emitrevision: consider ancestors revision to emit as available base This should make more delta base valid. This notably affects: * case where we skipped some parent with empty delta to directly delta against an ancestors * case where an intermediate snapshots is stored. This change means we could sent largish intermediate snapshots over the wire. However this is actually a sub goal here. Sending snapshots over the wire means the client have a high odd of simply storing the pre-computed delta instead of doing a lengthy process that will… end up doing the same intermediate snapshot. In addition the overall size of snapshot (or any level) is "only" some or the overall delta size. (0.17% for my mercurial clone, 20% for my clone of Mozilla try). So Sending them other the wire is unlikely to change large impact on the bandwidth used. If we decide that minimising the bandwidth is an explicit goal, we should introduce new logic to filter-out snapshot as delta. The current code has no notion explicite of snapshot so far, they just tended to fall into the wobbly filtering options. In some cases, this patch can yield large improvement to the bundling time: ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = perf-bundle # benchmark.variants.revs = last-100000 before: 68.787066 seconds after: 47.552677 seconds (-30.87%) That translate to large improvement to the pull time : ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = pull # benchmark.variants.issue6528 = disabled # benchmark.variants.revs = last-100000 before: 142.186625 seconds after: 75.897745 seconds (-46.62%) No significant negative impact have been observed.

sqlitestore: add an `ancestors` method We will need it during bundling. The implementation mirror the one in revlog.

emitrevision: if we need to compute a delta on the fly, try p1 or p2 first Falling back to `prev` does not yield any real value on modern storage and result in pathological changes to be created on the other side. Doing a delta against a parent will likely be smaller (helping the network) and will be safer to apply on the client (helping future pulls by Triggering intermediate snapshop where they will be needed by later deltas).

emitrevision: simplify the fallback to computed delta Not using the stored delta, or having a full snapshot on disk behave the same ways, so lets use the same code path for that, this is simpler, and it update will be simpler.

emitrevision: also check the parents in the availability closure One of the point of having a closure is to gather the logic in it. So we gather the logic. The `parents[:]` part is a bit ugly but will be replaced by better code soon anyway.

emitrevision: add a small closure to check if a base is usable We will make more use of this and make it more complex too.

reuse-delta-base: improves some documentation The current code got me a bit confused initially. So a bit more documentation around it cannot hurt.

tests: expect the message from 1baf0fffd82f in test-hghave.t (issue6762) Couldn't reproduce locally, but apparently this message may occasionally pop up when running this test.

branching: merge stable into default

changelog-v2: add a configuration to disable rank computation We encountered a graph where rank computation was pathologically slow. We add an option to disable this computation while this is getting fixed. Disabling the rank computation should allow for testing other changelog-v2 features undisturbed (like changeset-based copy tracing). I am purposely not adding a test for the new non-default code path, as this is a temporary work around of an experimental feature.

debugrevlog: display total stored information This is an interesting statistis, so let's display it.

debug-revlog: details about non-ancestors delta-bases Deltas against a base that is not an ancestor of the revision that owns this delta are notable. For example, they introduce complexity during the bundling process as the base might not exist on the unbundling side. We detect them in `hg debugrevlog` and print information about them.

debug-revlog: move the code in revlogutils module We have a module dedicated to debug code, let us use it.

debug-revlog: move the --dump code in `revlogutils` module We have a module dedicated to debug code, let us use it.

