pull: hold wlock for the full operation when --update is used With now, the wlock is not held between the pull and the update. This can lead to race condition and make logic checking to post pull results more complicated (eg: with _afterlock).

hgweb: drop support of browsers that don't understand <canvas> (BC) Internet Explorer 8 and below need excanvas aka ExplorerCanvas to support canvas tag at all. We used to vendor the library in Mercurial, but IE8 was discontinued and all support for it ceased in January 2016. We should do the same and remove excanvas library. Apart from just cleaning up code, this will also make downstream Debian packages stop depending on libjs-excanvas, for example.

rust: add TODO about lifetime of program_name variable Per review comment in D1581. Differential Revision: https://phab.mercurial-scm.org/D1847

rust: move import of PathBuf By moving it to the single function that uses it, we eliminate a #cfg. Differential Revision: https://phab.mercurial-scm.org/D1845

perf: do not import util.queue This was added by af25237be091. But util.queue is not a module and is not importable. I guess it wasn't noticed because of demandimport. Differential Revision: https://phab.mercurial-scm.org/D1848

rust: move Cargo.lock If you do a `cargo build` in rust/, Cargo will create rust/Cargo.lock. Furthermore, the previous rust/hgcli/Cargo.lock appears to not even be consulted because the auto-generated rust/Cargo.lock varied from rust/hgcli/Cargo.lock. This commit moves Cargo.lock to where Cargo expects it to be. While we're here, bump the version of libc to the latest available. Differential Revision: https://phab.mercurial-scm.org/D1844

run-tests: fix regular expression for path test The previous regexp would match the empty string. This fixes a mistake added in 964212780daf. Differential Revision: https://phab.mercurial-scm.org/D1843

perf: add threading capability to perfbdiff Since we are releasing the GIL during diffing, it is interesting to see how a thread pool would perform on diffing. We add a new `--threads` argument to commands. Synchronizing the thread pool is a bit complex because we want to be able to reuse it from one run to another. On my computer (i7 with 4 cores + hyperthreading), I get the following data for about 12000 revisions: threads wall comb wall gain comb overhead none 31.596715 31.59 0.00% 0.00% 1 31.621228 31.62 -0.08% 0.09% 2 16.406202 32.8 48.08% 3.83% 3 11.598334 34.76 63.29% 10.03% 4 9.205421 36.77 70.87% 16.40% 5 8.517604 42.51 73.04% 34.57% 6 7.94645 47.58 74.85% 50.62% 7 7.434972 51.92 76.47% 64.36% 8 7.070638 55.34 77.62% 75.18% Compared to the feature disabled (threads=0), the overhead is negligible with the threading code (threads=1), and the gain is already 48% with two threads.

upgraderepo: select correct deltareuse depending on actions Only 'redeltafulladd' was taken into account because of a small typo.

revsetlang: add %p specifier to format list of function arguments This will be used to construct parameters passed to _matchfiles().