Remove convert() utility method

[KoBeWi]

This method simply calls the constructor of the target type. It might be useful e.g. if you want to pass the type as parameter to have some generic conversion function, but it's some weird edge case and it's unsafe. You can achieve the same using a series of ifs..

Closes #5523
Closes #65919

[MikeSchulze]

PLEASE don't remove the convert function, i need it too!
To implement this is very anoing and will explode in a unreadable function with tons of if/else cases

[fire]

I see some opposition. What are the weird edge cases and why is it unsafe?

[KoBeWi]

It is unsafe, because you can put any type (or just any integer) as the second argument, but the conversion might be unsupported. The function doesn't provide type hint and may result in an error.

As for edge-cases, I referred to the use-case of this function. It's just very niche and if you need it, you can use match or a series of if else, which also gives you more control over what happens under the hood.

That said, I'm ok if the function is kept, but then we need to properly fix the linked issues somehow.

[fire]

properly fix the linked issues

I have a feeling if we the contributor of the engine can't do write a correct convert function correctly in the engine. We can't expect the user-developers of Godot Engine to do it correctly either.

[KoBeWi]

Eh but GDScript implementation looks like this

func convert(variant, type):
	match type:
		TYPE_INT:
			return variant as int
		TYPE_FLOAT
			return variant as float
	etc.

The C++ implementation just uses some convoluted built-in logic, so it's more difficult to get right.

[Mickeon]

The fact that convert() does a strict conversion strikes as odd to me. The "in the best way possible" of the documentation feels misleading if, for example, a Color can't be converted into a PackedFloat32Array of size 4, as outstandingly situational as that may be. I wonder if it would be reasonable to upgrade this method instead of outright removing it. It can't even handle String conversion anymore.

[MikeSchulze]

I see it the same way, having a convert method makes perfect sense.
For unsupported conversion it can simply return an error.

[aaronfranke]

For my uses, I want a loose conversion. I opened #70080 to accomplish this. I think that it would be a good idea to remove this old utility method and replace it with the superior method I propose in #70080. It uses the same logic as the internal Variant operators, so it is able to easily convert many things to many other things.

[reduz]

Also against removing this. Its not unsafe because it ensures you get the type no matter the input. If you want the safe version, you just use a cast.