view tests/test-tags.t @ 30155:b7a966ce89ed

changelog: disable delta chains

This patch disables delta chains on changelogs. After this patch, new
entries on changelogs - including existing changelogs - will be stored
as the fulltext of that data (likely compressed). No delta computation
will be performed.

An overview of delta chains and data justifying this change follows.

Revlogs try to store entries as a delta against a previous entry (either
a parent revision in the case of generaldelta or the previous physical
revision when not using generaldelta). Most of the time this is the
correct thing to do: it frequently results in less CPU usage and smaller
storage.

Delta chains are most effective when the base revision being deltad
against is similar to the current data. This tends to occur naturally
for manifests and file data, since only small parts of each tend to
change with each revision. Changelogs, however, are a different story.

Changelog entries represent changesets/commits. And unless commits in a
repository are homogonous (same author, changing same files, similar
commit messages, etc), a delta from one entry to the next tends to be
relatively large compared to the size of the entry. This means that
delta chains tend to be short. How short? Here is the full vs delta
revision breakdown on some real world repos:

Repo             % Full    % Delta   Max Length
hg                45.8       54.2        6
mozilla-central   42.4       57.6        8
mozilla-unified   42.5       57.5       17
pypy              46.1       53.9        6
python-zstandard  46.1       53.9        3

(I threw in python-zstandard as an example of a repo that is homogonous.
It contains a small Python project with changes all from the same
author.)

Contrast this with the manifest revlog for these repos, where 99+% of
revisions are deltas and delta chains run into the thousands.

So delta chains aren't as useful on changelogs. But even a short delta
chain may provide benefits. Let's measure that.

Delta chains may require less CPU to read revisions if the CPU time
spent reading smaller deltas is less than the CPU time used to
decompress larger individual entries. We can measure this via
`hg perfrevlog -c -d 1` to iterate a revlog to resolve each revision's
fulltext. Here are the results of that command on a repo using delta
chains in its changelog and on a repo without delta chains:

hg (forward)
! wall 0.407008 comb 0.410000 user 0.410000 sys 0.000000 (best of 25)
! wall 0.390061 comb 0.390000 user 0.390000 sys 0.000000 (best of 26)

hg (reverse)
! wall 0.515221 comb 0.520000 user 0.520000 sys 0.000000 (best of 19)
! wall 0.400018 comb 0.400000 user 0.390000 sys 0.010000 (best of 25)

mozilla-central (forward)
! wall 4.508296 comb 4.490000 user 4.490000 sys 0.000000 (best of 3)
! wall 4.370222 comb 4.370000 user 4.350000 sys 0.020000 (best of 3)

mozilla-central (reverse)
! wall 5.758995 comb 5.760000 user 5.720000 sys 0.040000 (best of 3)
! wall 4.346503 comb 4.340000 user 4.320000 sys 0.020000 (best of 3)

mozilla-unified (forward)
! wall 4.957088 comb 4.950000 user 4.940000 sys 0.010000 (best of 3)
! wall 4.660528 comb 4.650000 user 4.630000 sys 0.020000 (best of 3)

mozilla-unified (reverse)
! wall 6.119827 comb 6.110000 user 6.090000 sys 0.020000 (best of 3)
! wall 4.675136 comb 4.670000 user 4.670000 sys 0.000000 (best of 3)

pypy (forward)
! wall 1.231122 comb 1.240000 user 1.230000 sys 0.010000 (best of 8)
! wall 1.164896 comb 1.160000 user 1.160000 sys 0.000000 (best of 9)

pypy (reverse)
! wall 1.467049 comb 1.460000 user 1.460000 sys 0.000000 (best of 7)
! wall 1.160200 comb 1.170000 user 1.160000 sys 0.010000 (best of 9)

The data clearly shows that it takes less wall and CPU time to resolve
revisions when there are no delta chains in the changelogs, regardless
of the direction of traversal. Furthermore, not using a delta chain
means that fulltext resolution in reverse is as fast as iterating
forward. So not using delta chains on the changelog is a clear CPU win
for reading operations.

