comparison tests/test-branches.t @ 29615:a2a380e2750f stable

rbc: fix superfluous rebuilding from scratch - don't abuse self._rbcnamescount

The code used self._rbcnamescount as if it was the length of self._names ...
but actually it is just the number of good entries on disk. This caused the
cache to be populated inefficiently. In some cases very inefficiently.

Instead of checking the length before lookup, just try a lookup in self._names
- that is also in most cases faster.

Comments and debug messages are tweaked to help understanding the issue
and the fix.

29614:5c79bae8166f

  .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=112

cache is rebuilt when corruption is detected
  $ echo > .hg/cache/rbc-names-v1
  $ hg log -r '5:&branch(.)' -T '{rev} ' --debug
  rebuilding corrupted revision branch cache
  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 |

  .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

  $ hg log -r "branch(null)&branch(branch)" --debug
  rebuilding corrupted revision branch cache
  rebuilding corrupted revision branch cache
  truncating cache/rbc-revs-v1 to 8
BUG: the cache was declared corrupt multiple times and not fully rebuilt:
  $ 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: 00 00 00 00 00 00 00 00 fa 4c 04 e5 00 00 00 00 |.........L......|
  0010: 56 46 78 69 00 00 00 01                         |VFxi....|

  $ cd ..

29615:a2a380e2750f

  .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=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 |

  .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 ..