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 execbit
$ umask 027
$ hg init test1
$ cd test1
$ touch a b
$ hg add a b
$ hg ci -m "added a b"
$ cd ..
$ hg clone test1 test3
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg init test2
$ cd test2
$ hg pull ../test1
pulling from ../test1
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
new changesets 22a449e20da5
(run 'hg update' to get a working copy)
$ hg co
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ chmod +x a
$ hg ci -m "chmod +x a"
the changelog should mention file a:
$ hg tip --template '{files}\n'
a
$ cd ../test1
$ echo 123 >>a
$ hg ci -m "a updated"
$ hg pull ../test2
pulling from ../test2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
new changesets 7f4313b42a34
1 local changesets published
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg heads
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:c6ecefc45368
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a updated
$ hg history
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:c6ecefc45368
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a updated
changeset: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: added a b
$ hg -v merge
resolving manifests
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat a
123
$ [ -x a ]
$ cd ../test3
$ echo 123 >>b
$ hg ci -m "b updated"
$ hg pull ../test2
pulling from ../test2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
new changesets 7f4313b42a34
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg heads
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:dc57ead75f79
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: b updated
$ hg history
changeset: 2:7f4313b42a34
tag: tip
parent: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: chmod +x a
changeset: 1:dc57ead75f79
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: b updated
changeset: 0:22a449e20da5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: added a b
$ hg -v merge
resolving manifests
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ ls -l ../test[123]/a > foo
$ cut -b 1-10 < foo
-rwxr-x---
-rwxr-x---
-rwxr-x---
$ hg debugindex a
rev linkrev nodeid p1 p2
0 0 b80de5d13875 000000000000 000000000000
$ hg debugindex -R ../test2 a
rev linkrev nodeid p1 p2
0 0 b80de5d13875 000000000000 000000000000
$ hg debugindex -R ../test1 a
rev linkrev nodeid p1 p2
0 0 b80de5d13875 000000000000 000000000000
1 1 7fe919cc0336 b80de5d13875 000000000000
$ cd ..