view hgext/git/TODO.md @ 45425:f7e293e0475f

rewriteutil: also consider pending obsoletes when updating hashes in messages

Phabricator builds up the replacement commits and mapping in a single
transaction, and then finalizes everything once the commits have been rewritten.
That's too late when trying to update the messages for those commits.

I'm a little concerned that this isn't a generic enough interface, since it
doesn't mimic the list of list return of `obsutil.successorssets()`.  But this
is the type of mapping that phabricator maintains, and I don't think the methods
that would be interested in calling this need to worry about split and
divergence.  We can fix that later if the need arises.

Differential Revision: https://phab.mercurial-scm.org/D8949

Octopus Merge Support
=====================

This will be moderately complicated, as we'll need to synthesize phony
changeset entries to explode the octopus into "revisions" that only
have two parents each. For today, we can probably just do something like

    aaaaaaaaaaaaaaaaaaXX{20 bytes of exploded node's hex sha}

where XX is a counter (so we could have as many as 255 parents in a
git commit - more than I think we'd ever see.) That means that we can
install some check in this extension to disallow checking out or
otherwise interacting with the `aaaaaaaaaaaaaaaaaa` revisions.


Interface Creation
====================

We at least need an interface definition for `changelog` in core that
this extension can satisfy, and again for `basicstore`.


Reason About Locking
====================

We should spend some time thinking hard about locking, especially on
.git/index etc. We're probably adequately locking the _git_
repository, but may not have enough locking correctness in places
where hg does locking that git isn't aware of (notably the working
copy, which I believe Git does not lock.)