delta-find: set the default candidate chunk size to 10 I ran performance and storage tests on repositories of various sizes and shapes for the following values of the config : 5, 10, 20, 50, 100, no-chunking The performance tests do not show any statistical impact on computation times for large pushes and pulls. For searching for an individual delta, this can provide a significant performance improvement with a minor degradation of space-quality on the result. (see data at the end of the commit). For overall store size, the change : - does not have any impact on many small repositories, - has an observable, but very negligible impact on most larger repositories. - One private repository we use for testing sees a small increase in size (1%) in the narrower version. We will try to get more numbers on a larger version of that repository to make sure nothing pathological happens. We pick "10" as the limit as "5" seems a bit more risky. There are room to improve the current code, by using more aggressive filtering and better (i.e any) sorting of the candidates. However this is already a large improvement for pathological cases, with little impact in the common situations. The initial motivation for this change is to fix performance of delta computation for a file where the previous code ended up testing 20 000 possible candidate-bases in one go, which is… slow. This affected about ½ of the file revisions leading to atrocious performance, especially during some push/pull operations. Details about individual delta finding timing: ---------------------------------------------- The vast majority of benchmark cases are unchanged but the three below. The first two do not see any impact on the final delta. The last one sees a change in delta-size that is negligible compared to the full text size. ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = perf-delta-find # benchmark.variants.rev = manifest-snapshot-many-tries-a (revision 756096) ∞: 5.844783 5: 4.473523 (-23.46%) 10: 4.970053 (-14.97%) 20: 5.770386 (-1.27%) 50 5.821358 100: 5.834887 MANIFESTLOG: rev = 756096: (no-limit) delta-base = 301840 search-rounds = 6 try-count = 60 delta-type = snapshot snap-depth = 7 delta-size = 179 MANIFESTLOG: rev=756096: (limit = 10) delta-base=301840 search-rounds=9 try-count=51 delta-type=snapshot snap-depth=7 delta-size=179 ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = perf-delta-find # benchmark.variants.rev = manifest-snapshot-many-tries-d (revision 754060) ∞: 5.017663 5: 3.655931 (-27.14%) 10: 4.095436 (-18.38%) 20: 4.828949 (-3.76%) 50 4.987574 100: 4.994889 MANIFESTLOG: rev=754060: (no limit) delta-base=301840 search-rounds=5 try-count=53 delta-type=snapshot snap-depth=7 delta-size = 179 MANIFESTLOG: rev=754060: (limite = 10) delta-base=301840 search-rounds=8 try-count=45 delta-type=snapshot snap-depth=7 delta-size = 179 ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = perf-delta-find # bin-env-vars.hg.flavor = rust # benchmark.variants.rev = manifest-snapshot-many-tries-e (revision 693368) ∞: 4.869282 5: 2.039732 (-58.11%) 10: 2.413537 (-50.43%) 20: 4.449639 (-8.62%) 50 4.865863 100: 4.882649 MANIFESTLOG: rev=693368: delta-base=693336 search-rounds=6 try-count=53 delta-type=snapshot snap-depth=6 full-test-size=131065 delta-size=199 MANIFESTLOG: rev=693368: delta-base=278023 search-rounds=5 try-count=21 delta-type=snapshot snap-depth=4 full-test-size=131065 delta-size=278 Raw data for store size (in bytes) for various chunk size value below: ---------------------------------------------------------------------- 440 134 384 5 pypy/.hg/store/ 440 134 384 10 pypy/.hg/store/ 440 134 384 20 pypy/.hg/store/ 440 134 384 50 pypy/.hg/store/ 440 134 384 100 pypy/.hg/store/ 440 134 384 ... pypy/.hg/store/ 666 987 471 5 netbsd-xsrc-2022-11-15/.hg/store/ 666 987 471 10 netbsd-xsrc-2022-11-15/.hg/store/ 666 987 471 20 netbsd-xsrc-2022-11-15/.hg/store/ 666 987 471 50 netbsd-xsrc-2022-11-15/.hg/store/ 666 987 471 100 netbsd-xsrc-2022-11-15/.hg/store/ 666 987 471 ... netbsd-xsrc-2022-11-15/.hg/store/ 852 844 884 5 netbsd-pkgsrc-2022-11-15/.hg/store/ 852 844 884 10 netbsd-pkgsrc-2022-11-15/.hg/store/ 852 844 884 20 netbsd-pkgsrc-2022-11-15/.hg/store/ 852 844 884 50 netbsd-pkgsrc-2022-11-15/.hg/store/ 852 844 884 100 netbsd-pkgsrc-2022-11-15/.hg/store/ 852 844 884 ... netbsd-pkgsrc-2022-11-15/.hg/store/ 1 504 227 981 5 netbeans-2018-08-01-sparse-zstd/.hg/store/ 1 504 227 871 10 netbeans-2018-08-01-sparse-zstd/.hg/store/ 1 504 227 813 20 netbeans-2018-08-01-sparse-zstd/.hg/store/ 1 504 227 813 50 netbeans-2018-08-01-sparse-zstd/.hg/store/ 1 504 227 813 100 netbeans-2018-08-01-sparse-zstd/.hg/store/ 1 504 227 813 ... netbeans-2018-08-01-sparse-zstd/.hg/store/ 3 875 801 068 5 netbsd-src-2022-11-15/.hg/store/ 3 875 696 767 10 netbsd-src-2022-11-15/.hg/store/ 3 875 696 757 20 netbsd-src-2022-11-15/.hg/store/ 3 875 696 653 50 netbsd-src-2022-11-15/.hg/store/ 3 875 696 653 100 netbsd-src-2022-11-15/.hg/store/ 3 875 696 653 ... netbsd-src-2022-11-15/.hg/store/ 4 531 441 314 5 mozilla-central/.hg/store/ 4 531 435 157 10 mozilla-central/.hg/store/ 4 531 432 045 20 mozilla-central/.hg/store/ 4 531 429 119 50 mozilla-central/.hg/store/ 4 531 429 119 100 mozilla-central/.hg/store/ 4 531 429 119 ... mozilla-central/.hg/store/ 4 875 861 390 5 mozilla-unified/.hg/store/ 4 875 855 155 10 mozilla-unified/.hg/store/ 4 875 852 027 20 mozilla-unified/.hg/store/ 4 875 848 851 50 mozilla-unified/.hg/store/ 4 875 848 851 100 mozilla-unified/.hg/store/ 4 875 848 851 ... mozilla-unified/.hg/store/ 11 498 764 601 5 mozilla-try/.hg/store/ 11 497 968 858 10 mozilla-try/.hg/store/ 11 497 958 730 20 mozilla-try/.hg/store/ 11 497 927 156 50 mozilla-try/.hg/store/ 11 497 925 963 100 mozilla-try/.hg/store/ 11 497 923 428 ... mozilla-try/.hg/store/ 10 047 914 031 5 private-repo 9 969 132 101 10 private-repo 9 944 745 015 20 private-repo 9 939 756 703 50 private-repo 9 939 833 016 100 private-repo 9 939 822 035 ... private-repo

