feat: support () type in typegen

[nedsalk]

While implementing #2070 I came across an issue with call-test-contract's foobar function that takes in an empty () type. Typegen couldn't handle it and was throwing so I implemented the logic for supporting () types.
Now, empty inputs are ignored in typegen. This corresponds to how we're encoding empty arguments during runtime - we ignore them. I added tests to verify this runtime behavior as well.

[arboleya]

Now, functions that take in an empty type mandate passing undefined into them:

const fn = contract.functions.foobar(undefined); // InvokeFunction<[value: undefined], ...>

Oof. It's a tough one - I'm not sure I can handle it. 😅

[arboleya]

These feel ok:

contract.functions.empty().call();
contract.functions.value_then_empty(35).call();

These do not:

contract.functions.empty_then_value(35).call();
contract.functions.value_then_empty_then_value(35, 35).call();

I believe the expected usage would be somewhat similar to the following:

contract.functions.empty_then_value(null, 35).call();
contract.functions.value_then_empty_then_value(35, null, 35).call();

EDIT: If empty types are always ignored, should they exist in Sway and compile successfully? Do you know their purpose?

[nedsalk]

@arboleya I don't know the purpose of the empty types.

I agree with you that the expected behavior should be the one you mentioned for all cases. I didn't implement it like that because it required changes to the runtime behavior of the ABI coder, because currently the abi-coder also removes the empty types and fails if you provide it a value like in your proposal.
I didn't go down that route because of the critical work going on with the new ABI encoding. These edge case runtime tests I added will have to be green for the new encoding as well and maybe we'll have to change the runtime behavior for empty types due to them. Thus, IMO we should handle these oddities in a separate PR once the dust settles. What do you think?

[arboleya]

Please create a detailed follow-up issue with the adjustments you mentioned on the ABI Coder.

Using our tests to dogfood Typegen was a nice touch! 👏 🚀

I hope this is also beneficial for browser testing.

[petertonysmith94]

Looks wonderful 🚢

[github-actions]

Coverage Report:

Lines	Branches	Functions	Statements
79.34%(+0.02%)	69.3%(+0%)	77.38%(+0.06%)	79.49%(+0.02%)

Changed Files:

Ok	File (✨=New File)	Lines	Branches	Functions	Statements
✅	✨ packages/abi-typegen/src/abi/types/EmptyType.ts	100% (+100%)	100% (+100%)	100% (+100%)	100% (+100%)