update: add a Rust fast-path when updating from null (and clean)
This case is easy to detect and we have all we need to generate a valid
working copy and dirstate entirely in Rust, which speeds things up
considerably:
On my machine updating a repo of ~300k files goes from 10.00s down to 4.2s,
all while consuming 50% less system time, with all caches hot.
Something to note is that further improvements will probably happen
with the upcoming `InnerRevlog` series that does smarter
mmap hanlding, especially for filelogs.
Here are benchmark numbers on a machine with only 4 cores (and no SMT enabled)
```
### data-env-vars.name = heptapod-public-2024-03-25-ds2-pnm
# benchmark.name = hg.command.update
# bin-env-vars.hg.py-re2-module = default
# bin-env-vars.hg.changeset.node = <this change>
# benchmark.variants.atomic-update = no
# benchmark.variants.scenario = null-to-tip
# benchmark.variants.worker = default
default: 5.328762 ~~~~~
rust: 1.308654 (-75.44%, -4.02)
### data-env-vars.name = mercurial-devel-2024-03-22-ds2-pnm
# benchmark.name = hg.command.update
# bin-env-vars.hg.py-re2-module = default
# bin-env-vars.hg.changeset.node = <this change>
# benchmark.variants.atomic-update = no
# benchmark.variants.scenario = null-to-tip
# benchmark.variants.worker = default
default: 1.693271 ~~~~~
rust: 1.151053 (-32.02%, -0.54)
### data-env-vars.name = mozilla-unified-2024-03-22-ds2-pnm
# benchmark.name = hg.command.update
# bin-env-vars.hg.py-re2-module = default
# bin-env-vars.hg.changeset.node = <this change>
# benchmark.variants.atomic-update = no
# benchmark.variants.scenario = null-to-tip
# benchmark.variants.worker = default
default: 38.901613 ~~~~~
rust: 11.637880 (-70.08%, -27.26)
### data-env-vars.name = netbsd-xsrc-public-2024-09-19-ds2-pnm
# benchmark.name = hg.command.update
# bin-env-vars.hg.py-re2-module = default
# bin-env-vars.hg.changeset.node = <this change>
# benchmark.variants.atomic-update = no
# benchmark.variants.scenario = null-to-tip
# benchmark.variants.worker = default
default: 4.793727 ~~~~~
rust: 1.505905 (-68.59%, -3.29)
```
#require unix-permissions
test that new files created in .hg inherit the permissions from .hg/store
$ mkdir dir
just in case somebody has a strange $TMPDIR
$ chmod g-s dir
$ cd dir
$ cat >printmodes.py <<EOF
> import os
> import sys
>
> allnames = []
> isdir = {}
> for root, dirs, files in os.walk(sys.argv[1]):
> for d in dirs:
> name = os.path.join(root, d)
> isdir[name] = 1
> allnames.append(name)
> for f in files:
> name = os.path.join(root, f)
> allnames.append(name)
> allnames.sort()
> for name in allnames:
> suffix = name in isdir and '/' or ''
> print('%05o %s%s' % (os.lstat(name).st_mode & 0o7777, name, suffix))
> EOF
$ cat >mode.py <<EOF
> import os
> import sys
> print('%05o' % os.lstat(sys.argv[1]).st_mode)
> EOF
$ umask 077
$ hg init repo
$ cd repo
$ chmod 0770 .hg/store .hg/cache .hg/wcache
before commit
store can be written by the group, other files cannot
store is setgid
$ "$PYTHON" ../printmodes.py .
00700 ./.hg/
00600 ./.hg/00changelog.i
00770 ./.hg/cache/
00600 ./.hg/requires
00770 ./.hg/store/
00600 ./.hg/store/requires
00770 ./.hg/wcache/
$ mkdir dir
$ touch foo dir/bar
$ hg ci -qAm 'add files'
after commit
working dir files can only be written by the owner
files created in .hg can be written by the group
(in particular, store/**, dirstate, branch cache file, undo files)
new directories are setgid
$ "$PYTHON" ../printmodes.py .
00700 ./.hg/
00600 ./.hg/00changelog.i
00660 ./.hg/branch
00770 ./.hg/cache/
00660 ./.hg/cache/branch2-served
00660 ./.hg/cache/rbc-names-v2
00660 ./.hg/cache/rbc-revs-v2
00660 ./.hg/dirstate
00660 ./.hg/fsmonitor.state (fsmonitor !)
00660 ./.hg/last-message.txt
00600 ./.hg/requires
00770 ./.hg/store/
00660 ./.hg/store/00changelog-150e1cfc.nd (rust !)
