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.
Test hg log changeset printer external hook
-------------------------------------------
$ cat > $TESTTMP/logexthook.py <<EOF
> import codecs
> from mercurial import (
> commands,
> logcmdutil,
> repair,
> )
> def brot13(b):
> return codecs.encode(b.decode('utf8'), 'rot-13').encode('utf8')
> def rot13description(self, ctx):
> description = ctx.description().strip().splitlines()[0]
> self.ui.write(b"%s: %s\n" % (brot13(b"summary"),
> brot13(description)))
> def reposetup(ui, repo):
> logcmdutil.changesetprinter._exthook = rot13description
> EOF
Prepare the repository
$ hg init empty
$ cd empty
$ touch ROOT
$ hg commit -A -m "Root" ROOT
$ touch a b c
$ hg commit -A -m "Add A, B, C" a b c
Check the log
$ hg log --config extensions.t=$TESTTMP/logexthook.py
changeset: 1:70fc82b23320
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
fhzznel: Nqq N, O, P
summary: Add A, B, C
changeset: 0:b00443a54871
user: test
date: Thu Jan 01 00:00:00 1970 +0000
fhzznel: Ebbg
summary: Root
Check that exthook is working with graph log too
$ hg log -G --config extensions.t=$TESTTMP/logexthook.py
@ changeset: 1:70fc82b23320
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| fhzznel: Nqq N, O, P
| summary: Add A, B, C
|
o changeset: 0:b00443a54871
user: test
date: Thu Jan 01 00:00:00 1970 +0000
fhzznel: Ebbg
summary: Root