tests/test-bheads.t

copies-rust: parse the changed-file sidedata directly in rust

It does not make much sense to parse the data into python object using slow
python code to later turn them into rust object. We directly pass the binary
blob and use it directly in Rust.

Ideally we could directly read the sidedata in Rust, using a revlog in Rust.
However we do not have this ready to use yet.

This more direct approach provides a nice speedup over the board. Especially five
cases that we previously too slow to return in the previous changeset are not
able to finish.

Notably, we are now significantly faster than the Python version of this code in
all the meaningful cases.

I looked at the various cases that remains significantly slower then the filelog
version and they are currently 3 main source of slowness:

* The isancestor computation: even if we cache them, if the revs spawn over a
  large amount of history the ancestry checking is still quite expensive. Using
  a different approach more centered on the graph we are currently considering
  might yield significant speed.

* Merging of the map from the two parents: in some case, this climb up to ⅔ of
  the time spent in copy tracing. See inline comment for idea to handle this
  better.

* Extracting data from the filelog. I would like to think this mostly comes from
  the fact my test repositories pre-date Valentin Gatien-Baron improvement of
  the `files` field (99ebde4fec99) and that more recent revisions will be faster
  to fetch. Further testing on this aspect is needed.

This revision compared to the previous 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,   0.000047 s,   0.000049 s,  +0.000002 s, × 1.0426,    49 µs/rev
mercurial       x_revs_x_added_x_copies               2b1c78674230 0c1d10351869 :      6 revs,   0.000181 s,   0.000114 s,  -0.000067 s, × 0.6298,    19 µs/rev
mercurial       x000_revs_x000_added_x_copies         81f8ff2a9bf2 dd3267698d84 :   1032 revs,   0.005852 s,   0.004223 s,  -0.001629 s, × 0.7216,     4 µs/rev
pypy            x_revs_x_added_0_copies               aed021ee8ae8 099ed31b181b :      9 revs,   0.000229 s,   0.000305 s,  +0.000076 s, × 1.3319,    33 µs/rev
pypy            x_revs_x000_added_0_copies            4aa4e1f8e19a 359343b9ac0e :      1 revs,   0.000058 s,   0.000060 s,  +0.000002 s, × 1.0345,    60 µs/rev
pypy            x_revs_x_added_x_copies               ac52eb7bbbb0 72e022663155 :      7 revs,   0.000146 s,   0.000173 s,  +0.000027 s, × 1.1849,    24 µs/rev
pypy            x_revs_x00_added_x_copies             c3b14617fbd7 ace7255d9a26 :      1 revs,   0.001206 s,   0.000446 s,  -0.000760 s, × 0.3698,   446 µs/rev
pypy            x_revs_x000_added_x000_copies         df6f7a526b60 a83dc6a2d56f :      6 revs,   0.025275 s,   0.010360 s,  -0.014915 s, × 0.4099,  1726 µs/rev
pypy            x000_revs_xx00_added_0_copies         89a76aede314 2f22446ff07e :   4785 revs,   0.080303 s,   0.048002 s,  -0.032301 s, × 0.5978,    10 µs/rev
pypy            x000_revs_x000_added_x_copies         8a3b5bfd266e 2c68e87c3efe :   6780 revs,   0.152641 s,   0.075705 s,  -0.076936 s, × 0.4960,    11 µs/rev
pypy            x000_revs_x000_added_x000_copies      89a76aede314 7b3dda341c84 :   5441 revs,   0.099107 s,   0.056705 s,  -0.042402 s, × 0.5722,    10 µs/rev
pypy            x0000_revs_x_added_0_copies           d1defd0dc478 c9cb1334cc78 :  43646 revs,   2.137894 s,   0.794685 s,  -1.343209 s, × 0.3717,    18 µs/rev
