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)
Initial setup.
$ hg init repo
$ cd repo
$ touch thefile
$ hg ci -A -m 'Initial commit.'
adding thefile
Create a tag.
$ hg tag branchortag
Create a branch with the same name as the tag.
$ hg branch branchortag
marked working directory as branch branchortag
(branches are permanent and global, did you want a bookmark?)
$ hg ci -m 'Create a branch with the same name as a tag.'
This is what we have:
$ hg log
changeset: 2:10519b3f489a
branch: branchortag
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Create a branch with the same name as a tag.
changeset: 1:2635c45ca99b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag branchortag for changeset f57387372b5d
changeset: 0:f57387372b5d
tag: branchortag
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Initial commit.
Update to the tag:
$ hg up 'tag(branchortag)'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg parents
changeset: 0:f57387372b5d
tag: branchortag
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Initial commit.
Updating to the branch:
$ hg up 'branch(branchortag)'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg parents
changeset: 2:10519b3f489a
branch: branchortag
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Create a branch with the same name as a tag.
$ cd ..