tags-cache: directly perform a monimal walk for hgtagsfnodescache warming We do something narrower than the path retrieving data. So lets use dedicated code instead. This provides further useful speedup: ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.debug.debug-update-cache # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.pre-state = warm before-this-series: 19.947581 skip-fnode-filter: 18.916804 (-5.17%, -1.03) use-rev-num: 17.493725 (-12.30%, -2.45) this-changesets: 15.919466 (-20.19%, -4.03)

  $ hg init repo
  $ cd repo

  $ touch foo
  $ hg ci -Am 'add foo'
  adding foo

  $ hg up -C null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

this should be stored as a delta against rev 0

  $ echo foo bar baz > foo
  $ hg ci -Am 'add foo again'
  adding foo
  created new head

  $ hg debugindex foo
     rev linkrev       nodeid    p1-nodeid    p2-nodeid
       0       0 b80de5d13875 000000000000 000000000000
       1       1 0376abec49b8 000000000000 000000000000

  $ cd ..