Re: Issue 1031 in lilypond: constantly-changing input/regression/rest-collision-beam-note.ly

[lilypond]

Updates:
        Status: Started
        Owner: pnorcks

Comment #11 on issue 1031 by pnorcks: constantly-changing  
input/regression/rest-collision-beam-note.ly
http://code.google.com/p/lilypond/issues/detail?id=1031

Update:

I have discovered the culprit function call.  See below.  The result of  
this function
call is that -4 is added to the dim_cache_[Y_AXIS].offset_ field of the  
Rest grob,
resulting in a incorrect rest offset.  This call is located in
Beam::rest_collision_callback() on line 1475.  There is also a TODO, so  
I'll list it
here.

  /*
    TODO: this is dubious, because this call needs the info we're
    computing right now.
   */
  Interval rest_extent = rest->extent (common_y, Y_AXIS);


I can't work on this anymore tonight, but I'm not sure how to proceed.  Any  
hints on
how to fix this?