Script that calls OptionButton add_separator() with no arguments crashes Godot on POT generation

[SanteriLoitomaa]

Tested versions

• Found on v4.2.1.stable.official [b09f793]

System information

Godot v4.2.1.stable - Windows 10.0.19045 - GLES3 (Compatibility) - NVIDIA GeForce GTX 1650 (NVIDIA; 31.0.15.5123) - AMD Ryzen 5 3550H with Radeon Vega Mobile Gfx (8 Threads)

Issue description

A script that calls OptionButton add_separator() with no arguments crashes Godot on POT generation with the following error message:

ERROR: FATAL: Index p_index = 0 is out of bounds (size() = 0).
   at: get (./core/templates/cowdata.h:158)

Using add_separator("") works fine, making me think that there is something in the code that expects there to be a string even when it is not a required argument. The problem may thus be more widespread and actually affect all functions that expect a string as an argument but don't outright require it.

Steps to reproduce

1. Add the following script to your Project Settings > Localization > POT Generation > Files with translation strings:

extends OptionButton


func _ready():
	add_separator()

2. Generate POT
3. Crash

Minimal reproduction project (MRP)

POTGenCrash.zip
Generating POT with Crash.gd included will crash Godot.
Generating POT with only NoCrash.gd will not crash Godot.

[dalexeev]

Not reproducible in 4.3 dev, fixed by #86471.

Thanks for reporting the bug nonetheless!