pypy            x0000_revs_xx000_added_0_copies       bf2c629d0071 4ffed77c095c :  26389 revs,   0.022202 s,   0.020209 s,  -0.001993 s, × 0.9102,     0 µs/rev
pypy            x0000_revs_xx000_added_x000_copies    08ea3258278e d9fa043f30c0 :  11316 revs,   0.228946 s,   0.122475 s,  -0.106471 s, × 0.5350,    10 µs/rev
netbeans        x_revs_x_added_0_copies               fb0955ffcbcd a01e9239f9e7 :      2 revs,   0.000186 s,   0.000142 s,  -0.000044 s, × 0.7634,    71 µs/rev
netbeans        x_revs_x000_added_0_copies            6f360122949f 20eb231cc7d0 :      2 revs,   0.000133 s,   0.000113 s,  -0.000020 s, × 0.8496,    56 µs/rev
netbeans        x_revs_x_added_x_copies               1ada3faf6fb6 5a39d12eecf4 :      3 revs,   0.000320 s,   0.000241 s,  -0.000079 s, × 0.7531,    80 µs/rev
netbeans        x_revs_x00_added_x_copies             35be93ba1e2c 9eec5e90c05f :      9 revs,   0.001339 s,   0.000729 s,  -0.000610 s, × 0.5444,    81 µs/rev
netbeans        x000_revs_xx00_added_0_copies         eac3045b4fdd 51d4ae7f1290 :   1421 revs,   0.015694 s,   0.010198 s,  -0.005496 s, × 0.6498,     7 µs/rev
netbeans        x000_revs_x000_added_x_copies         e2063d266acd 6081d72689dc :   1533 revs,   0.018457 s,   0.015312 s,  -0.003145 s, × 0.8296,     9 µs/rev
netbeans        x000_revs_x000_added_x000_copies      ff453e9fee32 411350406ec2 :   5750 revs,   0.111691 s,   0.060517 s,  -0.051174 s, × 0.5418,    10 µs/rev
netbeans        x0000_revs_xx000_added_x000_copies    588c2d1ced70 1aad62e59ddd :  67005 revs,   1.166017 s,   0.611102 s,  -0.554915 s, × 0.5241,     9 µs/rev
mozilla-central x_revs_x_added_0_copies               3697f962bb7b 7015fcdd43a2 :      2 revs,   0.000197 s,   0.000164 s,  -0.000033 s, × 0.8325,    82 µs/rev
mozilla-central x_revs_x000_added_0_copies            dd390860c6c9 40d0c5bed75d :      8 revs,   0.000626 s,   0.000334 s,  -0.000292 s, × 0.5335,    41 µs/rev
mozilla-central x_revs_x_added_x_copies               8d198483ae3b 14207ffc2b2f :      9 revs,   0.000303 s,   0.000463 s,  +0.000160 s, × 1.5281,    51 µs/rev
mozilla-central x_revs_x00_added_x_copies             98cbc58cc6bc 446a150332c3 :      7 revs,   0.001679 s,   0.000730 s,  -0.000949 s, × 0.4348,   104 µs/rev
mozilla-central x_revs_x000_added_x000_copies         3c684b4b8f68 0a5e72d1b479 :      3 revs,   0.006947 s,   0.003522 s,  -0.003425 s, × 0.5070,  1174 µs/rev
mozilla-central x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.133070 s,   0.072518 s,  -0.060552 s, × 0.5450, 12086 µs/rev
mozilla-central x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.008705 s,   0.005760 s,  -0.002945 s, × 0.6617,     3 µs/rev
mozilla-central x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :   8315 revs,   0.005913 s,   0.005720 s,  -0.000193 s, × 0.9674,     0 µs/rev
mozilla-central x000_revs_x000_added_x000_copies      7c97034feb78 4407bd0c6330 :   7839 revs,   0.101373 s,   0.063310 s,  -0.038063 s, × 0.6245,     8 µs/rev
mozilla-central x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :  45299 revs,   0.046526 s,   0.043608 s,  -0.002918 s, × 0.9373,     0 µs/rev
mozilla-central x0000_revs_xx000_added_x000_copies    f78c615a656c 96a38b690156 :  30263 revs,   0.313954 s,   0.204831 s,  -0.109123 s, × 0.6524,     6 µs/rev
mozilla-central x00000_revs_x0000_added_x0000_copies  6832ae71433c 4c222a1d9a00 : 153721 revs,   3.367395 s,   2.161906 s,  -1.205489 s, × 0.6420,    14 µs/rev
