perf: add a --as-push option to perf::unbundle This turned out to make a quite significant difference.

chainsaw-update: exit early if one of the intermediate command fails That will prevent the user to be presented with a start that pretend to be consistent with the request, but is not.

chainsaw-update: lock the repository for the duration of the operation This should prevent and catch some misusage where something else try to touch the repository.

chainsaw-update: taking care of initial cloning Perhaps we should go just a bit lower level than this `instance()`, since the main added value in our use-case is full path resolution, that we need to do anyway for the rmtree cleanup.

chainsaw-update: use a graph with branching in graph This will be relevant for the next improvement of `chainsaw-update`.

chainsaw-update: log actual locks breaking Previously, the command would simply state that it was about to break locks, not if there was actually some to break. This version is race-free. It would be also possible to display the content of the lock before hand (not race-free but informative in almost all cases).

vfs: have tryunlink tell what it did It is useful in certain circumstances to know whether vfs.tryunlink() actually removed something or not, be it for logging purposes.

chainsaw: new extension for dangerous operations The first provided command is `chainsaw-update`, whose one and single job is to make sure that it will pull, update and purge the target repository, no matter what may be in the way (locks, notably), see docstring for rationale.

rust: disable the RustIndex without persistent nodemap See rational inline.

rust: stop claiming the C index is compatible with the rust code This is no longer the case since the introduction of the pure Rust Index, and was probably not the case since the MixedIndex itself. So we fix the dedicated attribute value.

rust-index: remove one collect when converting back Turns out this is slightly faster. Sending the results back to Python is still the most costly (like 75% of the time) of the whole method, but it's about as fast as it can be now. hg perf::phases on mozilla-try-2023-03-22 before: 0.267114 after: 0.247101

rust-index: improve phase computation speed While less memory efficient, using an array is *much* faster than using a HashMap, especially with the default hasher. It even makes the code simpler, so I'm not really sure what I was thinking in the first place, maybe it's more obvious now. This fix a significant performance regression when using the rust version of the code. (however, the C code still outperform rust on this operation) hg perf::phases on mozilla-try-2023-03-22 - 6.6.3: 0.451239 seconds - before: 0.982495 seconds - after: 0.265347 seconds - C code: 0.183241 second

phases: directly update the phase sets in advanceboundary This is similar to what we do in retractboundary. There is no need to invalidate the cache if we have everything at hand to update it.

phases: large rework of advance boundary In a similar spirit as the rework of retractboundary, the new algorithm is doing an amount of work in the order of magnitude of the amount of changeset that changes phases. (except to find new roots in impacted higher phases if any may exists). This result in a very significant speedup for repository with many old draft like mozilla try. runtime of perf:unbundle for a bundle constaining a single changeset (C code): before 6.7 phase work: 14.497 seconds before this change: 6.311 seconds (-55%) with this change: 2.240 seconds (-85%) Combined with the other patches that fixes the phases computation in the Rust index, the rust code with a persistent nodemap get back to quite interresting performances with 2.026 seconds for the same operation, about 10% faster than the C code.

phases: apply similar early filtering to advanceboundary advanceboundary is called the push's unbundle (but not the other unbundle) so advanceboundary did not show up the profile I looked at so far. We start with simple pre-filtering to avoid doing any work if we don't needs too.

phases: filter revision that are already in the right phase No need to compute new roots if everything is already in order.

phases: invalidate the phases set less often on retract boundary We already have the information to update the phase set, so we do so directly instead of invalidating the cache. This show a sizeable speedup in our `perf::unbundle` benchmark on the many-draft mozilla-try repository. ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.perf.perf-unbundle # bin-env-vars.hg.flavor = no-rust # bin-env-vars.hg.py-re2-module = default # benchmark.variants.issue6528 = disabled # benchmark.variants.revs = last-10 before: 2.055259 seconds after: 1.887064 seconds (-8.18%) # benchmark.variants.revs = last-100 before: 2.409239 seconds after: 2.222429 seconds (-7.75%) # benchmark.variants.revs = last-1000 before: 3.945648 seconds after: 3.762480 seconds (-4.64%)

phases: incrementally update the phase sets when reasonable When the amount of manual walking is small, we update the phases set manually instead of computing them from scratch. This should help small update. The next changesets will make this used more often by reducing the amount of full invalidation we do on roots upgrade. The criteria for using an incremental upgrade are arbitrary, however, it "should never hurt".

phasees: properly shallow caopy the phase sets dictionary We are about to increments the set more incrementally in some case, so we need to make a proper shallow copy of it.

phases: pass an unfiltered repository to _ensure_phase_sets It seems better for such a low level function to be able to assume it operate on a real repository.

phases: drop set building in `hasnonpublicphases` We don't actually use the set, so why do we ensure they are built? (we should also clean up the use of repository argument but that's a quest for later).

phases: gather the logic for phasesets update in a single method This logic is duplicated around for no good reason, we gather it in a single place. The conditional is the new function are a bit weird as we about going to extend it soon.

phases: change the way we warm the phasecache in repocache Same logic as for the previous chngeset. We are about to rename and change the method used here.

phases: use a more generic way to trigger a phases computation for perf Querying the tip most revision will require the cache to warm the same as calling the dedicated method. This avoid using a method that is mostly meant for internal use and will be renamed in a coming changesets.

phases: fix an overzealous invalidation of the phase sets If `len(cl) == self._loadedrevslen` the cache is up to date.

phases: type annotation for `_phasesets` Does not hurt.

phases: leverage the collected information to record phase update Since the lower level function already gather this information, we can directly use it. This comes with a small change to the test that are actually fixing them. The previous version over-reported some phase change that did not exists. In both case, we are force revision `1` to be secret and `0` remains draft`, the previous code wrongly reported `0` as moving to secret while it properly remained draft in the repository.

phases: large rewrite on retract boundary The new code is still pure Python, so we still have room to going significantly faster. However its complexity of the complex part is `O(|[min_new_draft, tip]|)` instead of `O(|[min_draft, tip]|` which should help tremendously one repository with old draft (like mercurial-devel or mozilla-try). This is especially useful as the most common "retract boundary" operation happens when we commit/rewrite new drafts or when we push new draft to a non-publishing server. In this case, the smallest new_revs is very close to the tip and there is very few work to do. A few smaller optimisation could be done for these cases and will be introduced in later changesets. We still have iterate over large sets of roots, but this is already a great improvement for a very small amount of work. We gather information on the affected changeset as we go as we can put it to use in the next changesets. This extra data collection might slowdown the `register_new` case a bit, however for register_new, it should not really matters. The set of new nodes is either small, so the impact is negligible, or the set of new nodes is large, and the amount of work to do to had them will dominate the overhead the collecting information in `changed_revs`. As this new code compute the changes on the fly, it unlock other interesting improvement to be done in later changeset.

phases: fast path public phase advance when everything is public Everything is already public, so we have nothing to do here.

phases: fast path retract of public phase There are no boundary to retract, so lets do nothing.