check-commit: allow underbars in cffi_-prefix function names It seems reasonable to give cffi functions slightly more verbose names in some circumstances, given the way they interface with C.

bundlerepo: add support for treemanifests in cg3 bundles This is a little messier than I'd like, and I'll probably come back and do some more refactoring later, but as it is this unblocks narrowhg. An alternative approach (which I may do as part of the mentioned refactoring) would be to construct *all* dirlog instances up front, so that we don't have to keep track of the linkmapper method. This would avoid a reference cycle between the bundlemanifest and the bundlerepository, but I was hesitant to do all the work up front like that. With this change, it's possible to do 'hg incoming' and 'hg pull' from bundles in .hg/strip-backup in a treemanifest repository. Sadly, this doesn't make it possible to 'hg clone' one of those (if you do 'hg strip 0'), because the cg3 in the bundle gets written without a treemanifest flag. Since that's going to be an involved refactor in a different part of the code (which I *suspect* won't touch any of the code I've just written here), let's leave it as an idea for Later.

auditvfs: forward options property from nested vfs This was breaking my ability to use treemanifests in bundlerepos, and was deeply mysterious. We should probably just make the options property a formal part of the vfs API, and make it a required construction parameter. Sadly, I don't have time to dive into that refactor right now.

bundlerepo: use supportedincomingversions instead of allsupportedversions Since bundlerepo is really a pull-like operation, this is the correct method to use here.

bundlerepo: introduce method to find file starts and use it This moves us to the modern iter() technique instead of the `while True` pattern since it's easy. Factored out as a function because I'm about to need this in a second place.

bundlerevlog: use for loop over iterator instead of while True The iter() builtin has a neat pattern where you give it a callable of no arguments and a sentinel value, and you can then loop over the function calls like a normal iterator. This cleans up the code a little.

bundlerepo: use for loop over iterator instead of while True The iter() builtin has a neat pattern where you give it a callable of no arguments and a sentinel value, and you can then loop over the function calls like a normal iterator. This cleans up the code a little.