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.
$ . "$TESTDIR/narrow-library.sh"
create full repo
$ hg init master
$ cd master
$ mkdir inside
$ echo inside > inside/f1
$ mkdir outside
$ echo outside > outside/f2
$ hg ci -Aqm 'initial'
$ hg mv outside/f2 inside/f2
$ hg ci -qm 'move f2 from outside'
$ echo modified > inside/f2
$ hg ci -qm 'modify inside/f2'
$ mkdir outside
$ echo new > outside/f3
$ hg ci -Aqm 'add outside/f3'
$ cd ..
$ hg clone --narrow ssh://user@dummy/master narrow --include inside -r 2
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 2 files
new changesets *:* (glob)
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd narrow
$ hg co 'desc("move f2")'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg status
$ hg diff
$ hg diff --change . --git
diff --git a/inside/f2 b/inside/f2
new file mode 100644
--- /dev/null
+++ b/inside/f2
@@ -0,0 +1,1 @@
+outside
$ hg log --follow inside/f2 -r tip
changeset: 2:bcfb756e0ca9
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify inside/f2
changeset: 1:5a016133b2bb
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: move f2 from outside
$ echo new > inside/f4
$ hg ci -Aqm 'add inside/f4'
$ hg pull -q
$ hg --config extensions.rebase= rebase -d tip
rebasing 3:4f84b666728c "add inside/f4"
saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/4f84b666728c-4269b76e-rebase.hg
$ hg co -q 0
$ echo modified > inside/f1
$ hg ci -qm 'modify inside/f1'
$ echo new > inside/f5
$ hg ci -Aqm 'add inside/f5'
$ hg --config extensions.rebase= rebase -d 'public()' -r .
rebasing 6:610b60178c28 tip "add inside/f5"
saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/610b60178c28-65716a78-rebase.hg