On Mon, Oct 10, 2016 at 7:19 PM, Jeff King <p...@peff.net> wrote: > 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
This is the perfect solution for me. Going through the delete branches runthrough also quickened the filter-branch command, and I'm left with a much more complete version of where I want to be. I would still contend that the filter-branch either doesn't work as expected, or the docs need updating to provide extra steps like you've done, because when dealing with a large repo like we have, running multiple filter-branch commands, trying different combinations is quite a time sync, when you're left with the same incorrect solution again and again. > > 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