delta-find: add a way to control the number of bases tested at the same time See inline comment for details. The feature is currently disabled, but should be enabled by default to mitigate some existing pathological cases. Also see the next changeset for details.

test: adjust test-push-race.t timeout's to overall test timeout The generic `tests/testlib/wait-on-file` mechanism scale its timeout with the value of `HGTEST_TIMEOUT`, the `delaypush.py` in `test-push-race.t` is not doing this, and we have been seeing more and more timeout from loaded CI worker lately. Adding this timeout scaling should help with that.

setup: include vendored 3rd party type stubs While pytype may not support PEP 561, PyCharm does, so having the stubs available means it can determine `foo = attr.ib(type=int)` means `foo` is an int. This only applies when using Mercurial as a library, like with TortoiseHg development- PyCharm is already smart enough to use the *.pyi files in the Mercurial source tree when hacking on Mercurial itself. I left the mercurial.cext stubs out because it seems very low level, that 3rd parties shouldn't be using directly.

ci: bump pytype to 2022.11.18 No particular reason, other than the current build is fairly old. It flagged a few more things (that weren't errors based on the logic around them), but OTOH, some of the pyi stubs it generates are less specific.

ci: run the script to add vendored type stubs to typeshed Since CI runs from docker images, it doesn't matter that this mucks with the typeshed bundled with pytype.

