[Denemo-devel] Grace Note hints broken in 1.1.4

[Richard Shann]

The grace note hints command (which allows LilyPond to typeset music
with grace notes at repeat bars etc) is broken in 1.1.4, it works in
1.1.2.

Eloi - this is a good opportunity to put your automated testing system
to a good use, tracking down this regression. I have added a file
tests/integration-data/grace-note-hints.denemo to git.
It should be loaded and the scheme

(d-InstallGraceNoteHints)
(d-SaveAs Denemo-test-output-file)
(d-Quit)

executed - (Denemo-test-output-file needs defining to something suitable
for diffing with the expected output).
This is currently generating a broken file, but 1.1.2 generates the
correct output.

Meanwhile:
I have started investigating by hand and I think I see the source of the
problem:
The command InsertBlankWholeNote which is in 

Notes/Rests->Rest Insertion->Insert a non-printing 𝄻 rest

fails when executed from the menu, and when executed from the scheme
CLI, but it works correctly when executed from the Command Center (there
is a box in the command center to execute the selected command).

When it fails it inserts two blank whole note rests instead of one.

I guess this is related to the changes which are causing the crash. I'll
also commit a temporary guard against the crash in view.c as I don't
want people to lose data if they are using the latest git.

Richard