tests/test-obsolete-divergent.t
author Pierre-Yves David <pierre-yves.david@octobus.net>
Mon, 14 Dec 2020 11:32:24 +0100
changeset 46149 294d5aca4ff5
parent 45194 6063c1857d0a
child 50722 7e5be4a7cda7
permissions -rw-r--r--
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 file dedicated to testing the divergent troubles from obsolete changeset.

This is the most complex troubles from far so we isolate it in a dedicated
file.

Enable obsolete

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > logtemplate = {rev}:{node|short} {desc}{if(obsfate, " [{join(obsfate, "; ")}]")}\n
  > [experimental]
  > evolution.createmarkers=True
  > [extensions]
  > drawdag=$TESTDIR/drawdag.py
  > [alias]
  > debugobsolete = debugobsolete -d '0 0'
  > [phases]
  > publish=False
  > [templates]
  > wuentryshort = '{instability}:{if(divergentnodes, " ")}{divergentnodes} {reason} {node|shortest}\n'
  > whyunstableshort = '{whyunstable % wuentryshort}'
  > wuentryshorter = '{instability}:{divergentnodes % " {node|shortest} ({phase})"} {reason} {node|shortest}\n'
  > whyunstableshorter = '{whyunstable % wuentryshorter}'
  > EOF


  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    hg ci -m "$1"
  > }
  $ getid() {
  >    hg log --hidden -r "desc('$1')" -T '{node}\n'
  > }

setup repo

  $ hg init reference
  $ cd reference
  $ mkcommit base
  $ mkcommit A_0
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A_1
  created new head
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A_2
  created new head
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ cd ..


  $ newcase() {
  >    hg clone -u 0 -q reference $1
  >    cd $1
  > }

direct divergence
-----------------

A_1 have two direct and divergent successors A_1 and A_1

  $ newcase direct
  $ hg debugobsolete `getid A_0` `getid A_1`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_0` `getid A_2`
  1 new obsolescence markers
  2 new content-divergent changesets
  $ hg log -G --hidden
  *  3:392fd25390da A_2
  |
  | *  2:82623d38b9ba A_1
  |/
  | x  1:007dc284c1f8 A_0 [rewritten as 2:82623d38b9ba; rewritten as 3:392fd25390da]
  |/
  @  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ hg log -r 'contentdivergent()'
  2:82623d38b9ba A_1
  3:392fd25390da A_2
  $ hg log -r 'unstable()'
  2:82623d38b9ba A_1
  3:392fd25390da A_2
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da

check that mercurial refuse to push

  $ hg init ../other
  $ hg push ../other
  pushing to ../other
  searching for changes
  abort: push includes content-divergent changeset: 392fd25390da!
  [255]

  $ cd ..


indirect divergence with known changeset
-------------------------------------------

  $ newcase indirect_known
  $ hg debugobsolete `getid A_0` `getid A_1`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_0` `getid A_2`
  1 new obsolescence markers
  2 new content-divergent changesets
  $ mkcommit A_3
  created new head
  $ hg debugobsolete `getid A_2` `getid A_3`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  4:01f36c5a8fda A_3
  |
  | x  3:392fd25390da A_2 [rewritten as 4:01f36c5a8fda]
  |/
  | *  2:82623d38b9ba A_1
  |/
  | x  1:007dc284c1f8 A_0 [rewritten as 2:82623d38b9ba; rewritten as 3:392fd25390da]
  |/
  o  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      01f36c5a8fda
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      01f36c5a8fda
  01f36c5a8fda
      01f36c5a8fda
  $ hg log -r 'contentdivergent()'
  2:82623d38b9ba A_1
  4:01f36c5a8fda A_3
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  82623d38b9ba
      82623d38b9ba
  01f36c5a8fda
      01f36c5a8fda
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  01f36c5a8fda
      01f36c5a8fda
  $ cd ..


indirect divergence with known changeset
-------------------------------------------

