branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
#require serve
$ hg init server
$ hg serve -R server -p $HGPORT -d --pid-file=hg1.pid -E ../error.log
$ cat hg1.pid >> $DAEMON_PIDS
Check basic fetching
$ hg debugdownload "http://localhost:$HGPORT/?cmd=lookup&key=tip"
1 0000000000000000000000000000000000000000
$ hg debugdownload -o null.txt "http://localhost:$HGPORT/?cmd=lookup&key=null"
$ cat null.txt
1 0000000000000000000000000000000000000000
Check the request is made from the usual Mercurial logic
(rev details, give different content if the request has a Mercurial user agent)
$ get-with-headers.py --headeronly "localhost:$HGPORT" "rev/tip" content-type
200 Script output follows
content-type: text/html; charset=ascii
$ hg debugdownload "http://localhost:$HGPORT/rev/tip"
# HG changeset patch
# User
# Date 0 0
# Node ID 0000000000000000000000000000000000000000
Check other kind of compatible url
$ hg debugdownload ./null.txt
1 0000000000000000000000000000000000000000
$ cat ../error.log
Test largefile URL
------------------
$ cat << EOF >> $HGRCPATH
> [extensions]
> largefiles=
> EOF
$ killdaemons.py
$ rm -f error.log hg1.pid
$ hg serve -R server -p $HGPORT -d --pid-file=hg1.pid -E error.log
$ cat hg1.pid >> $DAEMON_PIDS
$ hg -R server debuglfput null.txt
a57b57b39ee4dc3da1e03526596007f480ecdbe8
$ hg debugdownload "largefile://a57b57b39ee4dc3da1e03526596007f480ecdbe8" --config paths.default=http://localhost:$HGPORT/
1 0000000000000000000000000000000000000000
from within a repository
$ hg clone http://localhost:$HGPORT/ client
no changes found
updating to branch default
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd client
$ hg path
default = http://localhost:$HGPORT/
$ hg debugdownload "largefile://a57b57b39ee4dc3da1e03526596007f480ecdbe8"
1 0000000000000000000000000000000000000000
$ cd ..
$ cat error.log