contrib: add a script for adding vendored type stubs to typeshed I really hate this, but pytype doesn't support PEP 561 and doesn't seem to have the equivalent of `MYPYPATH` to point to custom stubs. Ignoring the vendored stubs isn't necessarily harmful, but pytype has been choking on the vendored attr package after pytype 2022.03.29 with errors like this: File "/mnt/c/Users/Matt/hg/mercurial/linelog.py", line 52, in __iter__: Built-in function iter was called with the wrong arguments [wrong-arg-types] Expected: (collection: bytearray) Actually passed: (collection: mercurial.thirdparty.attr._make._CountingAttr) File "/mnt/c/Users/Matt/hg/mercurial/dirstateutils/v2.py", line 143, in pack: Built-in function len was called with the wrong arguments [wrong-arg-types] Expected: (obj: Sized) Actually passed: (obj: mercurial.thirdparty.attr._make._CountingAttr) Attributes of protocol Sized are not implemented on mercurial.thirdparty.attr._make._CountingAttr: __len__ File "/mnt/c/Users/Matt/hg/mercurial/dirstateutils/v2.py", line 144, in pack: No attribute 'rfind' on mercurial.thirdparty.attr._make._CountingAttr [attribute-error] File "/mnt/c/Users/Matt/hg/mercurial/dirstateutils/v2.py", line 146, in pack: Built-in function len was called with the wrong arguments [wrong-arg-types] Expected: (obj: Sized) Actually passed: (obj: mercurial.thirdparty.attr._make._CountingAttr) Attributes of protocol Sized are not implemented on mercurial.thirdparty.attr._make._CountingAttr: __len__ File "/mnt/c/Users/Matt/hg/mercurial/dirstateutils/v2.py", line 152, in pack: No attribute 'v2_data' on mercurial.thirdparty.attr._make._CountingAttr [attribute-error] File "/mnt/c/Users/Matt/hg/mercurial/util.py", line 2817, in go: unsupported operand type(s) for /: 'count: mercurial.thirdparty.attr._make._CountingAttr' and 'float: float' [unsupported-operands] No attribute '__truediv__' on 'count: mercurial.thirdparty.attr._make._CountingAttr' or '__rtruediv__' on 'float: float' Called from (traceback): line 2981, in __bytes__ This is essentially the same hack we've been using in TortoiseHg to add the vendored PyQt5 stubs. What I don't understand is pytype *still* generates *.pyi files under .pytype/pyi/mercurial/thirdparty/attr, even when the package is explicitly ignored in the pytype command line args. But it avoids the errors, which means we aren't stuck on pytype==2022.03.29. https://github.com/google/pytype/issues/151

contrib: update check-pytype.sh to list stubs that caused pytype to crash The same logic is in the TortoiseHg tests for running pytype, and it's useful to know if a new version of pytype is better or worse.

typing: add py.typed to mercurial.cext for PEP 561 support Unfortunately, pytype doesn't support this yet. But it was included with the attr package, so we might as well do it here for consistency. Unlike the attr package, these type hints are only partial, so they are marked as such[1] (but who knows if it matters, given these are C extensions, so no local source code to scan). [1] https://peps.python.org/pep-0561/#partial-stub-packages

typing: add missing signature for mercurial.cext.parsers.parse_index2() Flagged by pytype 2022.11.18 when the cext stubs are made visible to it. There are very likely other signatures that are missing, but this is enough to keep it happy for now.

typing: minor tweaks to allow updating to pytype 2022.11.18

python-compat: adapt to Python 3.11 BC breakage with `random.sample` As per https://docs.python.org/3/whatsnew/3.11.html#porting-to-python-3-11: "The population parameter of `random.sample()` must be a sequence, and automatic conversion of sets to lists is no longer supported. Also, if the sample size is larger than the population size, a `ValueError` is raised"

typing: add type hints to mercurial/help.py Was hoping to find more issues like f09bc2ed9100, but it may be that nothing checks the args to that operation. In any event, the work is done and pytype doesn't do a very good job inferring the types. A few of th emore complicated things like the command table are left untyped, because they come from modules that aren't typed yet.

match: make the FLAG_RE pattern a raw string PyCharm was complaining about invalid escape sequences since this was added recently in 3eda36e9b3d6.

configitems: add a default value for "merge-tools.xxx.regappend" When trying to figure out how `hg help -v` took the Set interpolation path in f09bc2ed9100, I turned on devel warnings and noticed this (unrelated) warning: devel-warn: specifying a mismatched default value for a registered config item: 'merge-tools.beyondcompare4.regappend' '' at: c:\Users\Matt\hg\mercurial\filemerge.py:46 (_toolstr) The previous default value for this config was `None`, but that slightly complicates the code at the only site it is used, referenced above.

attr: vendor 22.1.0 The previous version was 5 years old, and pytype 2022.06.30 started complaining about various uses (e.g. seeing `mercurial.thirdparty.attr._make._CountingAttr` instead of `bytearray`). Hopefully this helps. Additionally, this has official python 3.11 support. The `attrs` package is left out, because it is simply a bunch of *.pyi stubs and `from attr.X import *`, and that's not how they've been used up to this point. We'd probably need to customize those anyway to `from mercurial.thirdparty.attr import *`.