  $ newcase indirect_unknown
  $ hg debugobsolete `getid A_0` aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid A_1`
  1 new obsolescence markers
  $ hg debugobsolete `getid A_0` `getid A_2`
  1 new obsolescence markers
  2 new content-divergent changesets
  $ hg log -G --hidden
  *  3:392fd25390da A_2
  |
  | *  2:82623d38b9ba A_1
  |/
  | x  1:007dc284c1f8 A_0 [rewritten as 2:82623d38b9ba; rewritten as 3:392fd25390da]
  |/
  @  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ hg log -r 'contentdivergent()'
  2:82623d38b9ba A_1
  3:392fd25390da A_2
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ cd ..

do not take unknown node in account if they are final
-----------------------------------------------------

  $ newcase final-unknown
  $ hg debugobsolete `getid A_0` `getid A_1`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_1` `getid A_2`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_0` bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  1 new obsolescence markers
  $ hg debugobsolete bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb cccccccccccccccccccccccccccccccccccccccc
  1 new obsolescence markers
  $ hg debugobsolete `getid A_1` dddddddddddddddddddddddddddddddddddddddd
  1 new obsolescence markers

  $ hg debugsuccessorssets --hidden 'desc('A_0')'
  007dc284c1f8
      392fd25390da
  $ hg debugsuccessorssets 'desc('A_0')' --closest
  $ hg debugsuccessorssets 'desc('A_0')' --closest --hidden
  007dc284c1f8
      82623d38b9ba

  $ cd ..

divergence that converge again is not divergence anymore
-----------------------------------------------------

  $ newcase converged_divergence
  $ hg debugobsolete `getid A_0` `getid A_1`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_0` `getid A_2`
  1 new obsolescence markers
  2 new content-divergent changesets
  $ mkcommit A_3
  created new head
  $ hg debugobsolete `getid A_1` `getid A_3`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_2` `getid A_3`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  4:01f36c5a8fda A_3
  |
  | x  3:392fd25390da A_2 [rewritten as 4:01f36c5a8fda]
  |/
  | x  2:82623d38b9ba A_1 [rewritten as 4:01f36c5a8fda]
  |/
  | x  1:007dc284c1f8 A_0 [rewritten as 2:82623d38b9ba; rewritten as 3:392fd25390da]
  |/
  o  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      01f36c5a8fda
  82623d38b9ba
      01f36c5a8fda
  392fd25390da
      01f36c5a8fda
  01f36c5a8fda
      01f36c5a8fda
  $ hg log -r 'contentdivergent()'
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  01f36c5a8fda
      01f36c5a8fda
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba
      392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  01f36c5a8fda
      01f36c5a8fda
  $ cd ..

split is not divergences
-----------------------------

  $ newcase split
  $ hg debugobsolete `getid A_0` `getid A_1` `getid A_2`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  o  3:392fd25390da A_2
  |
  | o  2:82623d38b9ba A_1
  |/
  | x  1:007dc284c1f8 A_0 [split as 2:82623d38b9ba, 3:392fd25390da]
  |/
  @  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba 392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ hg log -r 'contentdivergent()'
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba 392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da

