D1502: rewriteutil: add utility function to check if we can create new unstable cset

[dlax (Denis Laxalde)]

dlax added a comment.


  > This rewriteutil.py introduced in this patch and the utility functions added in the upcoming patches exists in the evolve extension are being ported from there.
  
  Is it worth porting this alone if nothing in core makes use of this module?
  Or is there a larger plan?

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D1502

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