On Mon, Oct 10, 2016 at 05:12:25PM +0100, Seaders Oloinsigh wrote:
> Due to the structure of this repo, it looks like there are some
> branches that never had anything to do with the android/ subdirectory,
> so they're not getting wiped out. My branch is in a better state to
> how I want it, but still, if I run your suggestion,
> [...]
Hmm. Yeah, I think this is an artifact of the way that filter-branch
works with pathspec limiting. It keeps a mapping of commits that it has
rewritten (including ones that were rewritten only because their
ancestors were), and realizes that a branch ref needs updated when the
commit it points to was rewritten.
But if we don't touch _any_ commits in the history reachable from a
branch (because they didn't even show up in our pathspec-limited
rev-list), then it doesn't realize we touched the branch's history at
all.
I agree that the right outcome is for it to delete those branches
entirely. I suspect the fix would be pretty tricky, though.
In the meantime, I think you can work around it by either:
1. Make a pass beforehand for refs that do not touch your desired
paths at all, like:
path=android ;# or whatever
git for-each-ref --format='%(refname)' |
while read ref; do
if test "$(git rev-list --count "$ref" -- "$path")" = 0; then
echo "delete $ref"
fi
done |
git update-ref --stdin
and then filter what's left:
git filter-branch --subdirectory-filter $path -- --all
or
2. Do the filter-branch, and because you know you specified --all and
that your filters would touch all histories, any ref which _wasn't_
touched can be deleted. That list is anything which didn't get a
backup entry in refs/original. So something like:
git for-each-ref --format='%(refname)' |
perl -lne 'print $1 if m{^refs/original/(.*)}' >backups
git for-each-ref --format='%(refname)' |
grep -v ^refs/original >refs
comm -23 refs backups |
sed "s/^/delete /" |
git update-ref --stdin
-Peff