tests/test-persistent-nodemap.t

copies: iterate over children directly (instead of parents)

Before this change we would gather all parent → child edges and iterate on
all parent, gathering copy information for children and aggregating them from
there.

They are not strict requirement for edges to be processed in that specific
order. We could also simply iterate over all "children" revision and aggregate
data from both parents at the same time. This patch does that.

It make various things simpler:

 * since both parents are processed at the same time, we no longer need to
   cache data for merge (see next changeset for details),

 * we no longer need nested loop to process data,

 * we no longer need to store partial merge data for a rev from distinct loop
   interaction to another when processing merges,

 * we no longer need to build a full parent -> children mapping (we only rely on
   a simpler "parent -> number of children" map (for memory efficiency),

 * the data access pattern is now simpler (from lower revisions to higher
   revisions) and entirely predicable. That predictability open the way to
   prefetching and parallel processing.

So that new iterations order requires simpler code and open the way to
interesting optimisation.

The effect on performance is quite good. In the worse case, we don't see any
significant negative impact. And in the best case, the reduction of roundtrip
to Python provide us with a significant speed. Some example below:

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  old time    new time      Difference    Factor    time per rev
---------------------------------------------------------------------------------------------------------------------------------------------------------------
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c :  34414 revs,   0.962867 s,   0.502584 s,  -0.460283 s, × 0.5220,    14 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :   8598 revs,   0.110717 s,   0.076323 s,  -0.034394 s, × 0.6894,     8 µs/rev