An example of a user-visible operation showing this speed-up is revset
evaluation. Here are results for
`hg perfrevset 'author(gps) or author(mpm)'`:

hg
! wall 1.655506 comb 1.660000 user 1.650000 sys 0.010000 (best of 6)
! wall 1.612723 comb 1.610000 user 1.600000 sys 0.010000 (best of 7)

mozilla-central
! wall 17.629826 comb 17.640000 user 17.600000 sys 0.040000 (best of 3)
! wall 17.311033 comb 17.300000 user 17.260000 sys 0.040000 (best of 3)

What about 00changelog.i size?

Repo                Delta Chains     No Delta Chains
hg                    7,033,250         6,976,771
mozilla-central      82,978,748        81,574,623
mozilla-unified      88,112,349        86,702,162
pypy                 20,740,699        20,659,741

The data shows that removing delta chains from the changelog makes the
changelog smaller.

Delta chains are also used during changegroup generation. This
operation essentially converts a series of revisions to one large
delta chain. And changegroup generation is smart: if the delta in
the revlog matches what the changegroup is emitting, it will reuse
the delta instead of recalculating it. We can measure the impact
removing changelog delta chains has on changegroup generation via
`hg perfchangegroupchangelog`:

hg
! wall 1.589245 comb 1.590000 user 1.590000 sys 0.000000 (best of 7)
! wall 1.788060 comb 1.790000 user 1.790000 sys 0.000000 (best of 6)

mozilla-central
! wall 17.382585 comb 17.380000 user 17.340000 sys 0.040000 (best of 3)
! wall 20.161357 comb 20.160000 user 20.120000 sys 0.040000 (best of 3)

mozilla-unified
! wall 18.722839 comb 18.720000 user 18.680000 sys 0.040000 (best of 3)
! wall 21.168075 comb 21.170000 user 21.130000 sys 0.040000 (best of 3)

pypy
! wall 4.828317 comb 4.830000 user 4.820000 sys 0.010000 (best of 3)
! wall 5.415455 comb 5.420000 user 5.410000 sys 0.010000 (best of 3)

The data shows eliminating delta chains makes the changelog part of
changegroup generation slower. This is expected since we now have to
compute deltas for revisions where we could recycle the delta before.

It is worth putting this regression into context of overall changegroup
times. Here is the rough total CPU time spent in changegroup generation
for various repos while using delta chains on the changelog:

Repo              CPU Time (s)    CPU Time w/ compression
hg                  4.50              7.05
mozilla-central   111.1             222.0
pypy               28.68             75.5

Before compression, removing delta chains from the changegroup adds
~4.4% overhead to hg changegroup generation, 1.3% to mozilla-central,
and 2.0% to pypy. When you factor in zlib compression, these percentages
are roughly divided by 2.

While the increased CPU usage for changegroup generation is unfortunate,
I think it is acceptable because the percentage is small, server
operators (those likely impacted most by this) have other mechanisms
to mitigate CPU consumption (namely reducing zlib compression level and
pre-generated clone bundles), and because there is room to optimize this
in the future. For example, we could use the nullid as the base revision,
effectively encoding the full revision for each entry in the changegroup.
When doing this, `hg perfchangegroupchangelog` nearly halves:

mozilla-unified
! wall 21.168075 comb 21.170000 user 21.130000 sys 0.040000 (best of 3)
! wall 11.196461 comb 11.200000 user 11.190000 sys 0.010000 (best of 3)

This looks very promising as a future optimization opportunity.

It's worth that the changes in test-acl.t to the changegroup part size.
This is because revision 6 in the changegroup had a delta chain of
length 2 before and after this patch the base revision is nullrev.
When the base revision is nullrev, cg2packer.deltaparent() hardcodes
the *previous* revision from the changegroup as the delta parent.
This caused the delta in the changegroup to switch base revisions,
the delta to change, and the size to change accordingly. While the
size increased in this case, I think sizes will remain the same
on average, as the delta base for changelog revisions doesn't matter
too much (as this patch shows). So, I don't consider this a regression.

setup

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > blackbox=
  > mock=$TESTDIR/mockblackbox.py
  > EOF

Helper functions:

