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
$ cat >> $HGRCPATH << EOF
> [extensions]
> show =
> EOF
$ hg init repo0
$ cd repo0
Command works on an empty repo
$ hg show work
Single draft changeset shown
$ echo 0 > foo
$ hg -q commit -A -m 'commit 0'
$ hg show work
@ 9f17 commit 0
Even when it isn't the wdir
$ hg -q up null
$ hg show work
o 9f17 commit 0
Single changeset is still there when public because it is a head
$ hg phase --public -r 0
$ hg show work
o 9f17 commit 0
A draft child will show both it and public parent
$ hg -q up 0
$ echo 1 > foo
$ hg commit -m 'commit 1'
$ hg show work
@ 181c commit 1
o 9f17 commit 0
Multiple draft children will be shown
$ echo 2 > foo
$ hg commit -m 'commit 2'
$ hg show work
@ 128c commit 2
o 181c commit 1
o 9f17 commit 0
Bumping first draft changeset to public will hide its parent
$ hg phase --public -r 1
$ hg show work
@ 128c commit 2
o 181c commit 1
~
Multiple DAG heads will be shown
$ hg -q up -r 1
$ echo 3 > foo
$ hg commit -m 'commit 3'
created new head
$ hg show work
@ f0ab commit 3
| o 128c commit 2
|/
o 181c commit 1
~
Even when wdir is something else
$ hg -q up null
$ hg show work
o f0ab commit 3
| o 128c commit 2
|/
o 181c commit 1
~
Draft child shows public head (multiple heads)
$ hg -q up 0
$ echo 4 > foo
$ hg commit -m 'commit 4'
created new head
$ hg show work
@ 668c commit 4
| o f0ab commit 3
| | o 128c commit 2
| |/
| o 181c commit 1
|/
o 9f17 commit 0
$ cd ..
Branch name appears in output
$ hg init branches
$ cd branches
$ echo 0 > foo
$ hg -q commit -A -m 'commit 0'
$ echo 1 > foo
$ hg commit -m 'commit 1'
$ echo 2 > foo
$ hg commit -m 'commit 2'
$ hg phase --public -r .
$ hg -q up -r 1
$ hg branch mybranch
marked working directory as branch mybranch
(branches are permanent and global, did you want a bookmark?)
$ echo 3 > foo
$ hg commit -m 'commit 3'
$ echo 4 > foo
$ hg commit -m 'commit 4'
$ hg show work
@ f8dd (mybranch) commit 4
o 90cf (mybranch) commit 3
| o 128c commit 2
|/
o 181c commit 1
~
$ cd ..
Bookmark name appears in output
$ hg init bookmarks
$ cd bookmarks
$ echo 0 > foo
$ hg -q commit -A -m 'commit 0'
$ echo 1 > foo
$ hg commit -m 'commit 1'
$ echo 2 > foo
$ hg commit -m 'commit 2'
$ hg phase --public -r .
$ hg bookmark @
$ hg -q up -r 1
$ echo 3 > foo
$ hg commit -m 'commit 3'
created new head
$ echo 4 > foo
$ hg commit -m 'commit 4'
$ hg bookmark mybook
$ hg show work
@ cac8 (mybook) commit 4
o f0ab commit 3
| o 128c (@) commit 2
|/
o 181c commit 1
~
$ cd ..
Tags are rendered
$ hg init tags
$ cd tags
$ echo 0 > foo
$ hg -q commit -A -m 'commit 1'
$ echo 1 > foo
$ hg commit -m 'commit 2'
$ hg tag 0.1
$ hg phase --public -r .
$ echo 2 > foo
$ hg commit -m 'commit 3'
$ hg tag 0.2
$ hg show work
@ 3758 Added tag 0.2 for changeset 6379c25b76f1
o 6379 (0.2) commit 3
o a2ad Added tag 0.1 for changeset 6a75536ea0b1
~
$ cd ..
Multiple names on same changeset render properly
$ hg init multiplenames
$ cd multiplenames
$ echo 0 > foo
$ hg -q commit -A -m 'commit 1'
$ hg phase --public -r .
$ hg branch mybranch
marked working directory as branch mybranch
(branches are permanent and global, did you want a bookmark?)
$ hg bookmark mybook
$ echo 1 > foo
$ hg commit -m 'commit 2'
$ hg show work
@ 3483 (mybook) (mybranch) commit 2
o 97fc commit 1
Multiple bookmarks on same changeset render properly
$ hg book mybook2
$ hg show work
@ 3483 (mybook mybook2) (mybranch) commit 2
o 97fc commit 1
$ cd ..
Extra namespaces are rendered
$ hg init extranamespaces
$ cd extranamespaces
$ echo 0 > foo
$ hg -q commit -A -m 'commit 1'
$ hg phase --public -r .
$ echo 1 > foo
$ hg commit -m 'commit 2'
$ echo 2 > foo
$ hg commit -m 'commit 3'
$ hg --config extensions.revnames=$TESTDIR/revnamesext.py show work
@ 32f3 (r2) commit 3
o 6a75 (r1) commit 2
o 97fc (r0) commit 1
Obsolescence information appears in labels.
$ cat >> .hg/hgrc << EOF
> [experimental]
> evolution=createmarkers
> EOF
$ hg debugobsolete `hg log -r 'desc("commit 2")' -T "{node}"`
1 new obsolescence markers
obsoleted 1 changesets
1 new orphan changesets
$ hg show work --color=debug
@ [log.changeset changeset.draft changeset.unstable instability.orphan|32f3] [log.description|commit 3]
x [log.changeset changeset.draft changeset.obsolete|6a75] [log.description|commit 2]
~
$ cd ..
Prefix collision on hashes increases shortest node length
$ hg init hashcollision
$ cd hashcollision
$ echo 0 > a
$ hg -q commit -Am 0
$ for i in 17 1057 2857 4025; do
> hg -q up 0
> echo $i > a
> hg -q commit -m $i
> echo 0 > a
> hg commit -m "$i commit 2"
> done
$ hg show work
@ cfd04 4025 commit 2
o c562d 4025
| o 08048 2857 commit 2
| o c5623 2857
|/
| o 6a6b6 1057 commit 2
| o c5625 1057
|/
| o 96b4e 17 commit 2
| o 11424 17
|/
o b4e73 0
$ cd ..