# full comparison between the previous changeset and this one

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  old time    new time      Difference    Factor    time per rev
---------------------------------------------------------------------------------------------------------------------------------------------------------------
mercurial       x_revs_x_added_0_copies               ad6b123de1c7 39cfcef4f463 :      1 revs,   0.000048 s,   0.000041 s,  -0.000007 s, × 0.8542,    41 µs/rev
mercurial       x_revs_x_added_x_copies               2b1c78674230 0c1d10351869 :      6 revs,   0.000153 s,   0.000102 s,  -0.000051 s, × 0.6667,    17 µs/rev
mercurial       x000_revs_x000_added_x_copies         81f8ff2a9bf2 dd3267698d84 :   1032 revs,   0.004209 s,   0.004254 s,  +0.000045 s, × 1.0107,     4 µs/rev
pypy            x_revs_x_added_0_copies               aed021ee8ae8 099ed31b181b :      9 revs,   0.000203 s,   0.000282 s,  +0.000079 s, × 1.3892,    31 µs/rev
pypy            x_revs_x000_added_0_copies            4aa4e1f8e19a 359343b9ac0e :      1 revs,   0.000059 s,   0.000048 s,  -0.000011 s, × 0.8136,    48 µs/rev
pypy            x_revs_x_added_x_copies               ac52eb7bbbb0 72e022663155 :      7 revs,   0.000194 s,   0.000211 s,  +0.000017 s, × 1.0876,    30 µs/rev
pypy            x_revs_x00_added_x_copies             c3b14617fbd7 ace7255d9a26 :      1 revs,   0.000380 s,   0.000375 s,  -0.000005 s, × 0.9868,   375 µs/rev
pypy            x_revs_x000_added_x000_copies         df6f7a526b60 a83dc6a2d56f :      6 revs,   0.010588 s,   0.010574 s,  -0.000014 s, × 0.9987,  1762 µs/rev
pypy            x000_revs_xx00_added_0_copies         89a76aede314 2f22446ff07e :   4785 revs,   0.048961 s,   0.049974 s,  +0.001013 s, × 1.0207,    10 µs/rev
pypy            x000_revs_x000_added_x_copies         8a3b5bfd266e 2c68e87c3efe :   6780 revs,   0.083612 s,   0.084300 s,  +0.000688 s, × 1.0082,    12 µs/rev
pypy            x000_revs_x000_added_x000_copies      89a76aede314 7b3dda341c84 :   5441 revs,   0.058579 s,   0.060128 s,  +0.001549 s, × 1.0264,    11 µs/rev
pypy            x0000_revs_x_added_0_copies           d1defd0dc478 c9cb1334cc78 :  43645 revs,   0.736783 s,   0.686542 s,  -0.050241 s, × 0.9318,    15 µs/rev
pypy            x0000_revs_xx000_added_0_copies       bf2c629d0071 4ffed77c095c :      2 revs,   0.022050 s,   0.009277 s,  -0.012773 s, × 0.4207,  4638 µs/rev
pypy            x0000_revs_xx000_added_x000_copies    08ea3258278e d9fa043f30c0 :  11316 revs,   0.120800 s,   0.114733 s,  -0.006067 s, × 0.9498,    10 µs/rev
netbeans        x_revs_x_added_0_copies               fb0955ffcbcd a01e9239f9e7 :      2 revs,   0.000140 s,   0.000081 s,  -0.000059 s, × 0.5786,    40 µs/rev
netbeans        x_revs_x000_added_0_copies            6f360122949f 20eb231cc7d0 :      2 revs,   0.000114 s,   0.000107 s,  -0.000007 s, × 0.9386,    53 µs/rev
netbeans        x_revs_x_added_x_copies               1ada3faf6fb6 5a39d12eecf4 :      3 revs,   0.000224 s,   0.000173 s,  -0.000051 s, × 0.7723,    57 µs/rev
netbeans        x_revs_x00_added_x_copies             35be93ba1e2c 9eec5e90c05f :      9 revs,   0.000723 s,   0.000698 s,  -0.000025 s, × 0.9654,    77 µs/rev
netbeans        x000_revs_xx00_added_0_copies         eac3045b4fdd 51d4ae7f1290 :   1421 revs,   0.009665 s,   0.009248 s,  -0.000417 s, × 0.9569,     6 µs/rev
netbeans        x000_revs_x000_added_x_copies         e2063d266acd 6081d72689dc :   1533 revs,   0.014820 s,   0.015446 s,  +0.000626 s, × 1.0422,    10 µs/rev
netbeans        x000_revs_x000_added_x000_copies      ff453e9fee32 411350406ec2 :   5750 revs,   0.076049 s,   0.074373 s,  -0.001676 s, × 0.9780,    12 µs/rev
netbeans        x0000_revs_xx000_added_x000_copies    588c2d1ced70 1aad62e59ddd :  66949 revs,   0.683603 s,   0.639870 s,  -0.043733 s, × 0.9360,     9 µs/rev
mozilla-central x_revs_x_added_0_copies               3697f962bb7b 7015fcdd43a2 :      2 revs,   0.000161 s,   0.000088 s,  -0.000073 s, × 0.5466,    44 µs/rev
mozilla-central x_revs_x000_added_0_copies            dd390860c6c9 40d0c5bed75d :      8 revs,   0.000234 s,   0.000199 s,  -0.000035 s, × 0.8504,    24 µs/rev
mozilla-central x_revs_x_added_x_copies               8d198483ae3b 14207ffc2b2f :      9 revs,   0.000247 s,   0.000171 s,  -0.000076 s, × 0.6923,    19 µs/rev
mozilla-central x_revs_x00_added_x_copies             98cbc58cc6bc 446a150332c3 :      7 revs,   0.000630 s,   0.000592 s,  -0.000038 s, × 0.9397,    84 µs/rev
mozilla-central x_revs_x000_added_x000_copies         3c684b4b8f68 0a5e72d1b479 :      3 revs,   0.003286 s,   0.003151 s,  -0.000135 s, × 0.9589,  1050 µs/rev
