D3896: copies: handle case when both merge cset are not descendant of merge base

[pulkit (Pulkit Goyal)]

pulkit added a comment.


  In https://phab.mercurial-scm.org/D3896#65986, @spectral wrote:
  
  > Any updates on this?  I'm poking at updating this function in core, and not too excited to have to also modify the copy in evolve that seems to have spawned :/
  
  
  I am yet to write tests. Feel free to update the one in core, I will take care of the evolve copy.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3896

To: pulkit, #hg-reviewers
Cc: spectral, yuja, mercurial-devel