Even when subsequent rewriting happen

  $ mkcommit A_3
  created new head
  $ hg debugobsolete `getid A_1` `getid A_3`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A_4
  created new head
  $ hg debugobsolete `getid A_2` `getid A_4`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A_5
  created new head
  $ hg debugobsolete `getid A_4` `getid A_5`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  6:e442cfc57690 A_5
  |
  | x  5:6a411f0d7a0a A_4 [rewritten as 6:e442cfc57690]
  |/
  | o  4:01f36c5a8fda A_3
  |/
  | x  3:392fd25390da A_2 [rewritten as 5:6a411f0d7a0a]
  |/
  | x  2:82623d38b9ba A_1 [rewritten as 4:01f36c5a8fda]
  |/
  | x  1:007dc284c1f8 A_0 [split as 2:82623d38b9ba, 3:392fd25390da]
  |/
  o  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      01f36c5a8fda e442cfc57690
  82623d38b9ba
      01f36c5a8fda
  392fd25390da
      e442cfc57690
  01f36c5a8fda
      01f36c5a8fda
  6a411f0d7a0a
      e442cfc57690
  e442cfc57690
      e442cfc57690
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  01f36c5a8fda
      01f36c5a8fda
  e442cfc57690
      e442cfc57690
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba 392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  01f36c5a8fda
      01f36c5a8fda
  6a411f0d7a0a
      e442cfc57690
  e442cfc57690
      e442cfc57690
  $ hg log -r 'contentdivergent()'

Check more complex obsolescence graft (with divergence)

  $ mkcommit B_0; hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg debugobsolete `getid B_0` `getid A_2`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ mkcommit A_7; hg up 0
  created new head
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A_8; hg up 0
  created new head
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg debugobsolete `getid A_5` `getid A_7` `getid A_8`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ mkcommit A_9; hg up 0
  created new head
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg debugobsolete `getid A_5` `getid A_9`
  1 new obsolescence markers
  4 new content-divergent changesets
  $ hg log -G --hidden
  *  10:bed64f5d2f5a A_9
  |
  | *  9:14608b260df8 A_8
  |/
  | *  8:7ae126973a96 A_7
  |/
  | x  7:3750ebee865d B_0 [rewritten as 3:392fd25390da]
  | |
  | x  6:e442cfc57690 A_5 [rewritten as 10:bed64f5d2f5a; split as 8:7ae126973a96, 9:14608b260df8]
  |/
  | x  5:6a411f0d7a0a A_4 [rewritten as 6:e442cfc57690]
  |/
  | *  4:01f36c5a8fda A_3
  |/
  | x  3:392fd25390da A_2 [rewritten as 5:6a411f0d7a0a]
  |/
  | x  2:82623d38b9ba A_1 [rewritten as 4:01f36c5a8fda]
  |/
  | x  1:007dc284c1f8 A_0 [split as 2:82623d38b9ba, 3:392fd25390da]
  |/
  @  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      01f36c5a8fda bed64f5d2f5a
      01f36c5a8fda 7ae126973a96 14608b260df8
  82623d38b9ba
      01f36c5a8fda
  392fd25390da
      bed64f5d2f5a
      7ae126973a96 14608b260df8
  01f36c5a8fda
      01f36c5a8fda
  6a411f0d7a0a
      bed64f5d2f5a
      7ae126973a96 14608b260df8
  e442cfc57690
      bed64f5d2f5a
      7ae126973a96 14608b260df8
  3750ebee865d
      bed64f5d2f5a
      7ae126973a96 14608b260df8
  7ae126973a96
      7ae126973a96
  14608b260df8
      14608b260df8
  bed64f5d2f5a
      bed64f5d2f5a
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  01f36c5a8fda
      01f36c5a8fda
  7ae126973a96
      7ae126973a96
  14608b260df8
      14608b260df8
  bed64f5d2f5a
      bed64f5d2f5a
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba 392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  01f36c5a8fda
      01f36c5a8fda
  6a411f0d7a0a
      e442cfc57690
  e442cfc57690
      e442cfc57690
  3750ebee865d
      392fd25390da
  7ae126973a96
      7ae126973a96
  14608b260df8
      14608b260df8
  bed64f5d2f5a
      bed64f5d2f5a
  $ hg log -r 'contentdivergent()'
  4:01f36c5a8fda A_3
  8:7ae126973a96 A_7
  9:14608b260df8 A_8
  10:bed64f5d2f5a A_9

