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

[yuja (Yuya Nishihara)]

yuja added a comment.


  Can you add some tests that make both `dirtyc1` and `dirtyc2` set, and
  trigger copy tracing?
  
  > Since we can have both dirtyc1, and dirtyc2 true, I am not sure whether
  >  this else should be turned into it's own if statement?
  
  No idea. I doubt if the current copy tracing can handle such cases. From
  my vague memory, the current algorithm relies on the fact that the pseudo
  `base` revision exists in between the `c1` and the `c2`.

REPOSITORY
  rHG Mercurial

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

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