remotefilelog: use raw strings when looking for variable names Keys in self.__dict__ and vars() are always str. So we need to use raw strings to ensure lookups work on Python 3. # skip-blame just r'' prefixes Differential Revision: https://phab.mercurial-scm.org/D5957

rust-cpython: binding for headrevs() This uses the core `dagops::retain_heads` to give a Rust implementation to `mercurial.dagop.headrevs`. Testing happens for now from `test-rust-ancestors.py` (for quick and minimal change), but it'd made more sense to put the binary index data elsewhere and to create a new test python module