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
=========================================================
Test features and behaviors related to the archived phase
=========================================================
$ cat << EOF >> $HGRCPATH
> [format]
> internal-phase=yes
> [extensions]
> strip=
> [experimental]
> EOF
$ hg init repo
$ cd repo
$ echo root > a
$ hg add a
$ hg ci -m 'root'
Test that bundle can unarchive a changeset
------------------------------------------
$ echo foo >> a
$ hg st
M a
$ hg ci -m 'unbundletesting'
$ hg log -G
@ changeset: 1:883aadbbf309
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
o changeset: 0:c1863a3840c6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root
$ hg strip --soft --rev '.'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/883aadbbf309-efc55adc-backup.hg
$ hg log -G
@ changeset: 0:c1863a3840c6
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root
$ hg log -G --hidden
o changeset: 1:883aadbbf309
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
@ changeset: 0:c1863a3840c6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root
$ hg unbundle .hg/strip-backup/883aadbbf309-efc55adc-backup.hg
adding changesets
adding manifests
adding file changes
added 0 changesets with 0 changes to 1 files
(run 'hg update' to get a working copy)
$ hg log -G
o changeset: 1:883aadbbf309
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
@ changeset: 0:c1863a3840c6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root
Test that history rewriting command can use the archived phase when allowed to
------------------------------------------------------------------------------
$ hg up 'desc(unbundletesting)'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo bar >> a
$ hg commit --amend --config experimental.cleanup-as-archived=yes
$ hg log -G
@ changeset: 2:d1e73e428f29
| tag: tip
| parent: 0:c1863a3840c6
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
o changeset: 0:c1863a3840c6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root
$ hg log -G --hidden
@ changeset: 2:d1e73e428f29
| tag: tip
| parent: 0:c1863a3840c6
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
| o changeset: 1:883aadbbf309
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
o changeset: 0:c1863a3840c6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root
$ ls -1 .hg/strip-backup/
883aadbbf309-efc55adc-amend.hg
883aadbbf309-efc55adc-backup.hg
$ hg unbundle .hg/strip-backup/883aadbbf309*amend.hg
adding changesets
adding manifests
adding file changes
added 0 changesets with 0 changes to 1 files
(run 'hg update' to get a working copy)
$ hg log -G
@ changeset: 2:d1e73e428f29
| tag: tip
| parent: 0:c1863a3840c6
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
| o changeset: 1:883aadbbf309
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: unbundletesting
|
o changeset: 0:c1863a3840c6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: root