Strange space between beam and slur

[Lukas-Fabian Moser]

Folks,

while engraving a Bach chorale, I stumbled over an overlarge space 
between a slur and a beam. After a happy hour of trying to boil the 
problem down to a minimal example, I arrived at:

\version "2.19.39"

\new Staff
<<
  {
    R1
    a''8( b'' b'' a'')
  } \\ {
    r4
  }
>>

This leads to the attached image.

The bug (I venture to call it such) first appeared in 2.19.39. (I 
couldn't do a true bisect on the git repository because for older 
versions, "make"ing LilyPond aborted with complaints about illegal 
casts, so I resorted to manually bisecting through the unstable releases 
- another happy half an hour :-).)

Finally, bisecting between release/2.19.38-1 and release/2.19.39-1 yields:


87eb2f9fe1be3a532675fe4b7322bbba5a60ba5c is the first bad commit
commit 87eb2f9fe1be3a532675fe4b7322bbba5a60ba5c
Author: Carl Sorensen <address@hidden>
Date:   Sat Mar 5 21:30:46 2016 -0700

    Use a negative value of overdone_noteheads to shrink the head slightly

:040000 040000 3cfab39db244953418b511ac3804bc4a3f7e1450 
224010f6fcca97776b8f38c5e33ed1c32be9e8f4 M    input
:040000 040000 86018b9a41eb153e364f218eb9c2e9693c142d24 
9a7a328516784fe2aefadcbcf344e10af1aefff0 M    mf

That's about as much as I can contribute, I guess. Does anybody have an 
idea what precisely is causing the problem?

Best
Lukas

image-1.png
Description: PNG image