revisionbranchcache: fall back to slow path if starting readonly (issue4531)
Transitioning to Mercurial versions with revision branch cache could be slow as
long as all operations were readonly (revset queries) and the cache would be
populated but not written back.
Instead, fall back to using the consistently slow path when readonly and the
cache doesn't exist yet. That avoids the overhead of populating the cache
without writing it back.
If not readonly, it will still populate all missing entries initially. That
avoids repeated writing of the cache file with small updates, and it also makes
sure a fully populated cache available for the readonly operations.
$ 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
# example repository config (see "hg help config" for more info)
[paths]
default = $TESTTMP/a#stable (glob)
# path aliases to other clones of this repo in URLs or filesystem paths
# (see "hg help config.paths" for more info)
#
# default-push = ssh://jdoe@example.net/hg/jdoes-fork
# my-fork = ssh://jdoe@example.net/hg/jdoes-fork
# my-clone = /home/jdoe/jdoes-clone
[ui]
# name and email (local to this repository, optional), e.g.
# username = Jane Doe <jdoe@example.com>
$ 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
# example repository config (see "hg help config" for more info)
[paths]
default = $TESTTMP/a#stable (glob)
# path aliases to other clones of this repo in URLs or filesystem paths
# (see "hg help config.paths" for more info)
#
# default-push = ssh://jdoe@example.net/hg/jdoes-fork
# my-fork = ssh://jdoe@example.net/hg/jdoes-fork
# my-clone = /home/jdoe/jdoes-clone
[ui]
# name and email (local to this repository, optional), e.g.
# username = Jane Doe <jdoe@example.com>
green = ../a#default
$ hg tout green
comparing with green
abort: repository green not found!
[255]
$ hg tlog -r 'outgoing("green")'
abort: repository green not found!
[255]
$ cd ..