  $ hg log -r bed64f5d2f5a -T '{whyunstable}\n' | sort
  content-divergent: 4:01f36c5a8fda (draft) 8:7ae126973a96 (draft) 9:14608b260df8 (draft) predecessor 007dc284c1f8
  content-divergent: 8:7ae126973a96 (draft) 9:14608b260df8 (draft) predecessor e442cfc57690
  $ hg log -r bed64f5d2f5a -T whyunstableshort | sort
  content-divergent: 4:01f36c5a8fda (draft) 8:7ae126973a96 (draft) 9:14608b260df8 (draft) predecessor 007d
  content-divergent: 8:7ae126973a96 (draft) 9:14608b260df8 (draft) predecessor e442
  $ hg log -r bed64f5d2f5a -T whyunstableshorter | sort
  content-divergent: 01f3 (draft) 7ae1 (draft) 1460 (draft) predecessor 007d
  content-divergent: 7ae1 (draft) 1460 (draft) predecessor e442

fix the divergence

  $ mkcommit A_A; hg up 0
  created new head
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg debugobsolete `getid A_9` `getid A_A`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_7` `getid A_A`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_8` `getid A_A`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  o  11:a139f71be9da A_A
  |
  | x  10:bed64f5d2f5a A_9 [rewritten as 11:a139f71be9da]
  |/
  | x  9:14608b260df8 A_8 [rewritten as 11:a139f71be9da]
  |/
  | x  8:7ae126973a96 A_7 [rewritten as 11:a139f71be9da]
  |/
  | x  7:3750ebee865d B_0 [rewritten as 3:392fd25390da]
  | |
  | x  6:e442cfc57690 A_5 [rewritten as 10:bed64f5d2f5a; split as 8:7ae126973a96, 9:14608b260df8]
  |/
  | x  5:6a411f0d7a0a A_4 [rewritten as 6:e442cfc57690]
  |/
  | o  4:01f36c5a8fda A_3
  |/
  | x  3:392fd25390da A_2 [rewritten as 5:6a411f0d7a0a]
  |/
  | x  2:82623d38b9ba A_1 [rewritten as 4:01f36c5a8fda]
  |/
  | x  1:007dc284c1f8 A_0 [split as 2:82623d38b9ba, 3:392fd25390da]
  |/
  @  0:d20a80d4def3 base
  
  $ hg debugsuccessorssets --hidden 'all()'
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      01f36c5a8fda a139f71be9da
  82623d38b9ba
      01f36c5a8fda
  392fd25390da
      a139f71be9da
  01f36c5a8fda
      01f36c5a8fda
  6a411f0d7a0a
      a139f71be9da
  e442cfc57690
      a139f71be9da
  3750ebee865d
      a139f71be9da
  7ae126973a96
      a139f71be9da
  14608b260df8
      a139f71be9da
  bed64f5d2f5a
      a139f71be9da
  a139f71be9da
      a139f71be9da
  $ hg debugsuccessorssets 'all()' --closest
  d20a80d4def3
      d20a80d4def3
  01f36c5a8fda
      01f36c5a8fda
  a139f71be9da
      a139f71be9da
  $ hg debugsuccessorssets 'all()' --closest --hidden
  d20a80d4def3
      d20a80d4def3
  007dc284c1f8
      82623d38b9ba 392fd25390da
  82623d38b9ba
      82623d38b9ba
  392fd25390da
      392fd25390da
  01f36c5a8fda
      01f36c5a8fda
  6a411f0d7a0a
      e442cfc57690
  e442cfc57690
      e442cfc57690
  3750ebee865d
      392fd25390da
  7ae126973a96
      a139f71be9da
  14608b260df8
      a139f71be9da
  bed64f5d2f5a
      a139f71be9da
  a139f71be9da
      a139f71be9da
  $ hg log -r 'contentdivergent()'