mozilla-central x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.062441 s,   0.061612 s,  -0.000829 s, × 0.9867, 10268 µs/rev
mozilla-central x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.005423 s,   0.005381 s,  -0.000042 s, × 0.9923,     3 µs/rev
mozilla-central x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :     41 revs,   0.005919 s,   0.003742 s,  -0.002177 s, × 0.6322,    91 µs/rev
mozilla-central x000_revs_x000_added_x000_copies      7c97034feb78 4407bd0c6330 :   7839 revs,   0.062597 s,   0.061983 s,  -0.000614 s, × 0.9902,     7 µs/rev
mozilla-central x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :    615 revs,   0.043551 s,   0.019861 s,  -0.023690 s, × 0.4560,    32 µs/rev
mozilla-central x0000_revs_xx000_added_x000_copies    f78c615a656c 96a38b690156 :  30263 revs,   0.192475 s,   0.188101 s,  -0.004374 s, × 0.9773,     6 µs/rev
mozilla-central x00000_revs_x0000_added_x0000_copies  6832ae71433c 4c222a1d9a00 : 153721 revs,   1.955575 s,   1.806696 s,  -0.148879 s, × 0.9239,    11 µs/rev
mozilla-central x00000_revs_x00000_added_x000_copies  76caed42cf7c 1daa622bbe42 : 204976 revs,   2.886501 s,   2.682987 s,  -0.203514 s, × 0.9295,    13 µs/rev
mozilla-try     x_revs_x_added_0_copies               aaf6dde0deb8 9790f499805a :      2 revs,   0.001181 s,   0.000852 s,  -0.000329 s, × 0.7214,   426 µs/rev
mozilla-try     x_revs_x000_added_0_copies            d8d0222927b4 5bb8ce8c7450 :      2 revs,   0.001189 s,   0.000859 s,  -0.000330 s, × 0.7225,   429 µs/rev
mozilla-try     x_revs_x_added_x_copies               092fcca11bdb 936255a0384a :      4 revs,   0.000563 s,   0.000150 s,  -0.000413 s, × 0.2664,    37 µs/rev
mozilla-try     x_revs_x00_added_x_copies             b53d2fadbdb5 017afae788ec :      2 revs,   0.001548 s,   0.001158 s,  -0.000390 s, × 0.7481,   579 µs/rev
mozilla-try     x_revs_x000_added_x000_copies         20408ad61ce5 6f0ee96e21ad :      1 revs,   0.027782 s,   0.027240 s,  -0.000542 s, × 0.9805, 27240 µs/rev
mozilla-try     x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.062781 s,   0.062824 s,  +0.000043 s, × 1.0007, 10470 µs/rev
mozilla-try     x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.005778 s,   0.005463 s,  -0.000315 s, × 0.9455,     3 µs/rev
mozilla-try     x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :     41 revs,   0.006192 s,   0.004238 s,  -0.001954 s, × 0.6844,   103 µs/rev
mozilla-try     x000_revs_x000_added_x000_copies      1346fd0130e4 4c65cbdabc1f :   6657 revs,   0.065391 s,   0.064113 s,  -0.001278 s, × 0.9805,     9 µs/rev
mozilla-try     x0000_revs_x_added_0_copies           63519bfd42ee a36a2a865d92 :  40314 revs,   0.317216 s,   0.294063 s,  -0.023153 s, × 0.9270,     7 µs/rev
mozilla-try     x0000_revs_x_added_x_copies           9fe69ff0762d bcabf2a78927 :  38690 revs,   0.303119 s,   0.281493 s,  -0.021626 s, × 0.9287,     7 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :   8598 revs,   0.110717 s,   0.076323 s,  -0.034394 s, × 0.6894,     8 µs/rev
mozilla-try     x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :    615 revs,   0.045739 s,   0.020390 s,  -0.025349 s, × 0.4458,    33 µs/rev
mozilla-try     x0000_revs_xx000_added_x000_copies    89294cd501d9 7ccb2fc7ccb5 :  97052 revs,   3.098021 s,   3.023879 s,  -0.074142 s, × 0.9761,    31 µs/rev
mozilla-try     x0000_revs_x0000_added_x0000_copies   e928c65095ed e951f4ad123a :  52031 revs,   0.771480 s,   0.735549 s,  -0.035931 s, × 0.9534,    14 µs/rev
mozilla-try     x00000_revs_x_added_0_copies          6a320851d377 1ebb79acd503 : 363753 revs,  18.813422 s,  18.568900 s,  -0.244522 s, × 0.9870,    51 µs/rev
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c :  34414 revs,   0.962867 s,   0.502584 s,  -0.460283 s, × 0.5220,    14 µs/rev
mozilla-try     x00000_revs_x_added_x_copies          5173c4b6f97c 95d83ee7242d : 362229 revs,  18.684923 s,  18.356645 s,  -0.328278 s, × 0.9824,    50 µs/rev
mozilla-try     x00000_revs_x000_added_x_copies       9126823d0e9c ca82787bb23c : 359344 revs,  18.296305 s,  18.250393 s,  -0.045912 s, × 0.9975,    50 µs/rev
mozilla-try     x00000_revs_x0000_added_x0000_copies  8d3fafa80d4b eb884023b810 : 192665 revs,   3.061887 s,   2.792459 s,  -0.269428 s, × 0.9120,    14 µs/rev
mozilla-try     x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 228985 revs, 103.869641 s, 107.697264 s,  +3.827623 s, × 1.0369,   470 µs/rev
mozilla-try     x00000_revs_x00000_added_x000_copies  9b2a99adc05e 8e29777b48e6 : 382065 revs,  64.262957 s,  63.961040 s,  -0.301917 s, × 0.9953,   167 µs/rev