mozilla-central x00000_revs_x00000_added_x000_copies  76caed42cf7c 1daa622bbe42 : 210546 revs,   4.691820 s,   3.291831 s,  -1.399989 s, × 0.7016,    15 µs/rev
mozilla-try     x_revs_x_added_0_copies               aaf6dde0deb8 9790f499805a :      2 revs,   0.001199 s,   0.001213 s,  +0.000014 s, × 1.0117,   606 µs/rev
mozilla-try     x_revs_x000_added_0_copies            d8d0222927b4 5bb8ce8c7450 :      2 revs,   0.001216 s,   0.001225 s,  +0.000009 s, × 1.0074,   612 µs/rev
mozilla-try     x_revs_x_added_x_copies               092fcca11bdb 936255a0384a :      4 revs,   0.000613 s,   0.000564 s,  -0.000049 s, × 0.9201,   141 µs/rev
mozilla-try     x_revs_x00_added_x_copies             b53d2fadbdb5 017afae788ec :      2 revs,   0.001906 s,   0.001549 s,  -0.000357 s, × 0.8127,   774 µs/rev
mozilla-try     x_revs_x000_added_x000_copies         20408ad61ce5 6f0ee96e21ad :      1 revs,   0.092766 s,   0.035918 s,  -0.056848 s, × 0.3872, 35918 µs/rev
mozilla-try     x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.136074 s,   0.073788 s,  -0.062286 s, × 0.5423, 12298 µs/rev
mozilla-try     x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.009067 s,   0.006151 s,  -0.002916 s, × 0.6784,     3 µs/rev
mozilla-try     x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :   8315 revs,   0.006243 s,   0.006165 s,  -0.000078 s, × 0.9875,     0 µs/rev
mozilla-try     x000_revs_x000_added_x000_copies      1346fd0130e4 4c65cbdabc1f :   6657 revs,   0.114463 s,   0.065421 s,  -0.049042 s, × 0.5715,     9 µs/rev
mozilla-try     x0000_revs_x_added_0_copies           63519bfd42ee a36a2a865d92 :  40314 revs,   0.433683 s,   0.313749 s,  -0.119934 s, × 0.7235,     7 µs/rev
mozilla-try     x0000_revs_x_added_x_copies           9fe69ff0762d bcabf2a78927 :  38690 revs,   0.411278 s,   0.297867 s,  -0.113411 s, × 0.7242,     7 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :  54487 revs,   0.155133 s,   0.111300 s,  -0.043833 s, × 0.7174,     2 µs/rev
mozilla-try     x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :  45299 revs,   0.048933 s,   0.046202 s,  -0.002731 s, × 0.9442,     1 µs/rev
mozilla-try     x0000_revs_xx000_added_x000_copies    89294cd501d9 7ccb2fc7ccb5 :  97052 revs,   8.100385 s,   1.999640 s,  -6.100745 s, × 0.2469,    20 µs/rev
mozilla-try     x0000_revs_x0000_added_x0000_copies   e928c65095ed e951f4ad123a :  52031 revs,   1.446720 s,   0.809134 s,  -0.637586 s, × 0.5593,    15 µs/rev
mozilla-try     x00000_revs_x_added_0_copies          6a320851d377 1ebb79acd503 : 363753 revs, killed      ,  47.406785 s,             ,         ,   130 µs/rev
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c : 444327 revs,   1.369537 s,   0.996219 s,  -0.373318 s, × 0.7274,     2 µs/rev
mozilla-try     x00000_revs_x_added_x_copies          5173c4b6f97c 95d83ee7242d : 362229 revs, killed      ,  47.273399 s,             ,         ,   130 µs/rev
mozilla-try     x00000_revs_x000_added_x_copies       9126823d0e9c ca82787bb23c : 359344 revs, killed      ,  47.419099 s,             ,         ,   131 µs/rev
mozilla-try     x00000_revs_x0000_added_x0000_copies  8d3fafa80d4b eb884023b810 : 192665 revs,   5.186079 s,   3.512653 s,  -1.673426 s, × 0.6773,    18 µs/rev
mozilla-try     x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 237259 revs, killed      ,  44.459049 s,             ,         ,   187 µs/rev
mozilla-try     x00000_revs_x00000_added_x000_copies  9b2a99adc05e 8e29777b48e6 : 391148 revs, killed      ,  52.837926 s,             ,         ,   135 µs/rev

