diff mercurial/repoview.py @ 51406:f8bf1a8e9181

phases: keep internal state as rev-num instead of node-id

Node-id are expensive to work with, dealing with revision is much simple and
faster.

The fact we still used node-id here shows how few effort have been put into
making the phase logic fast. We tend to no longer use node-id internally for
about ten years.

This has a large impact of repository with many draft roots. For example this
Mozilla-try copy have ½ Million draft roots and `perf::unbundle` see a
significant improvement.

### 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-1
before:: 1.746791 seconds
after::  1.278379 seconds  (-26.82%)

  # benchmark.variants.revs = last-10
before:: 3.145774 seconds
after::  2.103735 seconds  (-33.13%)

  # benchmark.variants.revs = last-100
before:: 3.487635 seconds
after::  2.446749 seconds  (-29.85%)

  # benchmark.variants.revs = last-1000
before:: 5.007568 seconds
after::  3.989923 seconds  (-20.32%)

--- a/mercurial/repoview.py	Tue Feb 20 21:40:08 2024 +0100
+++ b/mercurial/repoview.py	Tue Feb 20 21:40:13 2024 +0100
@@ -160,7 +160,7 @@
     firstmutable = len(cl)
     roots = repo._phasecache.nonpublicphaseroots(repo)
     if roots:
-        firstmutable = min(firstmutable, min(cl.rev(r) for r in roots))
+        firstmutable = min(firstmutable, min(roots))
     # protect from nullrev root
     firstmutable = max(0, firstmutable)
     return frozenset(range(firstmutable, len(cl)))