copies: extract data extraction into a `revinfo` function The function is build once at the beginning of the algorithm and used fetch appropriate information for each revision. This abstracts some implementation details from the main algorithm and will help us to access the data more efficiently in future changesets. Differential Revision: https://phab.mercurial-scm.org/D7070

copies: avoid instancing more changectx to access parent revisions We just need to know the revision numbers of the parents, creating full context is needlessly expensive. This provide a small, but noticeable performance boost. revision: large amount; added files: large amount; rename small amount; c3b14617fbd7 9ba6ab77fd29 before: ! wall 2.885636 comb 2.900000 user 2.870000 sys 0.030000 (median of 10) after: ! wall 2.702270 comb 2.710000 user 2.690000 sys 0.020000 (median of 10) revision: large amount; added files: small amount; rename small amount; c3b14617fbd7 f650a9b140d2 before: ! wall 4.298271 comb 4.290000 user 4.240000 sys 0.050000 (median of 10) after: ! wall 3.976610 comb 3.970000 user 3.920000 sys 0.050000 (median of 10) revision: large amount; added files: large amount; rename large amount; 08ea3258278e d9fa043f30c0 before: ! wall 0.773397 comb 0.770000 user 0.770000 sys 0.000000 (median of 11) after: ! wall 0.701634 comb 0.700000 user 0.700000 sys 0.000000 (median of 13) revision: small amount; added files: large amount; rename large amount; df6f7a526b60 a83dc6a2d56f before: ! wall 0.013585 comb 0.010000 user 0.010000 sys 0.000000 (median of 217) after: ! wall 0.013550 comb 0.010000 user 0.010000 sys 0.000000 (median of 218) revision: small amount; added files: large amount; rename small amount; 4aa4e1f8e19a 169138063d63 before: ! wall 0.003202 comb 0.000000 user 0.000000 sys 0.000000 (median of 929) after: ! wall 0.002993 comb 0.010000 user 0.010000 sys 0.000000 (median of 992) revision: small amount; added files: small amount; rename small amount; 4bc173b045a6 964879152e2e before: ! wall 0.000077 comb 0.000000 user 0.000000 sys 0.000000 (median of 12060) after: ! wall 0.000072 comb 0.000000 user 0.000000 sys 0.000000 (median of 12804) revision: medium amount; added files: large amount; rename medium amount; c95f1ced15f2 2c68e87c3efe before: ! wall 0.510614 comb 0.500000 user 0.500000 sys 0.000000 (median of 18) after: ! wall 0.473681 comb 0.470000 user 0.470000 sys 0.000000 (median of 20) revision: medium amount; added files: medium amount; rename small amount; d343da0c55a8 d7746d32bf9d before: ! wall 0.126552 comb 0.130000 user 0.130000 sys 0.000000 (median of 77) after: ! wall 0.115240 comb 0.110000 user 0.110000 sys 0.000000 (median of 85) Differential Revision: https://phab.mercurial-scm.org/D7122

copies: get copies information directly from _copies Performance measurement does not show any significant performance movement. This is not surprising since p1copies() code is `self._copies[0]`. Differential Revision: https://phab.mercurial-scm.org/D7121

