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 hardlink
$ echo "[extensions]" >> $HGRCPATH
$ echo "relink=" >> $HGRCPATH
$ fix_path() {
> tr '\\' /
> }
$ cat > arelinked.py <<EOF
> import os
> import sys
> from mercurial import (
> pycompat,
> util,
> )
> path1, path2 = sys.argv[1:3]
> if util.samefile(pycompat.fsencode(path1), pycompat.fsencode(path2)):
> print('%s == %s' % (path1, path2))
> else:
> print('%s != %s' % (path1, path2))
> EOF
create source repository
$ hg init repo
$ cd repo
$ echo a > a
$ echo b > b
$ hg ci -Am addfile
adding a
adding b
$ cat "$TESTDIR/binfile.bin" >> a
$ cat "$TESTDIR/binfile.bin" >> b
$ hg ci -Am changefiles
make another commit to create files larger than 1 KB to test
formatting of final byte count
$ cat "$TESTDIR/binfile.bin" >> a
$ cat "$TESTDIR/binfile.bin" >> b
$ hg ci -m anotherchange
don't sit forever trying to double-lock the source repo
$ hg relink .
relinking $TESTTMP/repo/.hg/store to $TESTTMP/repo/.hg/store
there is nothing to relink
Test files are read in binary mode
$ "$PYTHON" -c "open('.hg/store/data/dummy.i', 'wb').write(b'a\r\nb\n')"
$ cd ..
clone and pull to break links
$ hg clone --pull -r0 repo clone
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
new changesets 008c0c271c47
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd clone
$ hg pull -q
$ echo b >> b
$ hg ci -m changeb
created new head
$ "$PYTHON" -c "open('.hg/store/data/dummy.i', 'wb').write(b'a\nb\r\n')"
relink
#if no-reposimplestore
$ hg relink --debug --config progress.debug=true | fix_path
relinking $TESTTMP/repo/.hg/store to $TESTTMP/clone/.hg/store
tip has 2 files, estimated total number of files: 3
collecting: 00changelog.d 1/3 files (33.33%)
collecting: 00changelog.i 2/3 files (66.67%)
collecting: 00manifest.i 3/3 files (100.00%)
collecting: a.i 4/3 files (133.33%)
collecting: b.i 5/3 files (166.67%)
collecting: dummy.i 6/3 files (200.00%)
collected 6 candidate storage files
not linkable: 00changelog.d
not linkable: 00changelog.i
not linkable: 00manifest.i
pruning: data/a.i 4/6 files (66.67%)
not linkable: data/b.i
pruning: data/dummy.i 6/6 files (100.00%)
pruned down to 2 probably relinkable files
relinking: data/a.i 1/2 files (50.00%)
not linkable: data/dummy.i
relinked 1 files (1.36 KB reclaimed)
$ cd ..
check hardlinks
$ "$PYTHON" arelinked.py repo/.hg/store/data/a.i clone/.hg/store/data/a.i
repo/.hg/store/data/a.i == clone/.hg/store/data/a.i
$ "$PYTHON" arelinked.py repo/.hg/store/data/b.i clone/.hg/store/data/b.i
repo/.hg/store/data/b.i != clone/.hg/store/data/b.i
#endif