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 no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ echo treemanifest >> .hg/requires
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
# uppercase directory name to test encoding
$ mkdir -p A/B
$ echo x > A/B/x
$ hg commit -qAm x
$ cd ..
# shallow clone from full
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
5 files to transfer, 449 bytes of data (no-rust !)
transferred 449 bytes in * seconds (*/sec) (glob) (no-rust !)
7 files to transfer, 575 bytes of data (rust !)
transferred 575 bytes in *.* seconds (*) (glob) (rust !)
searching for changes
no changes found
$ cd shallow
$ hg debugrequires
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest
$ find .hg/store/meta | sort
.hg/store/meta
.hg/store/meta/_a
.hg/store/meta/_a/00manifest.i
.hg/store/meta/_a/_b
.hg/store/meta/_a/_b/00manifest.i
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cat A/B/x
x
$ ls .hg/store/data
$ echo foo > A/B/F
$ hg add A/B/F
$ hg ci -m 'local content'
$ ls .hg/store/data
ca31988f085bfb945cb8115b78fabdee40f741aa
$ cd ..
# shallow clone from shallow
$ hgcloneshallow ssh://user@dummy/shallow shallow2 --noupdate
streaming all changes
6 files to transfer, 1008 bytes of data (no-rust !)
transferred 1008 bytes in * seconds (*/sec) (glob) (no-rust !)
8 files to transfer, 1.11 KB of data (rust !)
transferred 1.11 KB in * seconds (* */sec) (glob) (rust !)
searching for changes
no changes found
$ cd shallow2
$ hg debugrequires
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest
$ ls .hg/store/data
ca31988f085bfb945cb8115b78fabdee40f741aa
$ hg update
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat A/B/x
x
$ cd ..
# full clone from shallow
# - send stderr to /dev/null because the order of stdout/err causes
# flakiness here
$ hg clone --noupdate ssh://user@dummy/shallow full 2>/dev/null
streaming all changes
[100]
# getbundle full clone
$ printf '[server]\npreferuncompressed=False\n' >> master/.hg/hgrc
$ hgcloneshallow ssh://user@dummy/master shallow3
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets 18d955ee7ba0
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ ls shallow3/.hg/store/data
$ hg debugrequires -R shallow3/
dotencode
dirstate-v2 (dirstate-v2 !)
exp-remotefilelog-repo-req-1
fncache
generaldelta
persistent-nodemap (rust !)
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
treemanifest