tests/test-git-interop.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

#require pygit2

Setup:
  $ GIT_AUTHOR_NAME='test'; export GIT_AUTHOR_NAME
  > GIT_AUTHOR_EMAIL='[e-mail]'; export GIT_AUTHOR_EMAIL
  > GIT_AUTHOR_DATE="2007-01-01 00:00:00 +0000"; export GIT_AUTHOR_DATE
  > GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"; export GIT_COMMITTER_NAME
  > GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL"; export GIT_COMMITTER_EMAIL
  > GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"; export GIT_COMMITTER_DATE
  > count=10
  > gitcommit() {
  >    GIT_AUTHOR_DATE="2007-01-01 00:00:$count +0000";
  >    GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
  >    git commit "$@" >/dev/null 2>/dev/null || echo "git commit error"
  >    count=`expr $count + 1`
  >  }


  $ hg version -v --config extensions.git= | grep '^[E ]'
  Enabled extensions:
    git  internal  (pygit2 *) (glob)

Test auto-loading extension works:
  $ mkdir nogit
  $ cd nogit
  $ mkdir .hg
  $ echo git >> .hg/requires
  $ hg status
  abort: repository specified git format in .hg/requires but has no .git directory
  [255]
  $ git init
  Initialized empty Git repository in $TESTTMP/nogit/.git/
  $ git config --global init.defaultBranch master
This status invocation shows some hg gunk because we didn't use
`hg init --git`, which fixes up .git/info/exclude for us.
  $ hg status
  ? .hg/cache/git-commits.sqlite
  ? .hg/cache/git-commits.sqlite-shm
  ? .hg/cache/git-commits.sqlite-wal
  ? .hg/requires
  $ cd ..

Now globally enable extension for the rest of the test:
  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > git=
  > [git]
  > log-index-cache-miss = yes
  > EOF

Make a new repo with git:
  $ mkdir foo
  $ cd foo
  $ git init
  Initialized empty Git repository in $TESTTMP/foo/.git/
Ignore the .hg directory within git:
  $ echo .hg >> .git/info/exclude
  $ echo alpha > alpha
  $ git add alpha
  $ gitcommit -am 'Add alpha'
  $ echo beta > beta
  $ git add beta
  $ gitcommit -am 'Add beta'
  $ echo gamma > gamma
  $ git status
  On branch master
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
  	gamma
  
  nothing added to commit but untracked files present (use "git add" to track)

Without creating the .hg, hg status fails:
  $ hg status
  abort: no repository found in '$TESTTMP/foo' (.hg not found)
  [10]
But if you run hg init --git, it works:
  $ hg init --git
  $ hg id --traceback
  heads mismatch, rebuilding dagcache
  3d9be8deba43 tip master
  $ hg status
  ? gamma
Log works too:
  $ hg log
  changeset:   1:3d9be8deba43
  bookmark:    master
  tag:         tip
  user:        test <[e-mail]>
  date:        Mon Jan 01 00:00:11 2007 +0000
  summary:     Add beta
  
  changeset:   0:c5864c9d16fb
  user:        test <[e-mail]>
  date:        Mon Jan 01 00:00:10 2007 +0000
  summary:     Add alpha
  


and bookmarks:
  $ hg bookmarks
   * master                    1:3d9be8deba43

diff even works transparently in both systems:
  $ echo blah >> alpha
  $ git diff
  diff --git a/alpha b/alpha
  index 4a58007..faed1b7 100644
  --- a/alpha
  +++ b/alpha
  @@ -1* +1,2 @@ (glob)
   alpha
  +blah
  $ hg diff --git
  diff --git a/alpha b/alpha
  --- a/alpha
  +++ b/alpha
  @@ -1,1 +1,2 @@
   alpha
  +blah

Remove a file, it shows as such:
  $ rm alpha
  $ hg status
  ! alpha
  ? gamma

Revert works:
  $ hg revert alpha --traceback
  $ hg status
  ? gamma
  $ git status
  On branch master
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
  	gamma
  
  nothing added to commit but untracked files present (use "git add" to track)

Add shows sanely in both:
  $ hg add gamma
  $ hg status
  A gamma
  $ hg files
  alpha
  beta
  gamma
  $ git ls-files
  alpha
  beta
  gamma
  $ git status
  On branch master
  Changes to be committed:
    (use "git restore --staged <file>..." to unstage)
  	new file:   gamma
  

forget does what it should as well:
  $ hg forget gamma
  $ hg status
  ? gamma
  $ git status
  On branch master
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
  	gamma
  
  nothing added to commit but untracked files present (use "git add" to track)

clean up untracked file
  $ rm gamma

hg log FILE

  $ echo a >> alpha
  $ hg ci -m 'more alpha' --traceback --date '1583522787 18000'
  $ echo b >> beta
  $ hg ci -m 'more beta'
  heads mismatch, rebuilding dagcache
  $ echo a >> alpha
  $ hg ci -m 'even more alpha'
  heads mismatch, rebuilding dagcache
  $ hg log -G alpha
  heads mismatch, rebuilding dagcache
  @  changeset:   4:6626247b7dc8
  :  bookmark:    master
  :  tag:         tip
  :  user:        test <test>
  :  date:        Thu Jan 01 00:00:00 1970 +0000
  :  summary:     even more alpha
  :
  o  changeset:   2:a1983dd7fb19
  :  user:        test <test>
  :  date:        Fri Mar 06 14:26:27 2020 -0500
  :  summary:     more alpha
  :
  o  changeset:   0:c5864c9d16fb
     user:        test <[e-mail]>
     date:        Mon Jan 01 00:00:10 2007 +0000
     summary:     Add alpha
  
