Re: [Denemo-devel] denemo causing session crash

[Richard Shann]

On Sun, 2018-04-22 at 19:30 -0400, Bric wrote:
> > On April 21, 2018 at 8:53 PM Bric <address@hidden> wrote: 
> > 
> > [...]
> 
> The following extra detail could be relevant to  your development and
> tweaking, though i'm not 100% sure it's a denemo "mis-behavioral":
> 
> It crashed on me twice on lilypond syntax error, during Print View
> refresh.

"It crashed"? what did? what were the symptoms?

>   There is a purple error message in the preview window, at the top,
> saying the cursor was probably placed where the error is, in the
> editor.

That means that the LilyPond process emitted some error or warning
message with a line and column reference to the LilyPond syntax, which
Denemo then tried to tie back to the place in the Denemo Display
("editor") which corresponded to that bit of syntax. This fails if the
line/col reference is not to something inside the music but in the
headers etc.


> 
> My particular syntax errors were tying two notes [...] which were not
> the same pitches [...]


This will not cause LilyPond any problem (it happens a lot while
editing), LilyPond will issue a warning (and hence Denemo will try to
position the cursor) and not draw a tie.

> 
> i THINK i've seen it crash before on lilypond syntax... 

You can get LilyPond to crash on syntax, but it would not be able to
cause Denemo to crash, they are completely different Unix processes -
if your O/S or hardware is faulty it might cause a system crash...
All that Denemo is doing is its usual cycling round waiting for the O/S
to signal that the LilyPond process has terminated (and, in that case
what it said) or if you have pressed a key or clicked a mouse or played
on your MIDI controller. It's doing that all the time, so unless the
LilyPond process blew the whole system up there is nothing special
going on.
The worst that can happen is the LilyPond hangs and then Denemo
continues waiting for it to finish. You can kill the LilyPond off via
the progress bar and/or by starting another typeset.

Richard