Differential Revision: https://phab.mercurial-scm.org/D9422

===================================
Test the persistent on-disk nodemap
===================================

  $ cat << EOF >> $HGRCPATH
  > [format]
  > use-persistent-nodemap=yes
  > [devel]
  > persistent-nodemap=yes
  > EOF
  $ hg init test-repo
  $ cd test-repo
  $ hg debugformat
  format-variant     repo
  fncache:            yes
  dotencode:          yes
  generaldelta:       yes
  exp-sharesafe:       no
  sparserevlog:       yes
  sidedata:            no
  persistent-nodemap: yes
  copies-sdc:          no
  plain-cl-delta:     yes
  compression:        zlib
  compression-level:  default
  $ hg debugbuilddag .+5000 --new-file --config "storage.revlog.nodemap.mode=warn"
  persistent nodemap in strict mode without efficient method (no-rust no-pure !)
  persistent nodemap in strict mode without efficient method (no-rust no-pure !)
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5000
  tip-node: 6b02b8c7b96654c25e86ba69eda198d7e6ad8b3c
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
  $ f --size .hg/store/00changelog.n
  .hg/store/00changelog.n: size=70

Simple lookup works

  $ ANYNODE=`hg log --template '{node|short}\n' --rev tip`
  $ hg log -r "$ANYNODE" --template '{rev}\n'
  5000


#if rust

  $ f --sha256 .hg/store/00changelog-*.nd
  .hg/store/00changelog-????????????????.nd: sha256=2e029d3200bd1a986b32784fc2ef1a3bd60dc331f025718bcf5ff44d93f026fd (glob)

  $ f --sha256 .hg/store/00manifest-*.nd
  .hg/store/00manifest-????????????????.nd: sha256=97117b1c064ea2f86664a124589e47db0e254e8d34739b5c5cc5bf31c9da2b51 (glob)
  $ hg debugnodemap --dump-new | f --sha256 --size
  size=121088, sha256=2e029d3200bd1a986b32784fc2ef1a3bd60dc331f025718bcf5ff44d93f026fd
  $ hg debugnodemap --dump-disk | f --sha256 --bytes=256 --hexdump --size
  size=121088, sha256=2e029d3200bd1a986b32784fc2ef1a3bd60dc331f025718bcf5ff44d93f026fd
  0000: 00 00 00 91 00 00 00 20 00 00 00 bb 00 00 00 e7 |....... ........|
  0010: 00 00 00 66 00 00 00 a1 00 00 01 13 00 00 01 22 |...f..........."|
  0020: 00 00 00 23 00 00 00 fc 00 00 00 ba 00 00 00 5e |...#...........^|
  0030: 00 00 00 df 00 00 01 4e 00 00 01 65 00 00 00 ab |.......N...e....|
  0040: 00 00 00 a9 00 00 00 95 00 00 00 73 00 00 00 38 |...........s...8|
  0050: 00 00 00 cc 00 00 00 92 00 00 00 90 00 00 00 69 |...............i|
  0060: 00 00 00 ec 00 00 00 8d 00 00 01 4f 00 00 00 12 |...........O....|
  0070: 00 00 02 0c 00 00 00 77 00 00 00 9c 00 00 00 8f |.......w........|
  0080: 00 00 00 d5 00 00 00 6b 00 00 00 48 00 00 00 b3 |.......k...H....|
  0090: 00 00 00 e5 00 00 00 b5 00 00 00 8e 00 00 00 ad |................|
  00a0: 00 00 00 7b 00 00 00 7c 00 00 00 0b 00 00 00 2b |...{...|.......+|
  00b0: 00 00 00 c6 00 00 00 1e 00 00 01 08 00 00 00 11 |................|
  00c0: 00 00 01 30 00 00 00 26 00 00 01 9c 00 00 00 35 |...0...&.......5|
  00d0: 00 00 00 b8 00 00 01 31 00 00 00 2c 00 00 00 55 |.......1...,...U|
  00e0: 00 00 00 8a 00 00 00 9a 00 00 00 0c 00 00 01 1e |................|
  00f0: 00 00 00 a4 00 00 00 83 00 00 00 c9 00 00 00 8c |................|


