Re: Issue 818 in lilypond: Bus error when adding Instrument_name_engraver to StaffGroup and outputting MIDI.

[lilypond]

Updates:
        Status: Started
        Owner: n.puttock
        Labels: Patch

Comment #21 on issue 818 by n.puttock: Bus error when adding  
Instrument_name_engraver to StaffGroup and outputting MIDI.
http://code.google.com/p/lilypond/issues/detail?id=818

This appears to have been introduced in 2.8.8, but annoyingly there's no  
tag for this release (or 2.8.7).

I've posted a patch which prevents this segfault (verified in GUB builds  
for linux-x86, linux-64 and mingw), but am none the wiser why it works.

I can't see anything untoward using valgrind, and there's no significant  
difference in vtable pointers between working/broken builds.