[4.5 beta 1] Referencing NORMAL in the light function of any custom shader causes a huge shader compilation error

[antourenein]

Tested versions

-Reproducible in 4.5 beta 1
-Not reproducible in 4.5 dev 5

System information

Godot v4.5.beta1 - Windows 11 (build 26100) - Multi-window, 2 monitors - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3060 Laptop GPU (NVIDIA; 32.0.15.7652) - 12th Gen Intel(R) Core(TM) i7-12700H (20 threads) - 63.74 GiB memory

Issue description

Creating any custom spatial shader that references the built-in NORMAL seems to cause a shader compilation error in the general shader that wraps up the custom shaders internally.

Something as simple as

shader_type spatial;
render_mode blend_mix;

void light() {
	DIFFUSE_LIGHT = NORMAL;
}

causes a huge 8k line shader compilation error in the output that even slows down the editor itself.

Here is a copy of the full error in the output:
normal-error-log.txt

Steps to reproduce

• Open the MRP
• Find the Material in the Surface Material Override of the main MeshInstance3D scene
• Edit the shader and remove the comment from the //DIFFUSE_LIGHT = NORMAL; line
• Watch the editor spam the compilation error.

Minimal reproduction project (MRP)

LightShaderErrorMRP.zip

[beicause]

Looks like:

• [4.5.beta1] Spatial shader compilation failed when reading NORMAL in light() in Forward+ renderer #107590

It has been fixed in master but not included in beta1.

[AThousandShips]

Indeed duplicate of that issue, will be in beta 2