#if serve

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid --config web.view=all \
  >   -A access.log -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS

check an obsolete changeset that was rewritten and also split

  $ get-with-headers.py localhost:$HGPORT 'rev/e442cfc57690?style=paper' | egrep 'rewritten|split'
   <td>rewritten as <a href="/rev/bed64f5d2f5a?style=paper">bed64f5d2f5a</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span><br>
  split as <a href="/rev/7ae126973a96?style=paper">7ae126973a96</a> <a href="/rev/14608b260df8?style=paper">14608b260df8</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></td>
  $ get-with-headers.py localhost:$HGPORT 'rev/e442cfc57690?style=coal' | egrep 'rewritten|split'
   <td>rewritten as <a href="/rev/bed64f5d2f5a?style=coal">bed64f5d2f5a</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span><br>
  split as <a href="/rev/7ae126973a96?style=coal">7ae126973a96</a> <a href="/rev/14608b260df8?style=coal">14608b260df8</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></td>
  $ get-with-headers.py localhost:$HGPORT 'rev/e442cfc57690?style=gitweb' | egrep 'rewritten|split'
  <td>rewritten as <a class="list" href="/rev/bed64f5d2f5a?style=gitweb">bed64f5d2f5a</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></td>
  <td>split as <a class="list" href="/rev/7ae126973a96?style=gitweb">7ae126973a96</a> <a class="list" href="/rev/14608b260df8?style=gitweb">14608b260df8</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></td>
  $ get-with-headers.py localhost:$HGPORT 'rev/e442cfc57690?style=monoblue' | egrep 'rewritten|split'
  <dd>rewritten as <a href="/rev/bed64f5d2f5a?style=monoblue">bed64f5d2f5a</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></dd>
  <dd>split as <a href="/rev/7ae126973a96?style=monoblue">7ae126973a96</a> <a href="/rev/14608b260df8?style=monoblue">14608b260df8</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></dd>
  $ get-with-headers.py localhost:$HGPORT 'rev/e442cfc57690?style=spartan' | egrep 'rewritten|split'
  <td class="obsolete">rewritten as <a href="/rev/bed64f5d2f5a?style=spartan">bed64f5d2f5a</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></td>
  <td class="obsolete">split as <a href="/rev/7ae126973a96?style=spartan">7ae126973a96</a> <a href="/rev/14608b260df8?style=spartan">14608b260df8</a>  by &#116;&#101;&#115;&#116; <span class="age">Thu, 01 Jan 1970 00:00:00 +0000</span></td>

  $ killdaemons.py

#endif

  $ cd ..


Subset does not diverge
------------------------------

Do not report divergent successors-set if it is a subset of another
successors-set. (report [A,B] not [A] + [A,B])

  $ newcase subset
  $ hg debugobsolete `getid A_0` `getid A_2`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete `getid A_0` `getid A_1` `getid A_2`
  1 new obsolescence markers
  $ hg debugsuccessorssets --hidden 'desc('A_0')'
  007dc284c1f8
      82623d38b9ba 392fd25390da
  $ hg debugsuccessorssets 'desc('A_0')' --closest
  $ hg debugsuccessorssets 'desc('A_0')' --closest --hidden
  007dc284c1f8
      82623d38b9ba 392fd25390da

  $ cd ..

Use scmutil.cleanupnodes API to create divergence

  $ hg init cleanupnodes
  $ cd cleanupnodes
  $ hg debugdrawdag <<'EOS'
  >   B1  B3 B4
  >   |     \|
  >   A      Z
  > EOS

  $ hg update -q B1
  $ echo 3 >> B
  $ hg commit --amend -m B2
  $ cat > $TESTTMP/scmutilcleanup.py <<EOF
  > from mercurial import registrar, scmutil
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'cleanup')
  > def cleanup(ui, repo):
  >     def node(expr):
  >         unfi = repo.unfiltered()
  >         rev = unfi.revs(expr).first()
  >         return unfi.changelog.node(rev)
  >     with repo.wlock(), repo.lock(), repo.transaction(b'delayedstrip'):
  >         mapping = {node(b'desc(B1)'): [node(b'desc(B3)')],
  >                    node(b'desc(B3)'): [node(b'desc(B4)')]}
  >         scmutil.cleanupnodes(repo, mapping, b'test')
  > EOF