  $ cacheexists() {
  >   [ -f .hg/cache/tags2-visible ] && echo "tag cache exists" || echo "no tag cache"
  > }

  $ fnodescacheexists() {
  >   [ -f .hg/cache/hgtagsfnodes1 ] && echo "fnodes cache exists" || echo "no fnodes cache"
  > }

  $ dumptags() {
  >     rev=$1
  >     echo "rev $rev: .hgtags:"
  >     hg cat -r$rev .hgtags
  > }

# XXX need to test that the tag cache works when we strip an old head
# and add a new one rooted off non-tip: i.e. node and rev of tip are the
# same, but stuff has changed behind tip.

Setup:

  $ hg init t
  $ cd t
  $ cacheexists
  no tag cache
  $ fnodescacheexists
  no fnodes cache
  $ hg id
  000000000000 tip
  $ cacheexists
  no tag cache
  $ fnodescacheexists
  no fnodes cache
  $ echo a > a
  $ hg add a
  $ hg commit -m "test"
  $ hg co
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg identify
  acb14030fe0a tip
  $ hg identify -r 'wdir()'
  acb14030fe0a tip
  $ cacheexists
  tag cache exists
No fnodes cache because .hgtags file doesn't exist
(this is an implementation detail)
  $ fnodescacheexists
  no fnodes cache

Try corrupting the cache

  $ printf 'a b' > .hg/cache/tags2-visible
  $ hg identify
  acb14030fe0a tip
  $ cacheexists
  tag cache exists
  $ fnodescacheexists
  no fnodes cache
  $ hg identify
  acb14030fe0a tip

Create local tag with long name:

  $ T=`hg identify --debug --id`
  $ hg tag -l "This is a local tag with a really long name!"
  $ hg tags
  tip                                0:acb14030fe0a
  This is a local tag with a really long name!     0:acb14030fe0a
  $ rm .hg/localtags

Create a tag behind hg's back:

  $ echo "$T first" > .hgtags
  $ cat .hgtags
  acb14030fe0a21b60322c440ad2d20cf7685a376 first
  $ hg add .hgtags
  $ hg commit -m "add tags"
  $ hg tags
  tip                                1:b9154636be93
  first                              0:acb14030fe0a
  $ hg identify
  b9154636be93 tip

We should have a fnodes cache now that we have a real tag
The cache should have an empty entry for rev 0 and a valid entry for rev 1.


  $ fnodescacheexists
  fnodes cache exists
  $ f --size --hexdump .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=48
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
  0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|

Repeat with cold tag cache:

  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
  $ hg identify
  b9154636be93 tip

  $ fnodescacheexists
  fnodes cache exists
  $ f --size --hexdump .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=48
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
  0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|

And again, but now unable to write tag cache or lock file:

#if unix-permissions
  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
  $ chmod 555 .hg/cache
  $ hg identify
  b9154636be93 tip
  $ chmod 755 .hg/cache

  $ chmod 555 .hg
  $ hg identify
  b9154636be93 tip
  $ chmod 755 .hg
#endif

Tag cache debug info written to blackbox log

  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
  $ hg identify
  b9154636be93 tip
  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> writing 48 bytes to cache/hgtagsfnodes1
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> 0/1 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> blackbox -l 6

Failure to acquire lock results in no write

  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
  $ echo 'foo:1' > .hg/wlock
  $ hg identify
  b9154636be93 tip
  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> not writing .hg/cache/hgtagsfnodes1 because lock cannot be acquired
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> 0/1 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> identify exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @b9154636be938d3d431e75a7c906504a079bfe07 (5000)> blackbox -l 6

  $ fnodescacheexists
  no fnodes cache

  $ rm .hg/wlock

  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
  $ hg identify
  b9154636be93 tip

Create a branch:

  $ echo bb > a
  $ hg status
  M a
  $ hg identify
  b9154636be93+ tip
  $ hg co first
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg id
  acb14030fe0a+ first
  $ hg id -r 'wdir()'
  acb14030fe0a+ first
  $ hg -v id
  acb14030fe0a+ first
  $ hg status
  M a
  $ echo 1 > b
  $ hg add b
  $ hg commit -m "branch"
  created new head

