Add shader_cache_dir_valid check to _save_to_cache

[jsjtxietian]

Fixes #87079

Alternatively one could argue that we should add the check to the call site instead of inside the function, but I think add a protection inside it is harmless and prevent future mistakes.

[akien-mga]

Alternatively one could argue that we should add the check to the call site instead of inside the function, but I think add a protection inside it is harmless and prevent future mistakes.

I think it might need to do both.

Usually we would use ERR_FAIL_COND if the contract of a function is not respected. Here, I think _save_to_cache should never be called if there's no valid shader cache dir, so it should raise an error.

And then the call site where it's not properly doing the check should be changed. _save_to_cache is called in three files, and two of them properly check:

if (shader_cache_dir_valid) {
	_save_to_cache(p_version);
}

But that check is missing in shader_gles3.h:

Version::Specialization *spec = version->variants[p_variant].lookup_ptr(p_specialization);
if (!spec) {
	if (false) {
		// Queue load this specialization and use defaults in the meantime (TODO)

		spec = version->variants[p_variant].lookup_ptr(specialization_default_mask);
	} else {
		// Compile on the spot
		Version::Specialization s;
		_compile_specialization(s, p_variant, version, p_specialization);
		version->variants[p_variant].insert(p_specialization, s);
		spec = version->variants[p_variant].lookup_ptr(p_specialization);
		_save_to_cache(version);
	}

[jsjtxietian]

But that check is missing in shader_gles3.h

Yes I noticed that too, you are right, it need to do both, an if guard at the call site and ERR_FAIL_COND in the function .

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 4.2.2.

[SinaZK]

Could we see this on 4.1.5 too? We have a released mobile game using 4.1 and we need to get rid of many annoying errors when shader cache is off in the project settings.