D3975: mergetool: warn if ui.merge points to nonexistent tool

[yuja (Yuya Nishihara)]

yuja added a comment.


  Queued, thanks.
  
  >   $ hg merge -y -r 2 --config ui.merge=missingbinary
  > 
  > +  couldn't find merge tool missingbinary (for pattern f)
  
  Nit: "for pattern f" seems misleading since `ui.merge` is not defined per
  filename pattern.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3975

To: martinvonz, #hg-reviewers, lothiraldan
Cc: yuja, mercurial-devel