00660 ./.hg/store/00changelog.d
00660 ./.hg/store/00changelog.i
00660 ./.hg/store/00changelog.n (rust !)
00660 ./.hg/store/00manifest.i
00770 ./.hg/store/data/
00770 ./.hg/store/data/dir/
00660 ./.hg/store/data/dir/bar.i (reporevlogstore !)
00660 ./.hg/store/data/foo.i (reporevlogstore !)
00770 ./.hg/store/data/dir/bar/ (reposimplestore !)
00660 ./.hg/store/data/dir/bar/b80de5d138758541c5f05265ad144ab9fa86d1db (reposimplestore !)
00660 ./.hg/store/data/dir/bar/index (reposimplestore !)
00770 ./.hg/store/data/foo/ (reposimplestore !)
00660 ./.hg/store/data/foo/b80de5d138758541c5f05265ad144ab9fa86d1db (reposimplestore !)
00660 ./.hg/store/data/foo/index (reposimplestore !)
00660 ./.hg/store/fncache (repofncache !)
00660 ./.hg/store/phaseroots
00600 ./.hg/store/requires
00660 ./.hg/store/undo
00660 ./.hg/store/undo.backupfiles
00660 ./.hg/undo.backup.branch.bck
00660 ./.hg/undo.desc
00770 ./.hg/wcache/
00711 ./.hg/wcache/checkisexec
007.. ./.hg/wcache/checklink (re)
00600 ./.hg/wcache/checklink-target
00660 ./.hg/wcache/manifestfulltextcache (reporevlogstore !)
00700 ./dir/
00600 ./dir/bar
00600 ./foo
$ umask 007
$ hg init ../push
before push
group can write everything
$ "$PYTHON" ../printmodes.py ../push
00770 ../push/.hg/
00660 ../push/.hg/00changelog.i
00770 ../push/.hg/cache/
00660 ../push/.hg/requires
00770 ../push/.hg/store/
00660 ../push/.hg/store/requires
00770 ../push/.hg/wcache/
$ umask 077
$ hg -q push ../push
after push
group can still write everything
$ "$PYTHON" ../printmodes.py ../push
00770 ../push/.hg/
00660 ../push/.hg/00changelog.i
00660 ../push/.hg/branch
00770 ../push/.hg/cache/
00660 ../push/.hg/cache/branch2-base
00660 ../push/.hg/cache/rbc-names-v2
00660 ../push/.hg/cache/rbc-revs-v2
00660 ../push/.hg/requires
00770 ../push/.hg/store/
00660 ../push/.hg/store/00changelog-b870a51b.nd (rust !)
00660 ../push/.hg/store/00changelog.d
00660 ../push/.hg/store/00changelog.i
00660 ../push/.hg/store/00changelog.n (rust !)
00660 ../push/.hg/store/00manifest.i
00770 ../push/.hg/store/data/
00770 ../push/.hg/store/data/dir/
00660 ../push/.hg/store/data/dir/bar.i (reporevlogstore !)
00660 ../push/.hg/store/data/foo.i (reporevlogstore !)
00770 ../push/.hg/store/data/dir/bar/ (reposimplestore !)
00660 ../push/.hg/store/data/dir/bar/b80de5d138758541c5f05265ad144ab9fa86d1db (reposimplestore !)
00660 ../push/.hg/store/data/dir/bar/index (reposimplestore !)
00770 ../push/.hg/store/data/foo/ (reposimplestore !)
00660 ../push/.hg/store/data/foo/b80de5d138758541c5f05265ad144ab9fa86d1db (reposimplestore !)
00660 ../push/.hg/store/data/foo/index (reposimplestore !)
00660 ../push/.hg/store/fncache (repofncache !)
00660 ../push/.hg/store/requires
00660 ../push/.hg/store/undo
00660 ../push/.hg/store/undo.backupfiles
00660 ../push/.hg/undo.backup.branch.bck
00660 ../push/.hg/undo.desc
00770 ../push/.hg/wcache/
Test that we don't lose the setgid bit when we call chmod.
Not all systems support setgid directories (e.g. HFS+), so
just check that directories have the same mode.
$ cd ..
$ hg init setgid
$ cd setgid
$ chmod g+rwx .hg/store
$ chmod g+s .hg/store 2> /dev/null || true
$ mkdir dir
$ touch dir/file
$ hg ci -qAm 'add dir/file'
$ storemode=`"$PYTHON" ../mode.py .hg/store`
$ dirmode=`"$PYTHON" ../mode.py .hg/store/data/dir`
$ if [ "$storemode" != "$dirmode" ]; then
> echo "$storemode != $dirmode"
> fi
$ cd ..
$ cd .. # g-s dir