This revision compared to the python code:
==========================================

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  Python-Time  Rust-Time    Difference    Factor    time per rev
--------------------------------------------------------------------------------------------------------------------------------------------------------------
mercurial       x_revs_x_added_0_copies               ad6b123de1c7 39cfcef4f463 :      1 revs,   0.000044 s,   0.000049 s,  +0.000005 s, × 1.1136,    49 µs/rev
mercurial       x_revs_x_added_x_copies               2b1c78674230 0c1d10351869 :      6 revs,   0.000138 s,   0.000114 s,  -0.000024 s, × 0.8261,    19 µs/rev
mercurial       x000_revs_x000_added_x_copies         81f8ff2a9bf2 dd3267698d84 :   1032 revs,   0.005052 s,   0.004223 s,  -0.000829 s, × 0.8359,     4 µs/rev
pypy            x_revs_x_added_0_copies               aed021ee8ae8 099ed31b181b :      9 revs,   0.000219 s,   0.000305 s,  +0.000086 s, × 1.3927,    33 µs/rev
pypy            x_revs_x000_added_0_copies            4aa4e1f8e19a 359343b9ac0e :      1 revs,   0.000055 s,   0.000060 s,  +0.000005 s, × 1.0909,    60 µs/rev
pypy            x_revs_x_added_x_copies               ac52eb7bbbb0 72e022663155 :      7 revs,   0.000128 s,   0.000173 s,  +0.000045 s, × 1.3516,    24 µs/rev
pypy            x_revs_x00_added_x_copies             c3b14617fbd7 ace7255d9a26 :      1 revs,   0.001089 s,   0.000446 s,  -0.000643 s, × 0.4096,   446 µs/rev
pypy            x_revs_x000_added_x000_copies         df6f7a526b60 a83dc6a2d56f :      6 revs,   0.017407 s,   0.010360 s,  -0.007047 s, × 0.5952,  1726 µs/rev
pypy            x000_revs_xx00_added_0_copies         89a76aede314 2f22446ff07e :   4785 revs,   0.094175 s,   0.048002 s,  -0.046173 s, × 0.5097,    10 µs/rev
pypy            x000_revs_x000_added_x_copies         8a3b5bfd266e 2c68e87c3efe :   6780 revs,   0.238009 s,   0.075705 s,  -0.162304 s, × 0.3181,    11 µs/rev
pypy            x000_revs_x000_added_x000_copies      89a76aede314 7b3dda341c84 :   5441 revs,   0.125876 s,   0.056705 s,  -0.069171 s, × 0.4505,    10 µs/rev
pypy            x0000_revs_x_added_0_copies           d1defd0dc478 c9cb1334cc78 :  43646 revs,   3.581556 s,   0.794685 s,  -2.786871 s, × 0.2219,    18 µs/rev
pypy            x0000_revs_xx000_added_0_copies       bf2c629d0071 4ffed77c095c :  26389 revs,   0.016721 s,   0.020209 s,  +0.003488 s, × 1.2086,     0 µs/rev
pypy            x0000_revs_xx000_added_x000_copies    08ea3258278e d9fa043f30c0 :  11316 revs,   0.242367 s,   0.122475 s,  -0.119892 s, × 0.5053,    10 µs/rev
netbeans        x_revs_x_added_0_copies               fb0955ffcbcd a01e9239f9e7 :      2 revs,   0.000165 s,   0.000142 s,  -0.000023 s, × 0.8606,    71 µs/rev
netbeans        x_revs_x000_added_0_copies            6f360122949f 20eb231cc7d0 :      2 revs,   0.000114 s,   0.000113 s,  -0.000001 s, × 0.9912,    56 µs/rev
netbeans        x_revs_x_added_x_copies               1ada3faf6fb6 5a39d12eecf4 :      3 revs,   0.000296 s,   0.000241 s,  -0.000055 s, × 0.8142,    80 µs/rev
netbeans        x_revs_x00_added_x_copies             35be93ba1e2c 9eec5e90c05f :      9 revs,   0.001124 s,   0.000729 s,  -0.000395 s, × 0.6486,    81 µs/rev
netbeans        x000_revs_xx00_added_0_copies         eac3045b4fdd 51d4ae7f1290 :   1421 revs,   0.013060 s,   0.010198 s,  -0.002862 s, × 0.7809,     7 µs/rev
netbeans        x000_revs_x000_added_x_copies         e2063d266acd 6081d72689dc :   1533 revs,   0.017112 s,   0.015312 s,  -0.001800 s, × 0.8948,     9 µs/rev
netbeans        x000_revs_x000_added_x000_copies      ff453e9fee32 411350406ec2 :   5750 revs,   0.660350 s,   0.060517 s,  -0.599833 s, × 0.0916,    10 µs/rev
netbeans        x0000_revs_xx000_added_x000_copies    588c2d1ced70 1aad62e59ddd :  67005 revs,  10.032499 s,   0.611102 s,  -9.421397 s, × 0.0609,     9 µs/rev
mozilla-central x_revs_x_added_0_copies               3697f962bb7b 7015fcdd43a2 :      2 revs,   0.000189 s,   0.000164 s,  -0.000025 s, × 0.8677,    82 µs/rev
mozilla-central x_revs_x000_added_0_copies            dd390860c6c9 40d0c5bed75d :      8 revs,   0.000462 s,   0.000334 s,  -0.000128 s, × 0.7229,    41 µs/rev
mozilla-central x_revs_x_added_x_copies               8d198483ae3b 14207ffc2b2f :      9 revs,   0.000270 s,   0.000463 s,  +0.000193 s, × 1.7148,    51 µs/rev
mozilla-central x_revs_x00_added_x_copies             98cbc58cc6bc 446a150332c3 :      7 revs,   0.001474 s,   0.000730 s,  -0.000744 s, × 0.4953,   104 µs/rev
mozilla-central x_revs_x000_added_x000_copies         3c684b4b8f68 0a5e72d1b479 :      3 revs,   0.004806 s,   0.003522 s,  -0.001284 s, × 0.7328,  1174 µs/rev