  $ rm .hg/localtags
  $ hg cleanup --config extensions.t=$TESTTMP/scmutilcleanup.py
  2 new content-divergent changesets
  $ hg log -G -T '{rev}:{node|short} {desc} {instabilities}' -r 'sort(all(), topo)'
  @  5:1a2a9b5b0030 B2 content-divergent
  |
  | *  4:70d5a63ca112 B4 content-divergent
  | |
  | o  1:48b9aae0607f Z
  |
  o  0:426bada5c675 A
  
  $ hg debugobsolete
  a178212c3433c4e77b573f6011e29affb8aefa33 1a2a9b5b0030632400aa78e00388c20f99d3ec44 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '1', 'operation': 'amend', 'user': 'test'}
  a178212c3433c4e77b573f6011e29affb8aefa33 ad6478fb94ecec98b86daae98722865d494ac561 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '13', 'operation': 'test', 'user': 'test'}
  ad6478fb94ecec98b86daae98722865d494ac561 70d5a63ca112acb3764bc1d7320ca90ea688d671 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '9', 'operation': 'test', 'user': 'test'}

  $ hg debugwhyunstable 1a2a9b5b0030
  content-divergent: 70d5a63ca112acb3764bc1d7320ca90ea688d671 (draft) predecessor a178212c3433c4e77b573f6011e29affb8aefa33

  $ hg log -r 1a2a9b5b0030 -T '{whyunstable}\n'
  content-divergent: 4:70d5a63ca112 (draft) predecessor a178212c3433
  $ hg log -r 1a2a9b5b0030 -T whyunstableshort
  content-divergent: 4:70d5a63ca112 (draft) predecessor a178
  $ hg log -r 1a2a9b5b0030 -T whyunstableshorter
  content-divergent: 70d5 (draft) predecessor a178

#if serve

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS

check explanation for a content-divergent changeset

  $ get-with-headers.py localhost:$HGPORT 'rev/1a2a9b5b0030?style=paper' | grep divergent:
   <td>content-divergent: <a href="/rev/70d5a63ca112?style=paper">70d5a63ca112</a> (draft) predecessor <a href="/rev/a178212c3433?style=paper">a178212c3433</a></td>
  $ get-with-headers.py localhost:$HGPORT 'rev/1a2a9b5b0030?style=coal' | grep divergent:
   <td>content-divergent: <a href="/rev/70d5a63ca112?style=coal">70d5a63ca112</a> (draft) predecessor <a href="/rev/a178212c3433?style=coal">a178212c3433</a></td>
  $ get-with-headers.py localhost:$HGPORT 'rev/1a2a9b5b0030?style=gitweb' | grep divergent:
  <td>content-divergent: <a class="list" href="/rev/70d5a63ca112?style=gitweb">70d5a63ca112</a> (draft) predecessor <a class="list" href="/rev/a178212c3433?style=gitweb">a178212c3433</a></td>
  $ get-with-headers.py localhost:$HGPORT 'rev/1a2a9b5b0030?style=monoblue' | grep divergent:
  <dd>content-divergent: <a href="/rev/70d5a63ca112?style=monoblue">70d5a63ca112</a> (draft) predecessor <a href="/rev/a178212c3433?style=monoblue">a178212c3433</a></dd>
  $ get-with-headers.py localhost:$HGPORT 'rev/1a2a9b5b0030?style=spartan' | grep divergent:
  <td class="unstable">content-divergent: <a href="/rev/70d5a63ca112?style=spartan">70d5a63ca112</a> (draft) predecessor <a href="/rev/a178212c3433?style=spartan">a178212c3433</a></td>

  $ killdaemons.py

#endif