#else

  $ f --sha256 .hg/store/00changelog-*.nd
  .hg/store/00changelog-????????????????.nd: sha256=f544f5462ff46097432caf6d764091f6d8c46d6121be315ead8576d548c9dd79 (glob)
  $ hg debugnodemap --dump-new | f --sha256 --size
  size=121088, sha256=f544f5462ff46097432caf6d764091f6d8c46d6121be315ead8576d548c9dd79
  $ hg debugnodemap --dump-disk | f --sha256 --bytes=256 --hexdump --size
  size=121088, sha256=f544f5462ff46097432caf6d764091f6d8c46d6121be315ead8576d548c9dd79
  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 f5 06 ff ff ff ff ff ff f3 e7 |................|
  0030: ff ff ef ca ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0040: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0050: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ed 08 |................|
  0060: ff ff ed 66 ff ff ff ff ff ff ff ff ff ff ff ff |...f............|
  0070: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0090: ff ff ff ff ff ff ff ff ff ff ff ff ff ff f6 ed |................|
  00a0: ff ff ff ff ff ff fe 61 ff ff ff ff ff ff ff ff |.......a........|
  00b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  00c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  00d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  00e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff f1 02 |................|
  00f0: ff ff ff ff ff ff ed 1b ff ff ff ff ff ff ff ff |................|

#endif

  $ hg debugnodemap --check
  revision in index:   5001
  revision in nodemap: 5001

add a new commit

  $ hg up
  5001 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo foo > foo
  $ hg add foo

#if no-pure no-rust

  $ hg ci -m 'foo' --config "storage.revlog.nodemap.mode=strict"
  transaction abort!
  rollback completed
  abort: persistent nodemap in strict mode without efficient method
  [255]

#endif

  $ hg ci -m 'foo'

#if no-pure no-rust
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5001
  tip-node: 16395c3cf7e231394735e6b1717823ada303fb0c
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
#else
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5001
  tip-node: 16395c3cf7e231394735e6b1717823ada303fb0c
  data-length: 121344
  data-unused: 256
  data-unused: 0.211%
#endif

  $ f --size .hg/store/00changelog.n
  .hg/store/00changelog.n: size=70

(The pure code use the debug code that perform incremental update, the C code reencode from scratch)

#if pure
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=121344, sha256=cce54c5da5bde3ad72a4938673ed4064c86231b9c64376b082b163fdb20f8f66 (glob)
#endif

#if rust
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=121344, sha256=952b042fcf614ceb37b542b1b723e04f18f83efe99bee4e0f5ccd232ef470e58 (glob)
#endif

#if no-pure no-rust
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=121088, sha256=df7c06a035b96cb28c7287d349d603baef43240be7736fe34eea419a49702e17 (glob)
#endif

  $ hg debugnodemap --check
  revision in index:   5002
  revision in nodemap: 5002

Test code path without mmap
---------------------------

  $ echo bar > bar
  $ hg add bar
  $ hg ci -m 'bar' --config storage.revlog.nodemap.mmap=no

  $ hg debugnodemap --check --config storage.revlog.nodemap.mmap=yes
  revision in index:   5003
  revision in nodemap: 5003
  $ hg debugnodemap --check --config storage.revlog.nodemap.mmap=no
  revision in index:   5003
  revision in nodemap: 5003