mozilla-central x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.085150 s,   0.072518 s,  -0.012632 s, × 0.8517, 12086 µs/rev
mozilla-central x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.007064 s,   0.005760 s,  -0.001304 s, × 0.8154,     3 µs/rev
mozilla-central x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :   8315 revs,   0.004741 s,   0.005720 s,  +0.000979 s, × 1.2065,     0 µs/rev
mozilla-central x000_revs_x000_added_x000_copies      7c97034feb78 4407bd0c6330 :   7839 revs,   0.190133 s,   0.063310 s,  -0.126823 s, × 0.3330,     8 µs/rev
mozilla-central x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :  45299 revs,   0.035651 s,   0.043608 s,  +0.007957 s, × 1.2232,     0 µs/rev
mozilla-central x0000_revs_xx000_added_x000_copies    f78c615a656c 96a38b690156 :  30263 revs,   0.440694 s,   0.204831 s,  -0.235863 s, × 0.4648,     6 µs/rev
mozilla-central x00000_revs_x0000_added_x0000_copies  6832ae71433c 4c222a1d9a00 : 153721 revs,  18.454163 s,   2.161906 s, -16.292257 s, × 0.1172,    14 µs/rev
mozilla-central x00000_revs_x00000_added_x000_copies  76caed42cf7c 1daa622bbe42 : 210546 revs,  31.562719 s,   3.291831 s, -28.270888 s, × 0.1043,    15 µs/rev
mozilla-try     x_revs_x_added_0_copies               aaf6dde0deb8 9790f499805a :      2 revs,   0.001189 s,   0.001213 s,  +0.000024 s, × 1.0202,   606 µs/rev
mozilla-try     x_revs_x000_added_0_copies            d8d0222927b4 5bb8ce8c7450 :      2 revs,   0.001204 s,   0.001225 s,  +0.000021 s, × 1.0174,   612 µs/rev
mozilla-try     x_revs_x_added_x_copies               092fcca11bdb 936255a0384a :      4 revs,   0.000586 s,   0.000564 s,  -0.000022 s, × 0.9625,   141 µs/rev
mozilla-try     x_revs_x00_added_x_copies             b53d2fadbdb5 017afae788ec :      2 revs,   0.001845 s,   0.001549 s,  -0.000296 s, × 0.8396,   774 µs/rev
mozilla-try     x_revs_x000_added_x000_copies         20408ad61ce5 6f0ee96e21ad :      1 revs,   0.063822 s,   0.035918 s,  -0.027904 s, × 0.5628, 35918 µs/rev
mozilla-try     x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   0.088038 s,   0.073788 s,  -0.014250 s, × 0.8381, 12298 µs/rev
mozilla-try     x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.007389 s,   0.006151 s,  -0.001238 s, × 0.8325,     3 µs/rev
mozilla-try     x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :   8315 revs,   0.004868 s,   0.006165 s,  +0.001297 s, × 1.2664,     0 µs/rev
mozilla-try     x000_revs_x000_added_x000_copies      1346fd0130e4 4c65cbdabc1f :   6657 revs,   0.222450 s,   0.065421 s,  -0.157029 s, × 0.2941,     9 µs/rev
mozilla-try     x0000_revs_x_added_0_copies           63519bfd42ee a36a2a865d92 :  40314 revs,   0.370675 s,   0.313749 s,  -0.056926 s, × 0.8464,     7 µs/rev
mozilla-try     x0000_revs_x_added_x_copies           9fe69ff0762d bcabf2a78927 :  38690 revs,   0.358020 s,   0.297867 s,  -0.060153 s, × 0.8320,     7 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :  54487 revs,   0.145235 s,   0.111300 s,  -0.033935 s, × 0.7663,     2 µs/rev
mozilla-try     x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :  45299 revs,   0.037606 s,   0.046202 s,  +0.008596 s, × 1.2286,     1 µs/rev
mozilla-try     x0000_revs_xx000_added_x000_copies    89294cd501d9 7ccb2fc7ccb5 :  97052 revs,   7.382439 s,   1.999640 s,  -5.382799 s, × 0.2709,    20 µs/rev
mozilla-try     x0000_revs_x0000_added_x0000_copies   e928c65095ed e951f4ad123a :  52031 revs,   7.273506 s,   0.809134 s,  -6.464372 s, × 0.1112,    15 µs/rev
mozilla-try     x00000_revs_x_added_0_copies          6a320851d377 1ebb79acd503 : 363753 revs, killed      ,  47.406785 s,             ,         ,   130 µs/rev
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c : 444327 revs,   1.074593 s,   0.996219 s,  -0.078374 s, × 0.9271,     2 µs/rev
mozilla-try     x00000_revs_x_added_x_copies          5173c4b6f97c 95d83ee7242d : 362229 revs, killed      ,  47.273399 s,             ,         ,   130 µs/rev
mozilla-try     x00000_revs_x000_added_x_copies       9126823d0e9c ca82787bb23c : 359344 revs, killed      ,  47.419099 s,             ,         ,   131 µs/rev
mozilla-try     x00000_revs_x0000_added_x0000_copies  8d3fafa80d4b eb884023b810 : 192665 revs,  27.746195 s,   3.512653 s, -24.233542 s, × 0.1266,    18 µs/rev
mozilla-try     x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 237259 revs, killed      ,  44.459049 s,             ,         ,   187 µs/rev
mozilla-try     x00000_revs_x00000_added_x000_copies  9b2a99adc05e 8e29777b48e6 : 391148 revs, killed      ,  52.837926 s,             ,         ,   135 µs/rev


