branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
$ echo '[extensions]' >> $HGRCPATH
$ echo 'strip =' >> $HGRCPATH
$ cat >findbranch.py <<EOF
> import re
> import sys
>
> head_re = re.compile(r'^#(?:(?:\\s+([A-Za-z][A-Za-z0-9_]*)(?:\\s.*)?)|(?:\\s*))$')
>
> for line in sys.stdin:
> hmatch = head_re.match(line)
> if not hmatch:
> sys.exit(1)
> if hmatch.group(1) == 'Branch':
> sys.exit(0)
> sys.exit(1)
> EOF
$ hg init a
$ cd a
$ echo "Rev 1" >rev
$ hg add rev
$ hg commit -m "No branch."
$ hg branch abranch
marked working directory as branch abranch
(branches are permanent and global, did you want a bookmark?)
$ echo "Rev 2" >rev
$ hg commit -m "With branch."
$ hg export 0 > ../r0.patch
$ hg export 1 > ../r1.patch
$ cd ..
$ if "$PYTHON" findbranch.py < r0.patch; then
> echo "Export of default branch revision has Branch header" 1>&2
> exit 1
> fi
$ if "$PYTHON" findbranch.py < r1.patch; then
> : # Do nothing
> else
> echo "Export of branch revision is missing Branch header" 1>&2
> exit 1
> fi
Make sure import still works with branch information in patches.
$ hg init b
$ cd b
$ hg import ../r0.patch
applying ../r0.patch
$ hg import ../r1.patch
applying ../r1.patch
$ cd ..
$ hg init c
$ cd c
$ hg import --exact --no-commit ../r0.patch
applying ../r0.patch
warning: can't check exact import with --no-commit
$ hg st
A rev
$ hg revert -a
forgetting rev
$ rm rev
$ hg import --exact ../r0.patch
applying ../r0.patch
$ hg import --exact ../r1.patch
applying ../r1.patch
Test --exact and patch header separators (issue3356)
$ hg strip --no-backup .
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
>>> import re
>>> p = open('../r1.patch', 'rb').read()
>>> p = re.sub(br'Parent\s+', b'Parent ', p)
>>> open('../r1-ws.patch', 'wb').write(p) and None
$ hg import --exact ../r1-ws.patch
applying ../r1-ws.patch
$ cd ..