Creating a new commit shouldn't append the .hgtags fnodes cache until
tags info is accessed

  $ f --size --hexdump .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=48
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
  0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|

  $ hg id
  c8edf04160c7 tip

First 4 bytes of record 3 are changeset fragment

  $ f --size --hexdump .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=72
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff b9 15 46 36 26 b7 b4 a7 |..........F6&...|
  0020: 73 e0 9e e3 c5 2f 51 0e 19 e0 5e 1f f9 66 d8 59 |s..../Q...^..f.Y|
  0030: c8 ed f0 41 00 00 00 00 00 00 00 00 00 00 00 00 |...A............|
  0040: 00 00 00 00 00 00 00 00                         |........|

Merge the two heads:

  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg blackbox -l3
  1970/01/01 00:00:00 bob @c8edf04160c7f731e4589d66ab3ab3486a64ac28 (5000)> merge 1
  1970/01/01 00:00:00 bob @c8edf04160c7f731e4589d66ab3ab3486a64ac28+b9154636be938d3d431e75a7c906504a079bfe07 (5000)> merge 1 exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @c8edf04160c7f731e4589d66ab3ab3486a64ac28+b9154636be938d3d431e75a7c906504a079bfe07 (5000)> blackbox -l3
  $ hg id
  c8edf04160c7+b9154636be93+ tip
  $ hg status
  M .hgtags
  $ hg commit -m "merge"

Create a fake head, make sure tag not visible afterwards:

  $ cp .hgtags tags
  $ hg tag last
  $ hg rm .hgtags
  $ hg commit -m "remove"

  $ mv tags .hgtags
  $ hg add .hgtags
  $ hg commit -m "readd"
  $ 
  $ hg tags
  tip                                6:35ff301afafe
  first                              0:acb14030fe0a

Add invalid tags:

  $ echo "spam" >> .hgtags
  $ echo >> .hgtags
  $ echo "foo bar" >> .hgtags
  $ echo "a5a5 invalid" >> .hg/localtags
  $ cat .hgtags
  acb14030fe0a21b60322c440ad2d20cf7685a376 first
  spam
  
  foo bar
  $ hg commit -m "tags"

Report tag parse error on other head:

  $ hg up 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo 'x y' >> .hgtags
  $ hg commit -m "head"
  created new head

  $ hg tags --debug
  .hgtags@75d9f02dfe28, line 2: cannot parse entry
  .hgtags@75d9f02dfe28, line 4: node 'foo' is not well formed
  .hgtags@c4be69a18c11, line 2: node 'x' is not well formed
  tip                                8:c4be69a18c11e8bc3a5fdbb576017c25f7d84663
  first                              0:acb14030fe0a21b60322c440ad2d20cf7685a376
  $ hg tip
  changeset:   8:c4be69a18c11
  tag:         tip
  parent:      3:ac5e980c4dc0
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     head
  

Test tag precedence rules:

  $ cd ..
  $ hg init t2
  $ cd t2
  $ echo foo > foo
  $ hg add foo
  $ hg ci -m 'add foo'      # rev 0
  $ hg tag bar              # rev 1
  $ echo >> foo
  $ hg ci -m 'change foo 1' # rev 2
  $ hg up -C 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg tag -r 1 -f bar      # rev 3
  $ hg up -C 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo >> foo
  $ hg ci -m 'change foo 2' # rev 4
  created new head
  $ hg tags
  tip                                4:0c192d7d5e6b
  bar                                1:78391a272241

Repeat in case of cache effects:

  $ hg tags
  tip                                4:0c192d7d5e6b
  bar                                1:78391a272241

Detailed dump of tag info:

  $ hg heads -q             # expect 4, 3, 2
  4:0c192d7d5e6b
  3:6fa450212aeb
  2:7a94127795a3
  $ dumptags 2
  rev 2: .hgtags:
  bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
  $ dumptags 3
  rev 3: .hgtags:
  bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
  bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
  78391a272241d70354aa14c874552cad6b51bb42 bar
  $ dumptags 4
  rev 4: .hgtags:
  bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar

Dump cache:

  $ cat .hg/cache/tags2-visible
  4 0c192d7d5e6b78a714de54a2e9627952a877e25a
  bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
  bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
  78391a272241d70354aa14c874552cad6b51bb42 bar

  $ f --size --hexdump .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=120
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0030: 7a 94 12 77 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |z..w.....1....B(|
  0040: 78 ee 5a 2d ad bc 94 3d 6f a4 50 21 7d 3b 71 8c |x.Z-...=o.P!};q.|
  0050: 96 4e f3 7b 89 e5 50 eb da fd 57 89 e7 6c e1 b0 |.N.{..P...W..l..|
  0060: 0c 19 2d 7d 0c 04 f2 a8 af 31 de 17 fa b7 42 28 |..-}.....1....B(|
  0070: 78 ee 5a 2d ad bc 94 3d                         |x.Z-...=|

Corrupt the .hgtags fnodes cache
Extra junk data at the end should get overwritten on next cache update

  $ echo extra >> .hg/cache/hgtagsfnodes1
  $ echo dummy1 > foo
  $ hg commit -m throwaway1

  $ hg tags
  tip                                5:8dbfe60eff30
  bar                                1:78391a272241

  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags
  1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing 24 bytes to cache/hgtagsfnodes1
  1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> 2/3 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> tags exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @8dbfe60eff306a54259cfe007db9e330e7ecf866 (5000)> blackbox -l 6

#if unix-permissions no-root
Errors writing to .hgtags fnodes cache are silently ignored

  $ echo dummy2 > foo
  $ hg commit -m throwaway2

  $ chmod a-w .hg/cache/hgtagsfnodes1
  $ rm -f .hg/cache/tags2-visible

  $ hg tags
  tip                                6:b968051b5cf3
  bar                                1:78391a272241

  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> couldn't write cache/hgtagsfnodes1: [Errno 13] Permission denied: '$TESTTMP/t2/.hg/cache/hgtagsfnodes1'
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> 2/3 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> blackbox -l 6

  $ chmod a+w .hg/cache/hgtagsfnodes1

  $ rm -f .hg/cache/tags2-visible
  $ hg tags
  tip                                6:b968051b5cf3
  bar                                1:78391a272241

  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> writing 24 bytes to cache/hgtagsfnodes1
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> 2/3 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> tags exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @b968051b5cf3f624b771779c6d5f84f1d4c3fb5d (5000)> blackbox -l 6

  $ f --size .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=168

  $ hg -q --config extensions.strip= strip -r 6 --no-backup
#endif

Stripping doesn't truncate the tags cache until new data is available

  $ rm -f .hg/cache/hgtagsfnodes1 .hg/cache/tags2-visible
  $ hg tags
  tip                                5:8dbfe60eff30
  bar                                1:78391a272241

  $ f --size .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=144

  $ hg -q --config extensions.strip= strip -r 5 --no-backup
  $ hg tags
  tip                                4:0c192d7d5e6b
  bar                                1:78391a272241

  $ hg blackbox -l 5
  1970/01/01 00:00:00 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> writing 24 bytes to cache/hgtagsfnodes1
  1970/01/01 00:00:00 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> 2/3 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> tags exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0c192d7d5e6b78a714de54a2e9627952a877e25a (5000)> blackbox -l 5

  $ f --size .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=120

  $ echo dummy > foo
  $ hg commit -m throwaway3

  $ hg tags
  tip                                5:035f65efb448
  bar                                1:78391a272241

  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> tags
  1970/01/01 00:00:00 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> writing 24 bytes to cache/hgtagsfnodes1
  1970/01/01 00:00:00 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> 2/3 cache hits/lookups in * seconds (glob)
  1970/01/01 00:00:00 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> writing .hg/cache/tags2-visible with 1 tags
  1970/01/01 00:00:00 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> tags exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @035f65efb448350f4772141702a81ab1df48c465 (5000)> blackbox -l 6
  $ f --size .hg/cache/hgtagsfnodes1
  .hg/cache/hgtagsfnodes1: size=144

  $ hg -q --config extensions.strip= strip -r 5 --no-backup

Test tag removal:

  $ hg tag --remove bar     # rev 5
  $ hg tip -vp
  changeset:   5:5f6e8655b1c7
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       .hgtags
  description:
  Removed tag bar
  
  
  diff -r 0c192d7d5e6b -r 5f6e8655b1c7 .hgtags
  --- a/.hgtags	Thu Jan 01 00:00:00 1970 +0000
  +++ b/.hgtags	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,3 @@
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
  +78391a272241d70354aa14c874552cad6b51bb42 bar
  +0000000000000000000000000000000000000000 bar
  
  $ hg tags
  tip                                5:5f6e8655b1c7
  $ hg tags                 # again, try to expose cache bugs
  tip                                5:5f6e8655b1c7

Remove nonexistent tag:

  $ hg tag --remove foobar
  abort: tag 'foobar' does not exist
  [255]
  $ hg tip
  changeset:   5:5f6e8655b1c7
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Removed tag bar
  

Undo a tag with rollback:

  $ hg rollback             # destroy rev 5 (restore bar)
  repository tip rolled back to revision 4 (undo commit)
  working directory now based on revision 4
  $ hg tags
  tip                                4:0c192d7d5e6b
  bar                                1:78391a272241
  $ hg tags
  tip                                4:0c192d7d5e6b
  bar                                1:78391a272241

Test tag rank:

  $ cd ..
  $ hg init t3
  $ cd t3
  $ echo foo > foo
  $ hg add foo
  $ hg ci -m 'add foo'       # rev 0
  $ hg tag -f bar            # rev 1 bar -> 0
  $ hg tag -f bar            # rev 2 bar -> 1
  $ hg tag -fr 0 bar         # rev 3 bar -> 0
  $ hg tag -fr 1 bar         # rev 4 bar -> 1
  $ hg tag -fr 0 bar         # rev 5 bar -> 0
  $ hg tags
  tip                                5:85f05169d91d
  bar                                0:bbd179dfa0a7
  $ hg co 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo barbar > foo
  $ hg ci -m 'change foo'    # rev 6
  created new head
  $ hg tags
  tip                                6:735c3ca72986
  bar                                0:bbd179dfa0a7

Don't allow moving tag without -f:

  $ hg tag -r 3 bar
  abort: tag 'bar' already exists (use -f to force)
  [255]
  $ hg tags
  tip                                6:735c3ca72986
  bar                                0:bbd179dfa0a7

Strip 1: expose an old head:

  $ hg --config extensions.mq= strip 5
  saved backup bundle to $TESTTMP/t3/.hg/strip-backup/*-backup.hg (glob)
  $ hg tags                  # partly stale cache
  tip                                5:735c3ca72986
  bar                                1:78391a272241
  $ hg tags                  # up-to-date cache
  tip                                5:735c3ca72986
  bar                                1:78391a272241

Strip 2: destroy whole branch, no old head exposed

  $ hg --config extensions.mq= strip 4
  saved backup bundle to $TESTTMP/t3/.hg/strip-backup/*-backup.hg (glob)
  $ hg tags                  # partly stale
  tip                                4:735c3ca72986
  bar                                0:bbd179dfa0a7
  $ rm -f .hg/cache/tags2-visible
  $ hg tags                  # cold cache
  tip                                4:735c3ca72986
  bar                                0:bbd179dfa0a7

Test tag rank with 3 heads:

  $ cd ..
  $ hg init t4
  $ cd t4
  $ echo foo > foo
  $ hg add
  adding foo
  $ hg ci -m 'add foo'                 # rev 0
  $ hg tag bar                         # rev 1 bar -> 0
  $ hg tag -f bar                      # rev 2 bar -> 1
  $ hg up -qC 0
  $ hg tag -fr 2 bar                   # rev 3 bar -> 2
  $ hg tags
  tip                                3:197c21bbbf2c
  bar                                2:6fa450212aeb
  $ hg up -qC 0
  $ hg tag -m 'retag rev 0' -fr 0 bar  # rev 4 bar -> 0, but bar stays at 2

Bar should still point to rev 2:

  $ hg tags
  tip                                4:3b4b14ed0202
  bar                                2:6fa450212aeb

Test that removing global/local tags does not get confused when trying
to remove a tag of type X which actually only exists as a type Y:

  $ cd ..
  $ hg init t5
  $ cd t5
  $ echo foo > foo
  $ hg add
  adding foo
  $ hg ci -m 'add foo'                 # rev 0

  $ hg tag -r 0 -l localtag
  $ hg tag --remove localtag
  abort: tag 'localtag' is not a global tag
  [255]
  $ 
  $ hg tag -r 0 globaltag
  $ hg tag --remove -l globaltag
  abort: tag 'globaltag' is not a local tag
  [255]
  $ hg tags -v
  tip                                1:a0b6fe111088
  localtag                           0:bbd179dfa0a7 local
  globaltag                          0:bbd179dfa0a7

Test for issue3911

  $ hg tag -r 0 -l localtag2
  $ hg tag -l --remove localtag2
  $ hg tags -v
  tip                                1:a0b6fe111088
  localtag                           0:bbd179dfa0a7 local
  globaltag                          0:bbd179dfa0a7

  $ hg tag -r 1 -f localtag
  $ hg tags -v
  tip                                2:5c70a037bb37
  localtag                           1:a0b6fe111088
  globaltag                          0:bbd179dfa0a7

  $ hg tags -v
  tip                                2:5c70a037bb37
  localtag                           1:a0b6fe111088
  globaltag                          0:bbd179dfa0a7

  $ hg tag -r 1 localtag2
  $ hg tags -v
  tip                                3:bbfb8cd42be2
  localtag2                          1:a0b6fe111088
  localtag                           1:a0b6fe111088
  globaltag                          0:bbd179dfa0a7

  $ hg tags -v
  tip                                3:bbfb8cd42be2
  localtag2                          1:a0b6fe111088
  localtag                           1:a0b6fe111088
  globaltag                          0:bbd179dfa0a7

  $ cd ..

Create a repository with tags data to test .hgtags fnodes transfer

  $ hg init tagsserver
  $ cd tagsserver
  $ touch foo
  $ hg -q commit -A -m initial
  $ hg tag -m 'tag 0.1' 0.1
  $ echo second > foo
  $ hg commit -m second
  $ hg tag -m 'tag 0.2' 0.2
  $ hg tags
  tip                                3:40f0358cb314
  0.2                                2:f63cc8fe54e4
  0.1                                0:96ee1d7354c4
  $ cd ..

Cloning should pull down hgtags fnodes mappings and write the cache file

  $ hg clone --pull tagsserver tagsclient
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

Missing tags2* files means the cache wasn't written through the normal mechanism.

  $ ls tagsclient/.hg/cache
  branch2-served
  hgtagsfnodes1
  rbc-names-v1
  rbc-revs-v1

Cache should contain the head only, even though other nodes have tags data

  $ f --size --hexdump tagsclient/.hg/cache/hgtagsfnodes1
  tagsclient/.hg/cache/hgtagsfnodes1: size=96
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0040: ff ff ff ff ff ff ff ff 40 f0 35 8c 19 e0 a7 d3 |........@.5.....|
  0050: 8a 5c 6a 82 4d cf fb a5 87 d0 2f a3 1e 4f 2f 8a |.\j.M...../..O/.|

Running hg tags should produce tags2* file and not change cache

  $ hg -R tagsclient tags
  tip                                3:40f0358cb314
  0.2                                2:f63cc8fe54e4
  0.1                                0:96ee1d7354c4

  $ ls tagsclient/.hg/cache
  branch2-served
  hgtagsfnodes1
  rbc-names-v1
  rbc-revs-v1
  tags2-visible

  $ f --size --hexdump tagsclient/.hg/cache/hgtagsfnodes1
  tagsclient/.hg/cache/hgtagsfnodes1: size=96
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0040: ff ff ff ff ff ff ff ff 40 f0 35 8c 19 e0 a7 d3 |........@.5.....|
  0050: 8a 5c 6a 82 4d cf fb a5 87 d0 2f a3 1e 4f 2f 8a |.\j.M...../..O/.|