#if pure
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121600
  data-unused: 512
  data-unused: 0.421%
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=121600, sha256=def52503d049ccb823974af313a98a935319ba61f40f3aa06a8be4d35c215054 (glob)
#endif
#if rust
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121600
  data-unused: 512
  data-unused: 0.421%
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=121600, sha256=dacf5b5f1d4585fee7527d0e67cad5b1ba0930e6a0928f650f779aefb04ce3fb (glob)
#endif
#if no-pure no-rust
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=121088, sha256=59fcede3e3cc587755916ceed29e3c33748cd1aa7d2f91828ac83e7979d935e8 (glob)
#endif

Test force warming the cache

  $ rm .hg/store/00changelog.n
  $ hg debugnodemap --metadata
  $ hg debugupdatecache
#if pure
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
#else
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
#endif

Check out of sync nodemap
=========================

First copy old data on the side.

  $ mkdir ../tmp-copies
  $ cp .hg/store/00changelog-????????????????.nd .hg/store/00changelog.n ../tmp-copies

Nodemap lagging behind
----------------------

make a new commit

  $ echo bar2 > bar
  $ hg ci -m 'bar2'
  $ NODE=`hg log -r tip -T '{node}\n'`
  $ hg log -r "$NODE" -T '{rev}\n'
  5003

If the nodemap is lagging behind, it can catch up fine

  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5003
  tip-node: c9329770f979ade2d16912267c38ba5f82fd37b3
  data-length: 121344 (pure !)
  data-length: 121344 (rust !)
  data-length: 121152 (no-rust no-pure !)
  data-unused: 192 (pure !)
  data-unused: 192 (rust !)
  data-unused: 0 (no-rust no-pure !)
  data-unused: 0.158% (pure !)
  data-unused: 0.158% (rust !)
  data-unused: 0.000% (no-rust no-pure !)
  $ cp -f ../tmp-copies/* .hg/store/
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
  $ hg log -r "$NODE" -T '{rev}\n'
  5003

changelog altered
-----------------

If the nodemap is not gated behind a requirements, an unaware client can alter
the repository so the revlog used to generate the nodemap is not longer
compatible with the persistent nodemap. We need to detect that.

  $ hg up "$NODE~5"
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ echo bar > babar
  $ hg add babar
  $ hg ci -m 'babar'
  created new head
  $ OTHERNODE=`hg log -r tip -T '{node}\n'`
  $ hg log -r "$OTHERNODE" -T '{rev}\n'
  5004

  $ hg --config extensions.strip= strip --rev "$NODE~1" --no-backup

the nodemap should detect the changelog have been tampered with and recover.

  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: b355ef8adce0949b8bdf6afc72ca853740d65944
  data-length: 121536 (pure !)
  data-length: 121088 (rust !)
  data-length: 121088 (no-pure no-rust !)
  data-unused: 448 (pure !)
  data-unused: 0 (rust !)
  data-unused: 0 (no-pure no-rust !)
  data-unused: 0.000% (rust !)
  data-unused: 0.369% (pure !)
  data-unused: 0.000% (no-pure no-rust !)

  $ cp -f ../tmp-copies/* .hg/store/
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5002
  tip-node: 880b18d239dfa9f632413a2071bfdbcc4806a4fd
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
  $ hg log -r "$OTHERNODE" -T '{rev}\n'
  5002

