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.