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
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo z > z
$ hg commit -qAm x1
$ echo x2 > x
$ echo z2 > z
$ hg commit -qAm x2
$ hg bookmark foo
$ cd ..
# prefetch a revision w/ a sparse checkout
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
3 files to transfer, 527 bytes of data (no-zstd !)
transferred 527 bytes in * seconds (* */sec) (glob) (no-zstd !)
3 files to transfer, 534 bytes of data (zstd no-rust !)
transferred 534 bytes in * seconds (* */sec) (glob) (zstd no-rust !)
5 files to transfer, 660 bytes of data (zstd rust !)
transferred 660 bytes in * seconds (*/sec) (glob) (zstd rust !)
searching for changes
no changes found
$ cd shallow
$ printf "[extensions]\nsparse=\n" >> .hg/hgrc
$ hg debugsparse -I x
$ hg prefetch -r 0
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ hg cat -r 0 x
x
$ hg debugsparse -I z
$ hg prefetch -r 0
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ hg cat -r 0 z
z
# prefetch sparse only on pull when configured
$ printf "[remotefilelog]\npullprefetch=bookmark()\n" >> .hg/hgrc
$ hg strip tip
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/876b1317060d-b2e91d8d-backup.hg (glob)
2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg debugsparse --delete z
$ clearcache
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
updating bookmark foo
added 1 changesets with 0 changes to 0 files
new changesets 876b1317060d
(run 'hg update' to get a working copy)
prefetching file contents
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
# Dont consider filtered files when doing copy tracing
## Push an unrelated commit
$ cd ../
$ hgcloneshallow ssh://user@dummy/master shallow2
streaming all changes
3 files to transfer, 527 bytes of data (no-zstd !)
transferred 527 bytes in * seconds (*) (glob) (no-zstd !)
3 files to transfer, 534 bytes of data (zstd no-rust !)
transferred 534 bytes in * seconds (* */sec) (glob) (zstd no-rust !)
5 files to transfer, 660 bytes of data (zstd rust !)
transferred 660 bytes in * seconds (*/sec) (glob) (zstd rust !)
searching for changes
no changes found
updating to branch default
2 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)
$ cd shallow2
$ printf "[extensions]\nsparse=\n" >> .hg/hgrc
$ hg up -q 0
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ touch a
$ hg ci -Aqm a
$ hg push -q -f
## Pull the unrelated commit and rebase onto it - verify unrelated file was not
pulled
$ cd ../shallow
$ hg up -q 1
$ hg pull -q
$ hg debugsparse -I z
$ clearcache
$ hg prefetch -r '. + .^' -I x -I z
4 files fetched over 1 fetches - (4 misses, 0.00% hit ratio) over * (glob)
$ hg rebase -d 2 --keep
rebasing 1:876b1317060d foo "x2"