676     if not heads or heads == [nullid]:

   676     if not heads or heads == [nullid]:

   677         return []

   677         return []

   678     # The logic operated on revisions, convert arguments early for convenience

   678     # The logic operated on revisions, convert arguments early for convenience

   679     new_heads = set(rev(n) for n in heads if n != nullid)

   679     new_heads = set(rev(n) for n in heads if n != nullid)

   680     roots = [rev(n) for n in roots]

   680     roots = [rev(n) for n in roots]

   683     # compute the area we need to remove

   681     # compute the area we need to remove

   684     affected_zone = repo.revs("(%ld::%ld)", roots, new_heads)

   682     affected_zone = repo.revs("(%ld::%ld)", roots, new_heads)

   685     # heads in the area are no longer heads

   683     # heads in the area are no longer heads

   686     new_heads.difference_update(affected_zone)

   684     new_heads.difference_update(affected_zone)

   687     # revisions in the area have children outside of it,

   685     # revisions in the area have children outside of it,