Level Editor: crash when viewing, modifying, or removing particles from a level

[maxteufel]

SuperTux version: git master as of 2016-07-28 13:34 UTC+2
System information: Arch Linux, Linux 4.6.4, Clang 3.8

Expected behavior

SuperTux doesn't crash.

Actual behavior

SuperTux crashes.

Steps to reproduce actual behavior

1. Place a level using rain particles into the override-data directory recently introduced (the one where menu.stl is placed in). Example: ${buildroot}/data/levels/world2/Going_Underground.stl.
2. Open level in level editor.
3. Remove rain particles.

Additional debugging information

https://gist.github.com/maxteufel/b52115034c5b8827058124d2d5c031e3

[tobbi]

Please test the fix.

[maxteufel]

Still seems to be crashing in LayerIcon::get_zpos(), this time when removing/editing cloud particles: https://gist.github.com/maxteufel/dc7feed40866779e5a48d6071794175e

[Hume2]

I can't reproduce it.

[maxteufel]

@Hume2: it doesn't seem to be reproducible always. And it also happens with other particles (e.g. clouds).

Possibly this is related to the layer management in the editor. @tobbi suggested on our Slack that the layer could be deleted, but for some reason would still be set to a non-null value, which might cause LayerIcon::get_zpos() to crash.