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.

chg: scale the timeout in test with the rest This should avoid some flakiness where the logs reports server shutting down.

hghave: we might need py310 and py311 at some point Some tests are already showing slightly different results on Python 3.11. The better idea would be to make them more portable, but if that's not possible, now we can use hghave detection for certain lines. I wonder if there will ever be Python 31.0 and 31.1 though.

hghave: detect Python 3.10 and 3.11 as well Noticed because test-contrib-relnotes.t was skipped.

extensions: load help from hgext.__index__ as a fallback this time Prior to 843418dc0b1b, `hgext.__index__` was consulted first if present, which caused the longer help from the extension modules to be ignored, even when available. But that change causes a bunch of test failures when the pyoxidized binary bundles *.pyc in the binary, saying the there's no help topic for `hg help $disabled_extension` and suggesting the use of `--keyword`, rather than showing a summary and indicating that it is disabled. Current failures were in test-check-help.t, test-extension.t, test-help.t, and test-qrecord.t. Ideally, we would read the various *.pyc files from memory and slurp in the docstring, but I know that they used to not be readable as resources, and I can't figure out how to make it work now. So maybe 3.9 and/or the current PyOxidizer doesn't support it yet. I got closer in py2exe with `importlib.resources.open_binary("hgext", "rebase.pyc")`, but `open_binary()` on *.pyc fails in pyoxidizer.[1] Either way, the *.pyc can't be passed to `ast.parse()` as `extensions._disabledcmdtable()` is doing, so I'm setting that aside for now. [1] https://github.com/indygreg/PyOxidizer/issues/649

extensions: process disabled external paths when `hgext` package is in-memory This fixes `hg help -e ambiguous` in test-helpt.t:2055 with the `ambiguous = !./ambiguous.py` configuration, when `hgext` is not in the filesystem (e.g. pyoxidizer builds with in-memory resources, or TortoiseHg with py2exe), but the disabled external extension is. Now instead of aborting with a suggestion to try `--keyword`, the help command prints text for the extension.

hg: show the correct message when cloning an LFS repo with extension disabled The `extensions._disabledpaths()` doesn't handle fetching help from `__index__`, so it returns an empty dictionary of paths. That means None is always returned from `extensions.disabled_help()` when embedding resources inside the pyoxidizer or py2exe binary, regardless of the arg or if is an external extension stored in the filesystem. And that means wrongly telling the user with an explicitly disabled LFS extension that it will be enabled locally upon cloning from an LFS remote. That causes test-lfs-serve.t:295 to fail. This effectively reverts most of the rest of 843418dc0b1b, while keeping the help text change in place (which was specifically identified as a problem).

