookmark?)
  $ 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

  $ cd ..