Check transaction related property
==================================

An up to date nodemap should be available to shell hooks,

  $ echo dsljfl > a
  $ hg add a
  $ hg ci -m a
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5003
  tip-node: a52c5079765b5865d97b993b303a18740113bbb2
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%
  $ echo babar2 > babar
  $ hg ci -m 'babar2' --config "hooks.pretxnclose.nodemap-test=hg debugnodemap --metadata"
  uid: ???????????????? (glob)
  tip-rev: 5004
  tip-node: 2f5fb1c06a16834c5679d672e90da7c5f3b1a984
  data-length: 121280 (pure !)
  data-length: 121280 (rust !)
  data-length: 121088 (no-pure no-rust !)
  data-unused: 192 (pure !)
  data-unused: 192 (rust !)
  data-unused: 0 (no-pure no-rust !)
  data-unused: 0.158% (pure !)
  data-unused: 0.158% (rust !)
  data-unused: 0.000% (no-pure no-rust !)
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5004
  tip-node: 2f5fb1c06a16834c5679d672e90da7c5f3b1a984
  data-length: 121280 (pure !)
  data-length: 121280 (rust !)
  data-length: 121088 (no-pure no-rust !)
  data-unused: 192 (pure !)
  data-unused: 192 (rust !)
  data-unused: 0 (no-pure no-rust !)
  data-unused: 0.158% (pure !)
  data-unused: 0.158% (rust !)
  data-unused: 0.000% (no-pure no-rust !)

Another process does not see the pending nodemap content during run.

  $ PATH=$RUNTESTDIR/testlib/:$PATH
  $ echo qpoasp > a
  $ hg ci -m a2 \
  > --config "hooks.pretxnclose=wait-on-file 20 sync-repo-read sync-txn-pending" \
  > --config "hooks.txnclose=touch sync-txn-close" > output.txt 2>&1 &

(read the repository while the commit transaction is pending)

  $ wait-on-file 20 sync-txn-pending && \
  > hg debugnodemap --metadata && \
  > wait-on-file 20 sync-txn-close sync-repo-read
  uid: ???????????????? (glob)
  tip-rev: 5004
  tip-node: 2f5fb1c06a16834c5679d672e90da7c5f3b1a984
  data-length: 121280 (pure !)
  data-length: 121280 (rust !)
  data-length: 121088 (no-pure no-rust !)
  data-unused: 192 (pure !)
  data-unused: 192 (rust !)
  data-unused: 0 (no-pure no-rust !)
  data-unused: 0.158% (pure !)
  data-unused: 0.158% (rust !)
  data-unused: 0.000% (no-pure no-rust !)
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5005
  tip-node: 90d5d3ba2fc47db50f712570487cb261a68c8ffe
  data-length: 121536 (pure !)
  data-length: 121536 (rust !)
  data-length: 121088 (no-pure no-rust !)
  data-unused: 448 (pure !)
  data-unused: 448 (rust !)
  data-unused: 0 (no-pure no-rust !)
  data-unused: 0.369% (pure !)
  data-unused: 0.369% (rust !)
  data-unused: 0.000% (no-pure no-rust !)

  $ cat output.txt

Check that a failing transaction will properly revert the data

  $ echo plakfe > a
  $ f --size --sha256 .hg/store/00changelog-*.nd
  .hg/store/00changelog-????????????????.nd: size=121536, sha256=bb414468d225cf52d69132e1237afba34d4346ee2eb81b505027e6197b107f03 (glob) (pure !)
  .hg/store/00changelog-????????????????.nd: size=121536, sha256=909ac727bc4d1c0fda5f7bff3c620c98bd4a2967c143405a1503439e33b377da (glob) (rust !)
  .hg/store/00changelog-????????????????.nd: size=121088, sha256=342d36d30d86dde67d3cb6c002606c4a75bcad665595d941493845066d9c8ee0 (glob) (no-pure no-rust !)
  $ hg ci -m a3 --config "extensions.abort=$RUNTESTDIR/testlib/crash_transaction_late.py"
  transaction abort!
  rollback completed
  abort: This is a late abort
  [255]
  $ hg debugnodemap --metadata
  uid: ???????????????? (glob)
  tip-rev: 5005
  tip-node: 90d5d3ba2fc47db50f712570487cb261a68c8ffe
  data-length: 121536 (pure !)
  data-length: 121536 (rust !)
  data-length: 121088 (no-pure no-rust !)
  data-unused: 448 (pure !)
  data-unused: 448 (rust !)
  data-unused: 0 (no-pure no-rust !)
  data-unused: 0.369% (pure !)
  data-unused: 0.369% (rust !)
  data-unused: 0.000% (no-pure no-rust !)
  $ f --size --sha256 .hg/store/00changelog-*.nd
  .hg/store/00changelog-????????????????.nd: size=121536, sha256=bb414468d225cf52d69132e1237afba34d4346ee2eb81b505027e6197b107f03 (glob) (pure !)
  .hg/store/00changelog-????????????????.nd: size=121536, sha256=909ac727bc4d1c0fda5f7bff3c620c98bd4a2967c143405a1503439e33b377da (glob) (rust !)
  .hg/store/00changelog-????????????????.nd: size=121088, sha256=342d36d30d86dde67d3cb6c002606c4a75bcad665595d941493845066d9c8ee0 (glob) (no-pure no-rust !)