  $ hg log -G beta
  o  changeset:   3:d8ee22687733
  :  user:        test <test>
  :  date:        Thu Jan 01 00:00:00 1970 +0000
  :  summary:     more beta
  :
  o  changeset:   1:3d9be8deba43
  |  user:        test <[e-mail]>
  ~  date:        Mon Jan 01 00:00:11 2007 +0000
     summary:     Add beta
  

  $ hg log -r "children(3d9be8deba43)" -T"{node|short} {children}\n"
  a1983dd7fb19 3:d8ee22687733

hg annotate

  $ hg annotate alpha
  0: alpha
  2: a
  4: a
  $ hg annotate beta
  1: beta
  3: b


Files in subdirectories. TODO: case-folding support, make this `A`
instead of `a`.

  $ mkdir a
  $ echo "This is file mu." > a/mu
  $ hg ci -A -m 'Introduce file a/mu'
  adding a/mu

Both hg and git agree a/mu is part of the repo

  $ git ls-files
  a/mu
  alpha
  beta
  $ hg files
  a/mu
  alpha
  beta

hg and git status both clean

  $ git status
  On branch master
  nothing to commit, working tree clean
  $ hg status
  heads mismatch, rebuilding dagcache


node|shortest works correctly
  $ hg log -T '{node}\n' | sort
  3d9be8deba43482be2c81a4cb4be1f10d85fa8bc
  6626247b7dc8f231b183b8a4761c89139baca2ad
  a1983dd7fb19cbd83ad5a1c2fc8bf3d775dea12f
  ae1ab744f95bfd5b07cf573baef98a778058537b
  c5864c9d16fb3431fe2c175ff84dc6accdbb2c18
  d8ee22687733a1991813560b15128cd9734f4b48
  $ hg log -r ae1ab744f95bfd5b07cf573baef98a778058537b --template "{shortest(node,1)}\n"
  ae

This coveres changelog.findmissing()
  $ hg merge --preview 3d9be8deba43

This covers manifest.diff()
  $ hg diff -c 3d9be8deba43
  diff -r c5864c9d16fb -r 3d9be8deba43 beta
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/beta	Mon Jan 01 00:00:11 2007 +0000
  @@ -0,0 +1,1 @@
  +beta


Interactive commit should work as expected

  $ echo bar >> alpha
  $ echo bar >> beta
  $ hg commit -m "test interactive commit" -i --config ui.interactive=true --config ui.interface=text << EOF
  > y
  > y
  > n
  > EOF
  diff --git a/alpha b/alpha
  1 hunks, 1 lines changed
  examine changes to 'alpha'?
  (enter ? for help) [Ynesfdaq?] y
  
  @@ -1,3 +1,4 @@
   alpha
   a
   a
  +bar
  record change 1/2 to 'alpha'?
  (enter ? for help) [Ynesfdaq?] y
  
  diff --git a/beta b/beta
  1 hunks, 1 lines changed
  examine changes to 'beta'?
  (enter ? for help) [Ynesfdaq?] n
  
Status should be consistent for both systems

  $ hg status
  heads mismatch, rebuilding dagcache
  M beta
  $ git status | egrep -v '^$|^  \(use '
  On branch master
  Changes not staged for commit:
  	modified:   beta
  no changes added to commit (use "git add" and/or "git commit -a")

Contents of each commit should be the same

  $ hg ex -r .
  # HG changeset patch
  # User test <test>
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 80adc61cf57e99f6a412d83fee6239d1556cefcf
  # Parent  ae1ab744f95bfd5b07cf573baef98a778058537b
  test interactive commit
  
  diff -r ae1ab744f95b -r 80adc61cf57e alpha
  --- a/alpha	Thu Jan 01 00:00:00 1970 +0000
  +++ b/alpha	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,3 +1,4 @@
   alpha
   a
   a
  +bar
  $ git show
  commit 80adc61cf57e99f6a412d83fee6239d1556cefcf
  Author: test <test>
  Date:   Thu Jan 1 00:00:00 1970 +0000
  
      test interactive commit
  
  diff --git a/alpha b/alpha
  index d112a75..d2a2e9a 100644
  --- a/alpha
  +++ b/alpha
  @@ -1,3 +1,4 @@
   alpha
   a
   a
  +bar

Deleting files should also work (this was issue6398)
  $ hg revert -r . --all
  reverting beta
  $ hg rm beta
  $ hg ci -m 'remove beta'