Project with extra large icon triggers X11 error: BadLength (poly request too large or internal Xlib length error)

[akien-mga]

Godot version:
3.0.3-stable and current master branch (80f7eac)

OS/device including version:
Linux (Mageia 6 x86_64) with X11 1.19.5
Nvidia GTX 670MX

Issue description:
The Godot jam entry Meltdown Hydrocooler Force by @DarrellWulff doesn't run on Linux X11 64-bit. The (custom) splash screen is shown, and then freezes on the splash screen with this error in the terminal:

OpenGL ES 3.0 Renderer: GeForce GTX 670MX/PCIe/SSE2
Boot splash path: res://DWLogo.png
X Error of failed request:  BadLength (poly request too large or internal Xlib length error)
  Major opcode of failed request:  18 (X_ChangeProperty)
  Serial number of failed request:  242
  Current serial number in output stream:  242

This could be reproduced by another user too: https://itch.io/post/448272

Source code for the game is available, and I could confirm that the same issue happens when running from the source code with both Godot 3.0.3-stable and the current master branch.

Steps to reproduce:

• Download https://github.com/DarrellWulff/Meltdown-Hydrocooler-Force-Godot-Game-Jam-
• Open it in the editor to get assets imported
• Try to run the main scene

Minimal reproduction project:
See above.

[akien-mga]

CC @hpvb as X11 guru always up for a challenge :P

[akien-mga]

The issue happens because of this line: https://github.com/DarrellWulff/Meltdown-Hydrocooler-Force-Godot-Game-Jam-/blob/14aaba438560cf9cc1556769529e3946398dec28/project.godot#L18

That project tries to load a 3072x2048 PNG (!) as project icon (!!), which X11 likely doesn't like: https://raw.githubusercontent.com/DarrellWulff/Meltdown-Hydrocooler-Force-Godot-Game-Jam-/master/UI/MainTitle.png

We likely need to add some icon validation logic on X11 to prevent such issues (might also be relevant on other platforms).

[hpvb]

Hmm, yeah, I don't think this should work, but we obviously also shouldn't just crash. I'll try to fix this.