status: prefer relative paths in Rust code
… when the repository root is under the current directory,
so the kernel needs to traverse fewer directory in every call
to `read_dir` or `symlink_metadata`.
Better yet would be to use libc functions like `openat` and `fstatat`
to remove such repeated traversals entirely, but the standard library
does not provide APIs based on those.
Maybe with a crate like https://crates.io/crates/openat instead?
Benchmarks of `rhg status` show that this patch is neutral in some configurations,
and makes the command up to ~20% faster in others.
Below is semi-arbitrary subset of results. The four numeric columns are:
time (in seconds) with this changeset’s parent, time with this changeset,
time difference (negative is better), time ratio (less than 1 is better).
```
mercurial-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.0061 -> 0.0059: -0.0002 (0.97)
mercurial-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0029 -> 0.0028: -0.0001 (0.97)
mozilla-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.2110 -> 0.2102: -0.0007 (1.00)
mozilla-dirstate-v2 | default-copies-clean.ignored.pbr | 0.0489 -> 0.0401: -0.0088 (0.82)
mozilla-dirstate-v2 | default-copies-clean.no-iu.pbr | 0.0479 -> 0.0393: -0.0085 (0.82)
mozilla-dirstate-v2 | default-copies-large.all.pbr | 0.1262 -> 0.1210: -0.0051 (0.96)
mozilla-dirstate-v2 | default-copies-small.ignored-unknown.pbr | 0.1262 -> 0.1200: -0.0062 (0.95)
mozilla-dirstate-v2 | default-copies-small.ignored.pbr | 0.0536 -> 0.0417: -0.0119 (0.78)
mozilla-dirstate-v2 | default-copies-small.no-iu.pbr | 0.0482 -> 0.0393: -0.0089 (0.81)
mozilla-dirstate-v2 | default-plain-clean.ignored.pbr | 0.0518 -> 0.0402: -0.0116 (0.78)
mozilla-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0481 -> 0.0392: -0.0088 (0.82)
mozilla-dirstate-v2 | default-plain-large.all.pbr | 0.1271 -> 0.1218: -0.0052 (0.96)
mozilla-dirstate-v2 | default-plain-small.ignored-unknown.pbr | 0.1225 -> 0.1202: -0.0022 (0.98)
mozilla-dirstate-v2 | default-plain-small.ignored.pbr | 0.0510 -> 0.0418: -0.0092 (0.82)
mozilla-dirstate-v2 | default-plain-small.no-iu.pbr | 0.0480 -> 0.0394: -0.0086 (0.82)
netbeans-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.1442 -> 0.1422: -0.0020 (0.99)
netbeans-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0325 -> 0.0282: -0.0043 (0.87)
```
Differential Revision: https://phab.mercurial-scm.org/D12175
#require unix-permissions no-root no-windows
Prepare
$ hg init a
$ echo a > a/a
$ hg -R a ci -A -m a
adding a
$ hg clone a b
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test that raising an exception in the release function doesn't cause the lock to choke
$ cat > testlock.py << EOF
> from mercurial import error, registrar
>
> cmdtable = {}
> command = registrar.command(cmdtable)
>
> def acquiretestlock(repo, releaseexc):
> def unlock():
> if releaseexc:
> raise error.Abort(b'expected release exception')
> l = repo._lock(repo.vfs, b'testlock', False, unlock, None, b'test lock')
> return l
>
> @command(b'testlockexc')
> def testlockexc(ui, repo):
> testlock = acquiretestlock(repo, True)
> try:
> testlock.release()
> finally:
> try:
> testlock = acquiretestlock(repo, False)
> except error.LockHeld:
> raise error.Abort(b'lockfile on disk even after releasing!')
> testlock.release()
> EOF
$ cat >> $HGRCPATH << EOF
> [extensions]
> testlock=$TESTTMP/testlock.py
> EOF
$ hg -R b testlockexc
abort: expected release exception
[255]
One process waiting for another
$ cat > hooks.py << EOF
> import time
> def sleepone(**x): time.sleep(1)
> def sleephalf(**x): time.sleep(0.5)
> EOF
$ echo b > b/b
$ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
$ hg -R b up -q --config ui.timeout.warn=0 --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
> > preup-stdout 2>preup-stderr
$ wait
$ cat preup-stdout
$ cat preup-stderr
waiting for lock on working directory of b held by process '*' on host '*' (glob)
got lock after * seconds (glob)
$ cat stdout
adding b
On processs waiting on another, warning after a long time.
$ echo b > b/c
$ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
$ hg -R b up -q --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
> --config ui.timeout.warn=250 \
> > preup-stdout 2>preup-stderr
$ wait
$ cat preup-stdout
$ cat preup-stderr
$ cat stdout
adding c
On processs waiting on another, warning disabled.
$ echo b > b/d
$ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
$ hg -R b up -q --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
> --config ui.timeout.warn=-1 \
> > preup-stdout 2>preup-stderr
$ wait
$ cat preup-stdout
$ cat preup-stderr
$ cat stdout
adding d
check we still print debug output
On processs waiting on another, warning after a long time (debug output on)
$ echo b > b/e
$ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
$ hg -R b up --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
> --config ui.timeout.warn=250 --debug\
> > preup-stdout 2>preup-stderr
$ wait
$ cat preup-stdout
calling hook pre-update: hghook_pre-update.sleephalf
waiting for lock on working directory of b held by process '*' on host '*' (glob)
got lock after * seconds (glob)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat preup-stderr
$ cat stdout
adding e
On processs waiting on another, warning disabled, (debug output on)
$ echo b > b/f
$ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
$ hg -R b up --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
> --config ui.timeout.warn=-1 --debug\
> > preup-stdout 2>preup-stderr
$ wait
$ cat preup-stdout
calling hook pre-update: hghook_pre-update.sleephalf
waiting for lock on working directory of b held by process '*' on host '*' (glob)
got lock after * seconds (glob)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat preup-stderr
$ cat stdout
adding f
Pushing to a local read-only repo that can't be locked
$ chmod 100 a/.hg/store
$ hg -R b push a
pushing to a
searching for changes
abort: could not lock repository a: Permission denied
[20]
$ chmod 700 a/.hg/store