Re: Fixes issue 1881 (cyclic dependency with beam calculations) (issue 5038042)

[n . puttock]

LGTM.

BTW, I have a few queries about stem::length:

  76   (let* ((d (ly:grob-property grob 'direction))

You don't use 'direction; is it still necessary to get it to trigger
other calculations?

  79          (beam (ly:grob-object grob 'beam)))

Why do you need to access 'beam?  AFAICT, the callback will never be
triggered on beamed notes, so it's redundant.  It also makes the last
line look like a thinko:

  82         (ly:grob-property grob 'length))))

This would be a calculation-in-progress, since you're already inside the
callback.

http://codereview.appspot.com/5038042/