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.
Testing interaction of sparse and narrow when both are enabled on the client
side and we do a non-ellipsis clone
#testcases tree flat
$ . "$TESTDIR/narrow-library.sh"
$ cat << EOF >> $HGRCPATH
> [extensions]
> sparse =
> EOF
#if tree
$ cat << EOF >> $HGRCPATH
> [experimental]
> treemanifest = 1
> EOF
#endif
$ hg init master
$ cd master
$ mkdir inside
$ echo 'inside' > inside/f
$ hg add inside/f
$ hg commit -m 'add inside'
$ mkdir widest
$ echo 'widest' > widest/f
$ hg add widest/f
$ hg commit -m 'add widest'
$ mkdir outside
$ echo 'outside' > outside/f
$ hg add outside/f
$ hg commit -m 'add outside'
$ cd ..
narrow clone the inside file
$ hg clone --narrow ssh://user@dummy/master narrow --include inside/f
requesting all changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 1 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
$ hg tracked
I path:inside/f
$ hg files
inside/f
XXX: we should have a flag in `hg debugsparse` to list the sparse profile
$ test -f .hg/sparse
[1]
$ hg debugrequires
dotencode
dirstate-v2 (dirstate-v2 !)
fncache
generaldelta
narrowhg-experimental
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest (tree !)
$ hg debugrebuilddirstate
We only make the following assertions for the flat test case since in the
treemanifest test case debugsparse fails with "path ends in directory
separator: outside/" which seems like a bug unrelated to the regression this is
testing for.
#if flat
widening with both sparse and narrow is possible
$ cat >> .hg/hgrc <<EOF
> [extensions]
> sparse =
> narrow =
> EOF
$ hg debugsparse -X outside/f -X widest/f
$ hg tracked -q --addinclude outside/f
$ find . -name .hg -prune -o -type f -print | sort
./inside/f
$ hg debugsparse -d outside/f
$ find . -name .hg -prune -o -type f -print | sort
./inside/f
./outside/f
#endif