demandimport: fix a crash in LazyFinder.__delattr__ I was tinkering with `with hgdemandimport.deactivated()` wrapped around loading the keyring module, and got spew that seemed to be confirmed by PyCharm. But I can't believe we haven't seen this before (and phabricator uses the same pattern): ** Unknown exception encountered with possibly-broken third-party extension "mercurial_keyring" 1.4.3 (keyring 23.11.0, backend unknown) ** which supports versions unknown of Mercurial. ** Please disable "mercurial_keyring" and try your action again. ** If that fixes the bug please report it to https://foss.heptapod.net/mercurial/mercurial_keyring/issues ** Python 3.9.15 (main, Oct 13 2022, 04:28:25) [GCC 7.5.0] ** Mercurial Distributed SCM (version 6.3.1) ** Extensions loaded: absorb, attorc 20220315, blackbox, eol, extdiff, fastannotate, lfs, mercurial_keyring 1.4.3 (keyring 23.11.0, backend unknown), phabblocker 20220315, phabricator 20220315, purge, rebase, schemes, share, show, strip, uncommit Traceback (most recent call last): File "/usr/local/bin/hg", line 59, in <module> dispatch.run() File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 143, in run status = dispatch(req) File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 232, in dispatch status = _rundispatch(req) File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 276, in _rundispatch ret = _runcatch(req) or 0 File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 451, in _runcatch return _callcatch(ui, _runcatchfunc) File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 461, in _callcatch return scmutil.callcatch(ui, func) File "/usr/local/lib/python3.9/site-packages/mercurial/scmutil.py", line 153, in callcatch return func() File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 441, in _runcatchfunc return _dispatch(req) File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 1265, in _dispatch return runcommand( File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 899, in runcommand ret = _runcommand(ui, options, cmd, d) File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 1277, in _runcommand return cmdfunc() File "/usr/local/lib/python3.9/site-packages/mercurial/dispatch.py", line 1263, in <lambda> d = lambda: util.checksignature(func)(ui, *args, **strcmdopt) File "/usr/local/lib/python3.9/site-packages/mercurial/util.py", line 1880, in check return func(*args, **kwargs) File "/root/mercurial_keyring/mercurial_keyring/mercurial_keyring.py", line 962, in cmd_keyring_check user, pwd, source, final_url = handler.get_credentials( File "/root/mercurial_keyring/mercurial_keyring/mercurial_keyring.py", line 497, in get_credentials keyring_pwd = password_store.get_http_password(keyring_url, actual_user) File "/root/mercurial_keyring/mercurial_keyring/mercurial_keyring.py", line 287, in get_http_password return self._read_password_from_keyring( File "/root/mercurial_keyring/mercurial_keyring/mercurial_keyring.py", line 335, in _read_password_from_keyring keyring = import_keyring() >> `with hgdemandimport.deactivated()` inserted here File "/root/mercurial_keyring/mercurial_keyring/mercurial_keyring.py", line 120, in import_keyring return _import_keyring() File "/root/mercurial_keyring/mercurial_keyring/mercurial_keyring.py", line 133, in _import_keyring mod, was_imported_now = meu.direct_import_ext( File "/usr/lib/python3.9/site-packages/mercurial_extension_utils.py", line 1381, in direct_import_ext __import__(module_name) File "<frozen importlib._bootstrap>", line 1007, in _find_and_load File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 680, in _load_unlocked File "/usr/local/lib/python3.9/site-packages/hgdemandimport/demandimportpy3.py", line 46, in exec_module self.loader.exec_module(module) File "/usr/lib/python3.9/site-packages/keyring/__init__.py", line 1, in <module> from .core import ( File "<frozen importlib._bootstrap>", line 1007, in _find_and_load File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 680, in _load_unlocked File "/usr/local/lib/python3.9/site-packages/hgdemandimport/demandimportpy3.py", line 46, in exec_module self.loader.exec_module(module) File "/usr/lib/python3.9/site-packages/keyring/core.py", line 11, in <module> from . import backend, credentials File "<frozen importlib._bootstrap>", line 1007, in _find_and_load File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 680, in _load_unlocked File "/usr/local/lib/python3.9/site-packages/hgdemandimport/demandimportpy3.py", line 46, in exec_module self.loader.exec_module(module) File "/usr/lib/python3.9/site-packages/keyring/backend.py", line 13, in <module> from .py312compat import metadata File "<frozen importlib._bootstrap>", line 1007, in _find_and_load File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 680, in _load_unlocked File "/usr/local/lib/python3.9/site-packages/hgdemandimport/demandimportpy3.py", line 46, in exec_module self.loader.exec_module(module) File "/usr/lib/python3.9/site-packages/keyring/py312compat.py", line 10, in <module> import importlib_metadata as metadata # type: ignore File "<frozen importlib._bootstrap>", line 1007, in _find_and_load File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 680, in _load_unlocked File "/usr/local/lib/python3.9/site-packages/hgdemandimport/demandimportpy3.py", line 46, in exec_module self.loader.exec_module(module) File "/usr/lib/python3.9/site-packages/importlib_metadata/__init__.py", line 715, in <module> class MetadataPathFinder(NullFinder, DistributionFinder): File "/usr/lib/python3.9/site-packages/importlib_metadata/_compat.py", line 24, in install disable_stdlib_finder() File "/usr/lib/python3.9/site-packages/importlib_metadata/_compat.py", line 43, in disable_stdlib_finder del finder.find_distributions File "/usr/local/lib/python3.9/site-packages/hgdemandimport/demandimportpy3.py", line 88, in __delattr__ return delattr(object.__getattribute__(self, "_finder")) TypeError: delattr expected 2 arguments, got 1