This revision compared to the filelog algorithm:
================================================

Repo            Case                                  Source-Rev   Dest-Rev      # of revisions  filelog     sidedata      Difference    Factor    time per rev
--------------------------------------------------------------------------------------------------------------------------------------------------------------
mercurial       x_revs_x_added_0_copies               ad6b123de1c7 39cfcef4f463 :      1 revs,   0.000906 s,   0.000049 s,  -0.000857 s, × 0.0540,     48 µs/rev
mercurial       x_revs_x_added_x_copies               2b1c78674230 0c1d10351869 :      6 revs,   0.001844 s,   0.000114 s,  -0.001730 s, × 0.0618,     18 µs/rev
mercurial       x000_revs_x000_added_x_copies         81f8ff2a9bf2 dd3267698d84 :   1032 revs,   0.018577 s,   0.004223 s,  -0.014354 s, × 0.2273,      4 µs/rev
pypy            x_revs_x_added_0_copies               aed021ee8ae8 099ed31b181b :      9 revs,   0.005009 s,   0.000305 s,  -0.004704 s, × 0.0608,     33 µs/rev
pypy            x_revs_x000_added_0_copies            4aa4e1f8e19a 359343b9ac0e :      1 revs,   0.209606 s,   0.000060 s,  -0.209546 s, × 0.0002,     59 µs/rev
pypy            x_revs_x_added_x_copies               ac52eb7bbbb0 72e022663155 :      7 revs,   0.017008 s,   0.000173 s,  -0.016835 s, × 0.0101,     24 µs/rev
pypy            x_revs_x00_added_x_copies             c3b14617fbd7 ace7255d9a26 :      1 revs,   0.019227 s,   0.000446 s,  -0.018781 s, × 0.0231,    445 µs/rev
pypy            x_revs_x000_added_x000_copies         df6f7a526b60 a83dc6a2d56f :      6 revs,   0.765782 s,   0.010360 s,  -0.755422 s, × 0.0135,   1726 µs/rev
pypy            x000_revs_xx00_added_0_copies         89a76aede314 2f22446ff07e :   4785 revs,   1.186068 s,   0.048002 s,  -1.138066 s, × 0.0404,     10 µs/rev
pypy            x000_revs_x000_added_x_copies         8a3b5bfd266e 2c68e87c3efe :   6780 revs,   1.266745 s,   0.075705 s,  -1.191040 s, × 0.0597,     11 µs/rev
pypy            x000_revs_x000_added_x000_copies      89a76aede314 7b3dda341c84 :   5441 revs,   1.666389 s,   0.056705 s,  -1.609684 s, × 0.0340,     10 µs/rev
pypy            x0000_revs_x_added_0_copies           d1defd0dc478 c9cb1334cc78 :  43646 revs,   0.001070 s,   0.794685 s,  +0.793615 s, × 742.69,     18 µs/rev
pypy            x0000_revs_xx000_added_0_copies       bf2c629d0071 4ffed77c095c :  26389 revs,   1.076269 s,   0.020209 s,  -1.056060 s, × 0.0187,      0 µs/rev
pypy            x0000_revs_xx000_added_x000_copies    08ea3258278e d9fa043f30c0 :  11316 revs,   1.355085 s,   0.122475 s,  -1.232610 s, × 0.0903,     10 µs/rev
netbeans        x_revs_x_added_0_copies               fb0955ffcbcd a01e9239f9e7 :      2 revs,   0.028551 s,   0.000142 s,  -0.028409 s, × 0.0049,     70 µs/rev
netbeans        x_revs_x000_added_0_copies            6f360122949f 20eb231cc7d0 :      2 revs,   0.157319 s,   0.000113 s,  -0.157206 s, × 0.0007,     56 µs/rev
netbeans        x_revs_x_added_x_copies               1ada3faf6fb6 5a39d12eecf4 :      3 revs,   0.025722 s,   0.000241 s,  -0.025481 s, × 0.0093,     80 µs/rev
netbeans        x_revs_x00_added_x_copies             35be93ba1e2c 9eec5e90c05f :      9 revs,   0.053374 s,   0.000729 s,  -0.052645 s, × 0.0136,     80 µs/rev
netbeans        x000_revs_xx00_added_0_copies         eac3045b4fdd 51d4ae7f1290 :   1421 revs,   0.038146 s,   0.010198 s,  -0.027948 s, × 0.2673,      7 µs/rev
netbeans        x000_revs_x000_added_x_copies         e2063d266acd 6081d72689dc :   1533 revs,   0.229215 s,   0.015312 s,  -0.213903 s, × 0.0668,      9 µs/rev
netbeans        x000_revs_x000_added_x000_copies      ff453e9fee32 411350406ec2 :   5750 revs,   0.974484 s,   0.060517 s,  -0.913967 s, × 0.0621,     10 µs/rev
netbeans        x0000_revs_xx000_added_x000_copies    588c2d1ced70 1aad62e59ddd :  67005 revs,   3.924308 s,   0.611102 s,  -3.313206 s, × 0.1557,      9 µs/rev
mozilla-central x_revs_x_added_0_copies               3697f962bb7b 7015fcdd43a2 :      2 revs,   0.035563 s,   0.000164 s,  -0.035399 s, × 0.0046,     81 µs/rev
mozilla-central x_revs_x000_added_0_copies            dd390860c6c9 40d0c5bed75d :      8 revs,   0.145766 s,   0.000334 s,  -0.145432 s, × 0.0022,     41 µs/rev
mozilla-central x_revs_x_added_x_copies               8d198483ae3b 14207ffc2b2f :      9 revs,   0.026283 s,   0.000463 s,  -0.025820 s, × 0.0176,     51 µs/rev
mozilla-central x_revs_x00_added_x_copies             98cbc58cc6bc 446a150332c3 :      7 revs,   0.087403 s,   0.000730 s,  -0.086673 s, × 0.0083,    104 µs/rev
mozilla-central x_revs_x000_added_x000_copies         3c684b4b8f68 0a5e72d1b479 :      3 revs,   0.209484 s,   0.003522 s,  -0.205962 s, × 0.0168,   1173 µs/rev
