git: make dirstate status() respect matcher As with other changes in this stack, we appear to have been getting lucky in the past. An upcoming change behaved _very_ oddly without this fix. Differential Revision: https://phab.mercurial-scm.org/D8997

git: fix up dirstate use of index This was super-broken before, and somehow none of the existing attempts to use this code tripped on the defects here. Sigh. Differential Revision: https://phab.mercurial-scm.org/D8996

git: correctly handle "nothing changed" commits I guess localrepo.commit() actually returns an Optional[node], which is a bit of a surprise to me. Differential Revision: https://phab.mercurial-scm.org/D8995

localrepo: use functools.wraps() in unfilteredmethod decorator This makes it easier to figure out what function you're holding on to when doing printf-style debugging. Differential Revision: https://phab.mercurial-scm.org/D8994

git: actually copy treemanifest instances in .copy() (issue6398) The implementation here is so simple I honestly have no idea why I didn't do it at the time. Hopefully there's not some nuance past-me forgot to write down. Differential Revision: https://phab.mercurial-scm.org/D8993

git: restore basic functionality after b3040b6739ce We don't yet have a formal interface for the changelog, but it's mostly specified. Sadly, b3040b6739ce added a semi-private pseudo-enum that we need to cope with, so it's probably high time that someone (me?) attempts to define that interface to prevent future backsliding. Differential Revision: https://phab.mercurial-scm.org/D8992

git: convert tz offset to int (issue6359) Differential Revision: https://phab.mercurial-scm.org/D8991