bundle: emit full snapshot as is, without doing a redelta With the new `forced` delta-reused policy, it become important to be able to send full snapshot where full snapshot are needed. Otherwise, the fallback delta will simply be used on the client side… creating monstrous delta chain, since revision that are meant as a reset of delta-chain chain becoming too complex are simply adding a new full delta-tree on the leaf of another one. In the `non-forced` cases, client process full snapshot from the bundle differently from deltas, so client will still try to convert the full snapshot into a delta if possible. So this will no lead to pathological storage explosion. I have considered making this configurable, but the impact seems limited enough that it does not seems to be worth it. Especially with the current sparse-revlog format that use "delta-tree" with multiple level snapshots, full snapshot are much less frequent and not that different from other intermediate snapshot that we are already sending over the wire anyway. CPU wise, this will help the bundling side a little as it will not need to reconstruct revisions and compute deltas. The unbundling side might save a tiny amount of CPU as it won't need to reconstruct the delta-base to reconstruct the revision full text. This only slightly visible in some of the benchmarks. And have no real impact on most of them. ### data-env-vars.name = pypy-2018-08-01-zstd-sparse-revlog # benchmark.name = perf-bundle # benchmark.variants.revs = last-40000 before: 11.467186 seconds just-emit-full: 11.190576 seconds (-2.41%) with-pull-force: 11.041091 seconds (-3.72%) # benchmark.name = perf-unbundle # benchmark.variants.revs = last-40000 before: 16.744862 just-emit-full:: 16.561036 seconds (-1.10%) with-pull-force: 16.389344 seconds (-2.12%) # benchmark.name = pull # benchmark.variants.revs = last-40000 before: 26.870569 just-emit-full: 26.391188 seconds (-1.78%) with-pull-force: 25.633184 seconds (-4.60%) Space wise (so network-wise) the impact is fairly small. When taking compression into account. Below are tests the size of `hg bundle --all` for a handful of benchmark repositories (with bzip, zstd compression and without it) This show a small increase in the bundle size, but nothing really significant except maybe for mozilla-try (+12%) that nobody really pulls large chunk of anyway. Mozilla-try is also the repository that benefit the most for not having to recompute deltas client size. ### mercurial: bzip-before: 26 406 342 bytes bzip-after: 26 691 543 bytes +1.08% zstd-before: 27 918 645 bytes zstd-after: 28 075 896 bytes +0.56% none-before: 98 675 601 bytes none-after: 100 411 237 bytes +1.76% ### pypy bzip-before: 201 295 752 bytes bzip-after: 209 780 282 bytes +4.21% zstd-before: 202 974 795 bytes zstd-after: 205 165 780 bytes +1.08% none-before: 871 070 261 bytes none-after: 993 595 057 bytes +14.07% ### netbeans bzip-before: 601 314 330 bytes bzip-after: 614 246 241 bytes +2.15% zstd-before: 604 745 136 bytes zstd-after: 615 497 705 bytes +1.78% none-before: 3 338 238 571 bytes none-after: 3 439 422 535 bytes +3.03% ### mozilla-central bzip-before: 1 493 006 921 bytes bzip-after: 1 549 650 570 bytes +3.79% zstd-before: 1 481 910 102 bytes zstd-after: 1 513 052 415 bytes +2.10% none-before: 6 535 929 910 bytes none-after: 7 010 191 342 bytes +7.26% ### mozilla-try bzip-before: 6 583 425 999 bytes bzip-after: 7 423 536 928 bytes +12.76% zstd-before: 6 021 009 212 bytes zstd-after: 6 674 922 420 bytes +10.86% none-before: 22 954 739 558 bytes none-after: 26 013 854 771 bytes +13.32%

bundle: when forcing acceptance of incoming delta also accept snapshot Snapshot where never considered reusable and the unbundling side always tried to find a delta from them. In the `forced` mode this is counter-productive because it will either connect two delta-tree that should not be connected or it will spend potentially a lot of time because creating a full snapshot anyway. So in this mode, we accept the full snapshot as is. This changeset is benchmarked with its children so please do not split them apart when landing.

delta-find: properly report full snapshot used from cache as such The number of tries and the delta base is reported differently so we missed there detection initially.