Check that removing content does not confuse the nodemap
--------------------------------------------------------

removing data with rollback

  $ echo aso > a
  $ hg ci -m a4
  $ hg rollback
  repository tip rolled back to revision 5005 (undo commit)
  working directory now based on revision 5005
  $ hg id -r .
  90d5d3ba2fc4 tip

roming data with strip

  $ echo aso > a
  $ hg ci -m a4
  $ hg --config extensions.strip= strip -r . --no-backup
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -r . --traceback
  90d5d3ba2fc4 tip

Test upgrade / downgrade
========================

downgrading

  $ cat << EOF >> .hg/hgrc
  > [format]
  > use-persistent-nodemap=no
  > EOF
  $ hg debugformat -v
  format-variant     repo config default
  fncache:            yes    yes     yes
  dotencode:          yes    yes     yes
  generaldelta:       yes    yes     yes
  exp-sharesafe:       no     no      no
  sparserevlog:       yes    yes     yes
  sidedata:            no     no      no
  persistent-nodemap: yes     no      no
  copies-sdc:          no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib
  compression-level:  default default default
  $ hg debugupgraderepo --run --no-backup --quiet
  upgrade will perform the following actions:
  
  requirements
     preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store
     removed: persistent-nodemap
  
  processed revlogs:
    - all-filelogs
    - changelog
    - manifest
  
  $ ls -1 .hg/store/ | egrep '00(changelog|manifest)(\.n|-.*\.nd)'
  [1]
  $ hg debugnodemap --metadata


upgrading

  $ cat << EOF >> .hg/hgrc
  > [format]
  > use-persistent-nodemap=yes
  > EOF
  $ hg debugformat -v
  format-variant     repo config default
  fncache:            yes    yes     yes
  dotencode:          yes    yes     yes
  generaldelta:       yes    yes     yes
  exp-sharesafe:       no     no      no
  sparserevlog:       yes    yes     yes
  sidedata:            no     no      no
  persistent-nodemap:  no    yes      no
  copies-sdc:          no     no      no
  plain-cl-delta:     yes    yes     yes
  compression:        zlib   zlib    zlib
  compression-level:  default default default
  $ hg debugupgraderepo --run --no-backup --quiet
  upgrade will perform the following actions:
  
  requirements
     preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store
     added: persistent-nodemap
  
  processed revlogs:
    - all-filelogs
    - changelog
    - manifest
  
  $ ls -1 .hg/store/ | egrep '00(changelog|manifest)(\.n|-.*\.nd)'
  00changelog-*.nd (glob)
  00changelog.n
  00manifest-*.nd (glob)
  00manifest.n

  $ hg debugnodemap --metadata
  uid: * (glob)
  tip-rev: 5005
  tip-node: 90d5d3ba2fc47db50f712570487cb261a68c8ffe
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%

Running unrelated upgrade

  $ hg debugupgraderepo --run --no-backup --quiet --optimize re-delta-all
  upgrade will perform the following actions:
  
  requirements
     preserved: dotencode, fncache, generaldelta, persistent-nodemap, revlogv1, sparserevlog, store
  
  optimisations: re-delta-all
  
  processed revlogs:
    - all-filelogs
    - changelog
    - manifest
  
  $ ls -1 .hg/store/ | egrep '00(changelog|manifest)(\.n|-.*\.nd)'
  00changelog-*.nd (glob)
  00changelog.n
  00manifest-*.nd (glob)
  00manifest.n

  $ hg debugnodemap --metadata
  uid: * (glob)
  tip-rev: 5005
  tip-node: 90d5d3ba2fc47db50f712570487cb261a68c8ffe
  data-length: 121088
  data-unused: 0
  data-unused: 0.000%