mozilla-central x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   2.197867 s,   0.072518 s,  -2.125349 s, × 0.0329,  12084 µs/rev
mozilla-central x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.090142 s,   0.005760 s,  -0.084382 s, × 0.0638,      3 µs/rev
mozilla-central x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :   8315 revs,   0.742658 s,   0.005720 s,  -0.736938 s, × 0.0077,      0 µs/rev
mozilla-central x000_revs_x000_added_x000_copies      7c97034feb78 4407bd0c6330 :   7839 revs,   1.166159 s,   0.063310 s,  -1.102849 s, × 0.0542,      8 µs/rev
mozilla-central x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :  45299 revs,   6.721719 s,   0.043608 s,  -6.678111 s, × 0.0064,      0 µs/rev
mozilla-central x0000_revs_xx000_added_x000_copies    f78c615a656c 96a38b690156 :  30263 revs,   3.356523 s,   0.204831 s,  -3.151692 s, × 0.0610,      6 µs/rev
mozilla-central x00000_revs_x0000_added_x0000_copies  6832ae71433c 4c222a1d9a00 : 153721 revs,  15.880822 s,   2.161906 s, -13.718916 s, × 0.1361,     14 µs/rev
mozilla-central x00000_revs_x00000_added_x000_copies  76caed42cf7c 1daa622bbe42 : 210546 revs,  20.781275 s,   3.291831 s, -17.489444 s, × 0.1584,     15 µs/rev
mozilla-try     x_revs_x_added_0_copies               aaf6dde0deb8 9790f499805a :      2 revs,   0.084165 s,   0.001213 s,  -0.082952 s, × 0.0144,    606 µs/rev
mozilla-try     x_revs_x000_added_0_copies            d8d0222927b4 5bb8ce8c7450 :      2 revs,   0.503744 s,   0.001225 s,  -0.502519 s, × 0.0024,    612 µs/rev
mozilla-try     x_revs_x_added_x_copies               092fcca11bdb 936255a0384a :      4 revs,   0.021545 s,   0.000564 s,  -0.020981 s, × 0.0261,    140 µs/rev
mozilla-try     x_revs_x00_added_x_copies             b53d2fadbdb5 017afae788ec :      2 revs,   0.240699 s,   0.001549 s,  -0.239150 s, × 0.0064,    774 µs/rev
mozilla-try     x_revs_x000_added_x000_copies         20408ad61ce5 6f0ee96e21ad :      1 revs,   1.100682 s,   0.035918 s,  -1.064764 s, × 0.0326,  35882 µs/rev
mozilla-try     x_revs_x0000_added_x0000_copies       effb563bb7e5 c07a39dc4e80 :      6 revs,   2.234809 s,   0.073788 s,  -2.161021 s, × 0.0330,  12295 µs/rev
mozilla-try     x000_revs_xx00_added_0_copies         6100d773079a 04a55431795e :   1593 revs,   0.091222 s,   0.006151 s,  -0.085071 s, × 0.0674,      3 µs/rev
mozilla-try     x000_revs_x000_added_x_copies         9f17a6fc04f9 2d37b966abed :   8315 revs,   0.764722 s,   0.006165 s,  -0.758557 s, × 0.0080,      0 µs/rev
mozilla-try     x000_revs_x000_added_x000_copies      1346fd0130e4 4c65cbdabc1f :   6657 revs,   1.185655 s,   0.065421 s,  -1.120234 s, × 0.0551,      9 µs/rev
mozilla-try     x0000_revs_x_added_0_copies           63519bfd42ee a36a2a865d92 :  40314 revs,   0.089736 s,   0.313749 s,  +0.224013 s, × 3.4963,      7 µs/rev
mozilla-try     x0000_revs_x_added_x_copies           9fe69ff0762d bcabf2a78927 :  38690 revs,   0.084132 s,   0.297867 s,  +0.213735 s, × 3.5404,      7 µs/rev
mozilla-try     x0000_revs_xx000_added_x_copies       156f6e2674f2 4d0f2c178e66 :  54487 revs,   7.581932 s,   0.111300 s,  -7.470632 s, × 0.0146,      2 µs/rev
mozilla-try     x0000_revs_xx000_added_0_copies       9eec5917337d 67118cc6dcad :  45299 revs,   6.671144 s,   0.046202 s,  -6.624942 s, × 0.0069,      1 µs/rev
mozilla-try     x0000_revs_xx000_added_x000_copies    89294cd501d9 7ccb2fc7ccb5 :  97052 revs,   7.674771 s,   1.999640 s,  -5.675131 s, × 0.2605,     20 µs/rev
mozilla-try     x0000_revs_x0000_added_x0000_copies   e928c65095ed e951f4ad123a :  52031 revs,   9.870343 s,   0.809134 s,  -9.061209 s, × 0.0819,     15 µs/rev
mozilla-try     x00000_revs_x_added_0_copies          6a320851d377 1ebb79acd503 : 363753 revs,   0.094781 s,  47.406785 s, +47.312004 s, × 500.17,    130 µs/rev
mozilla-try     x00000_revs_x00000_added_0_copies     dc8a3ca7010e d16fde900c9c : 444327 revs,  26.690029 s,   0.996219 s, -25.693810 s, × 0.0373,      2 µs/rev
mozilla-try     x00000_revs_x_added_x_copies          5173c4b6f97c 95d83ee7242d : 362229 revs,   0.094941 s,  47.273399 s, +47.178458 s, × 497.92,    130 µs/rev
mozilla-try     x00000_revs_x000_added_x_copies       9126823d0e9c ca82787bb23c : 359344 revs,   0.233811 s,  47.419099 s, +47.185288 s, × 202.80,    131 µs/rev
mozilla-try     x00000_revs_x0000_added_x0000_copies  8d3fafa80d4b eb884023b810 : 192665 revs,  19.321750 s,   3.512653 s, -15.809097 s, × 0.1817,     18 µs/rev
mozilla-try     x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 237259 revs,  21.358350 s,  44.459049 s, +23.100699 s, × 2.0815,    187 µs/rev
mozilla-try     x00000_revs_x00000_added_x000_copies  9b2a99adc05e 8e29777b48e6 : 391148 revs,  25.328737 s,  52.837926 s, +27.509189 s, × 2.0860,    135 µs/rev

