#5562 crash: Assertion `!is_empty ()' failed.

[Werner LEMBERG]

[cf7be2a0d5093fb890083d09c1e320d8e06d3991]

This small input file

{
  \omit Flag
  \omit NoteHead

  b( b)
}

makes lilypond crash with

../flower/include/interval.hh:227:
  T Interval_t<T>::center() const [with T = double]:
  Assertion `!is_empty ()' failed.

https://codereview.appspot.com/546970043

[Malte Meyn]

You can even omit the \omit Flag to reproduce that bug (if it is one, see my comment at issue 5561)

[Anonymous]

Passes make. make check and a full make doc

[Anonymous]

Patch on countdown for Oct 5th

[Anonymous]

Patch counted down - please push

[Malte Meyn]

commit 7e6a95662522ef586614bf547539b2b05e4afb23
Author: Malte Meyn lilypond@maltemeyn.de
Date: Mon Sep 30 16:58:59 2019 +0200

Issue 5561/5562: slurs work without NoteHead stencil

While searching for slur configurations LilyPond crashed on NoteHeads
without stencil because of empty extents. Also, when there cannot be
found a viable slur config, this is reported as a warning rather than a
failed assertion.

This fixes also [#5561].