copies: simplify the handling of merges Instead of stacking copies for both parent on the head, we move copies outside of the heap into a dedicated dictionary. The two side of merge can we merged sooner, making the algorithm simpler. This simplicity reflect in the heap structure and speed up the execution for copies involving a large amount of merges. Here are timing for perfpathcopies of multiple revision pairs. - filelog: timing using filelog (with the introrev condition dropped) - base: this series base - before: the parent of this changeset - after: this changeset revision: large amount; added files: large amount; rename small amount; c3b14617fbd7 9ba6ab77fd29 filelog: ! wall 3.679613 comb 3.680000 user 3.580000 sys 0.100000 (median of 3) base: ! wall 8.884369 comb 8.880000 user 8.850000 sys 0.030000 (median of 3) before: ! wall 8.443747 comb 8.420000 user 8.410000 sys 0.010000 (median of 3) after: ! wall 4.697917 comb 4.690000 user 4.660000 sys 0.030000 (median of 3) revision: large amount; added files: small amount; rename small amount; c3b14617fbd7 f650a9b140d2 filelog: ! wall 0.003357 comb 0.010000 user 0.010000 sys 0.000000 (median of 781) base: ! wall 12.398524 comb 12.400000 user 12.330000 sys 0.070000 (median of 3) before: ! wall 10.852593 comb 10.850000 user 10.800000 sys 0.050000 (median of 3) after: ! wall 6.750832 comb 6.750000 user 6.640000 sys 0.110000 (median of 3) revision: large amount; added files: large amount; rename large amount; 08ea3258278e d9fa043f30c0 filelog: ! wall 2.754687 comb 2.760000 user 2.650000 sys 0.110000 (median of 4) base: ! wall 1.423166 comb 1.420000 user 1.400000 sys 0.020000 (median of 8) before: ! wall 1.068041 comb 1.060000 user 1.050000 sys 0.010000 (median of 10) after: ! wall 1.045916 comb 1.050000 user 1.040000 sys 0.010000 (median of 10) revision: small amount; added files: large amount; rename large amount; df6f7a526b60 a83dc6a2d56f filelog: ! wall 1.552293 comb 1.550000 user 1.510000 sys 0.040000 (median of 6 base: ! wall 0.022662 comb 0.020000 user 0.020000 sys 0.000000 (median of 128) before: ! wall 0.021111 comb 0.020000 user 0.020000 sys 0.000000 (median of 139) after: ! wall 0.021577 comb 0.020000 user 0.020000 sys 0.000000 (median of 138) revision: small amount; added files: large amount; rename small amount; 4aa4e1f8e19a 169138063d63 filelog: ! wall 1.500983 comb 1.500000 user 1.420000 sys 0.080000 (median of 7) base: ! wall 0.006956 comb 0.010000 user 0.010000 sys 0.000000 (median of 392) before: ! wall 0.004356 comb 0.010000 user 0.010000 sys 0.000000 (median of 675) after: ! wall 0.004329 comb 0.000000 user 0.000000 sys 0.000000 (median of 682) revision: small amount; added files: small amount; rename small amount; 4bc173b045a6 964879152e2e filelog: ! wall 0.011745 comb 0.020000 user 0.020000 sys 0.000000 (median of 250) base: ! wall 0.000156 comb 0.000000 user 0.000000 sys 0.000000 (median of 17180) before: ! wall 0.000100 comb 0.000000 user 0.000000 sys 0.000000 (median of 26912) after: ! wall 0.000105 comb 0.000000 user 0.000000 sys 0.000000 (median of 25689) revision: medium amount; added files: large amount; rename medium amount; c95f1ced15f2 2c68e87c3efe filelog: ! wall 3.228230 comb 3.230000 user 3.110000 sys 0.120000 (median of 4) base: ! wall 0.997640 comb 1.000000 user 0.980000 sys 0.020000 (median of 10) before: ! wall 0.778291 comb 0.780000 user 0.780000 sys 0.000000 (median of 13) after: ! wall 0.706594 comb 0.710000 user 0.710000 sys 0.000000 (median of 15) revision: medium amount; added files: medium amount; rename small amount; d343da0c55a8 d7746d32bf9d filelog: ! wall 1.052501 comb 1.060000 user 1.040000 sys 0.020000 (median of 10 base: ! wall 0.214519 comb 0.220000 user 0.220000 sys 0.000000 (median of 45) before: ! wall 0.160804 comb 0.160000 user 0.160000 sys 0.000000 (median of 62) after: ! wall 0.163736 comb 0.160000 user 0.160000 sys 0.000000 (median of 60) Differential Revision: https://phab.mercurial-scm.org/D7069

rust-utils: introduce a debug util to print the python stack trace Differential Revision: https://phab.mercurial-scm.org/D7057

rust-cross-platform: remove `unimplemented!` to get compile-time errors We should get a compile-time error that there is missing functionality for the targeted platform instead of the program breaking at runtime. Differential Revision: https://phab.mercurial-scm.org/D7107