revset: optimize missing ancestor expressions
A missing ancestor expression is any expression of the form (::x - ::y) or
equivalent. Such expressions are remarkably common, and so far have involved
multiple walks down the DAG, followed by a set difference operation.
With this patch, such expressions will be transformed into uses of the fast
algorithm at ancestor.missingancestor.
For a repository with over 600,000 revisions, perfrevset for '::tip - ::-10000'
returns:
Before: ! wall 3.999575 comb 4.000000 user 3.910000 sys 0.090000 (best of 3)
After: ! wall 0.132423 comb 0.130000 user 0.130000 sys 0.000000 (best of 75)
$ cat >> $HGRCPATH <<EOF
> [alias]
> tlog = log --template "{rev}:{node|short}: '{desc}' {branches}\n"
> tglog = tlog -G
> tout = out --template "{rev}:{node|short}: '{desc}' {branches}\n"
> EOF
$ hg init a
$ cd a
$ echo a > a
$ hg ci -Aqm0
$ echo foo >> a
$ hg ci -Aqm1
$ hg up -q 0
$ hg branch stable
marked working directory as branch stable
(branches are permanent and global, did you want a bookmark?)
$ echo bar >> a
$ hg ci -qm2
$ hg tglog
@ 2:7bee6c3bea3a: '2' stable
|
| o 1:3560197d8331: '1'
|/
o 0:f7b1eb17ad24: '0'
$ cd ..
$ hg clone -q a#stable b
$ cd b
$ cat .hg/hgrc
[paths]
default = $TESTTMP/a#stable (glob)
$ echo red >> a
$ hg ci -qm3
$ hg up -q default
$ echo blue >> a
$ hg ci -qm4
$ hg tglog
@ 3:f0461977a3db: '4'
|
| o 2:1d4099801a4e: '3' stable
| |
| o 1:7bee6c3bea3a: '2' stable
|/
o 0:f7b1eb17ad24: '0'
$ hg tout
comparing with $TESTTMP/a (glob)
searching for changes
2:1d4099801a4e: '3' stable
$ hg tlog -r 'outgoing()'
2:1d4099801a4e: '3' stable
$ hg tout ../a#default
comparing with ../a
searching for changes
3:f0461977a3db: '4'
$ hg tlog -r 'outgoing("../a#default")'
3:f0461977a3db: '4'
$ echo "green = ../a#default" >> .hg/hgrc
$ cat .hg/hgrc
[paths]
default = $TESTTMP/a#stable (glob)
green = ../a#default
$ hg tout green
comparing with $TESTTMP/a (glob)
searching for changes
3:f0461977a3db: '4'
$ hg tlog -r 'outgoing("green")'
3:f0461977a3db: '4'
$ cd ..