Differential Revision: https://phab.mercurial-scm.org/D9307

  $ heads()
  > {
  >    hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@"
  > }

  $ hg init a
  $ cd a
  $ echo 'root' >root
  $ hg add root
  $ hg commit -m "Adding root node"
  $ heads
  0: Adding root node ()
-------
  $ heads .
  0: Adding root node ()

=======

  $ echo 'a' >a
  $ hg add a
  $ hg branch a
  marked working directory as branch a
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -m "Adding a branch"
  $ heads
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  1: Adding a branch (a)

=======

  $ hg update -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'b' >b
  $ hg add b
  $ hg branch b
  marked working directory as branch b
  $ hg commit -m "Adding b branch"
  $ heads
  2: Adding b branch (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  2: Adding b branch (b)

=======

  $ echo 'bh1' >bh1
  $ hg add bh1
  $ hg commit -m "Adding b branch head 1"
  $ heads
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  3: Adding b branch head 1 (b)

=======

  $ hg update -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'bh2' >bh2
  $ hg add bh2
  $ hg commit -m "Adding b branch head 2"
  created new head
  $ heads
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  $ heads .
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)

=======

  $ hg update -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'bh3' >bh3
  $ hg add bh3
  $ hg commit -m "Adding b branch head 3"
  created new head
  $ heads
  5: Adding b branch head 3 (b)
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  5: Adding b branch head 3 (b)
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)

=======

  $ hg merge 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m "Merging b branch head 2 and b branch head 3"
  $ heads
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)

=======

  $ echo 'c' >c
  $ hg add c
  $ hg branch c
  marked working directory as branch c
  $ hg commit -m "Adding c branch"
  $ heads
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  7: Adding c branch (c)

=======

  $ heads -r 3 .
  no open branch heads found on branches c (started at 3)
  [1]
  $ heads -r 2 .
  7: Adding c branch (c)
-------
  $ hg update -C 4
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
-------
  $ heads -r 3 .
  3: Adding b branch head 1 (b)
-------
  $ heads -r 2 .
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
-------
  $ heads -r 7 .
  no open branch heads found on branches b (started at 7)
  [1]

=======

  $ for i in 0 1 2 3 4 5 6 7; do
  >     hg update -C "$i"
  >     heads
  >     echo '-------'
  >     heads .
  >     echo '-------'
  > done
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  0: Adding root node ()
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  1: Adding a branch (a)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  7: Adding c branch (c)
  -------

=======

  $ for i in a b c z; do
  >     heads "$i"
  >     echo '-------'
  > done
  1: Adding a branch (a)
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  7: Adding c branch (c)
  -------
  abort: unknown revision 'z'
  -------

=======

  $ heads 0 1 2 3 4 5 6 7
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()

Topological heads:

  $ heads -t
  7: Adding c branch (c)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)

  $ cd ..
______________

"created new head" message tests

  $ hg init newheadmsg
  $ cd newheadmsg

Init: no msg

  $ echo 1 > a
  $ hg ci -Am "a0: Initial root"
  adding a
  $ echo 2 >> a
  $ hg ci -m "a1 (HN)"

  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ echo 1 > b
  $ hg ci -Am "b2: Initial root for branch b"
  adding b
  $ echo 2 >> b
  $ hg ci -m "b3 (HN)"

Case NN: msg

  $ hg up -q null
  $ hg branch -f b
  marked working directory as branch b
  $ echo 1 > bb
  $ hg ci -Am "b4 (NN): new topo root for branch b"
  adding bb
  created new head

Case HN: no msg

  $ echo 2 >> bb
  $ hg ci -m "b5 (HN)"

Case BN: msg

  $ hg branch -f default
  marked working directory as branch default
  $ echo 1 > aa
  $ hg ci -Am "a6 (BN): new branch root"
  adding aa
  created new head

Case CN: msg

  $ hg up -q 4
  $ echo 3 >> bbb
  $ hg ci -Am "b7 (CN): regular new head"
  adding bbb
  created new head

Case BB: msg

  $ hg up -q 4
  $ hg merge -q 3
  $ hg branch -f default
  marked working directory as branch default
  $ hg ci -m "a8 (BB): weird new branch root"
  created new head

Case CB: msg

  $ hg up -q 4
  $ hg merge -q 1
  $ hg ci -m "b9 (CB): new head from branch merge"
  created new head

Case HB: no msg

  $ hg up -q 7
  $ hg merge -q 6
  $ hg ci -m "b10 (HB): continuing head from branch merge"

Case CC: msg

  $ hg up -q 4
  $ hg merge -q 2
  $ hg ci -m "b11 (CC): new head from merge"
  created new head

Case CH: no msg

  $ hg up -q 2
  $ hg merge -q 10
  $ hg ci -m "b12 (CH): continuing head from merge"

Case HH: no msg

  $ hg merge -q 3
  $ hg ci -m "b12 (HH): merging two heads"

  $ cd ..