D2596: state: raise ProgrammingError if an invalid key is being accessed

[pulkit (Pulkit Goyal)]

pulkit added a comment.


  In https://phab.mercurial-scm.org/D2596#42672, @durin42 wrote:
  
  > Hmm, really? Do any states have optional entries that would make this awkward?
  
  
  Nope, but I wanted to be safe here raising a ProgrammingError instead of KeyError.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2596

To: pulkit, #hg-reviewers
Cc: durin42, mercurial-devel