D821: unamend: move fb extension unamend to core

[durham (Durham Goode)]

durham accepted this revision.
durham added a comment.


  Overall looks good to me.  My one comment is probably not enough to block this going in.

INLINE COMMENTS

> uncommit.py:260
> +    prednode = markers[0].prednode()
> +    predctx = unfi[prednode]
> +

Might be worth doing the predecessor check in the lock as well, since the result of this verification could technically change between now and when the lock is taken.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D821

To: pulkit, #hg-reviewers, durham
Cc: ryanmce, singhsrb, durham, mercurial-devel