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.
#testcases flat tree
$ . "$TESTDIR/narrow-library.sh"
#if tree
$ cat << EOF >> $HGRCPATH
> [experimental]
> treemanifest = 1
> EOF
#endif
create full repo
$ hg init master
$ cd master
$ mkdir inside
$ echo inside > inside/f1
$ mkdir outside
$ echo outside > outside/f1
$ hg ci -Aqm 'initial'
$ echo modified > inside/f1
$ hg ci -qm 'modify inside'
$ echo modified > outside/f1
$ hg ci -qm 'modify outside'
$ cd ..
$ hg clone --narrow ssh://user@dummy/master narrow --include inside
requesting all changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 2 changes to 1 files
new changesets *:* (glob)
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd narrow
Can show patch touching paths outside
$ hg log -p
changeset: 2:* (glob)
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify outside
changeset: 1:* (glob)
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify inside
diff -r * -r * inside/f1 (glob)
--- a/inside/f1 Thu Jan 01 00:00:00 1970 +0000
+++ b/inside/f1 Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-inside
+modified
changeset: 0:* (glob)
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: initial
diff -r 000000000000 -r * inside/f1 (glob)
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/inside/f1 Thu Jan 01 00:00:00 1970 +0000
@@ -0,0 +1,1 @@
+inside
$ hg status --rev 1 --rev 2
Can show copies inside the narrow clone
$ hg cp inside/f1 inside/f2
$ hg diff --git
diff --git a/inside/f1 b/inside/f2
copy from inside/f1
copy to inside/f2