Tagged arrays not being initialized correctly with `...` syntax

[xunder-matth]

Compiler version: Pawn compiler 3.10.11 downloaded from open.mp v1.4.0.2779 server build

When initializing an array using a tagged enum size with the ellipsis (...) syntax, the array is not being properly initialized. Specifically, elements after the first one are set to 0 instead of being repeated as expected.

MVCE:

enum e_TEST_ENUM {
	TEST_ITEM_1,
	TEST_ITEM_2,
	TEST_ITEM_3,
	TEST_ITEM_4
};

new NotWorking[e_TEST_ENUM] = { 5, ... };

const TEST_ENUM_SIZE = _:e_TEST_ENUM;
new Working[e_TEST_ENUM:TEST_ENUM_SIZE] = { 5, ... };

#assert sizeof NotWorking == sizeof Working

main() {
	for(new i = 0; i != sizeof NotWorking; ++ i) {
		printf("%d, %d", NotWorking[e_TEST_ENUM:i], Working[e_TEST_ENUM:i]);
	}
}

Output:

5, 5  
0, 5  
0, 5  
0, 5  

Expected behavior:

5, 5  
5, 5  
5, 5  
5, 5  

[Y-Less]

Consider this small variation:

enum e_TEST_ENUM {
	TEST_ITEM_1,
	TEST_ITEM_2,
	Float:TEST_ITEM_3,
	bool:TEST_ITEM_4
};

new NotWorking[e_TEST_ENUM] = { 5, ... };

Should that produce 5, 6, 7.0, !!8?

The enum syntax used here is the syntax for approximating structures, and each element is independent. In your second example you're tricked the compiler in to stripping the information about the tags of each separate element and just made a normal array with a tagged index.

Basically this:

enum e_TEST_ENUM {
	TEST_ITEM_1,
	TEST_ITEM_2,
	TEST_ITEM_3,
	TEST_ITEM_4
};

new NotWorking[e_TEST_ENUM] = { 5, ... };

And this:

const
	e_TEST_ENUM:TEST_ITEM_1 = e_TEST_ENUM:0,
	e_TEST_ENUM:TEST_ITEM_2 = e_TEST_ENUM:1,
	e_TEST_ENUM:TEST_ITEM_3 = e_TEST_ENUM:2,
	e_TEST_ENUM:TEST_ITEM_4 = e_TEST_ENUM:3,
	e_TEST_ENUM:e_TEST_ENUM = e_TEST_ENUM:4;

new Working[e_TEST_ENUM] = { 5, ... };

Are subtly different. The former has per-element tag information, the latter doesn't. Because of this per-element information they're handled separately in everything.

There is one thing you could try:

enum e_TEST_ENUM: {
	TEST_ITEM_1,
	TEST_ITEM_2,
	TEST_ITEM_3,
	TEST_ITEM_4,
	TEST_ENUM_SIZE
};

new MaybeWorking[TEST_ENUM_SIZE] = { 5, ... };

That's an anonymous enum with the e_TEST_ENUM tag, rather than an enum named e_TEST_ENUM (notice the : before {). It's a subtle change, but might work (I genuinely can't remember).

[xunder-matth]

enum e_TEST_ENUM: {
	TEST_ITEM_1,
	TEST_ITEM_2,
	TEST_ITEM_3,
	TEST_ITEM_4,
	TEST_ENUM_SIZE
};

new MaybeWorking[TEST_ENUM_SIZE] = { 5, ... };

This method works as I initially expected.

However, the open.mp standard library heavily uses tags, which, if I'm not mistaken, will produce the same kind of issue. For example:

new WeaponPrices[MAX_WEAPONS] = { 100, 200, ... };

This will populate all slots with zeros (except for slots 0 and 1). This can be problematic when trying to initialize an array with default values.