Throw behaviour of calling setter without argument

[shannonbooth]

WPT https://github.com/web-platform-tests/wpt/blob/9b1f66c6fa9f6bc4e9abe3346d4069be7964b10e/wasm/jsapi/global/value-get-set.any.js#L135

Tests that calling a setter without any arguments should throw a TypeError, which all browsers implement. This might be me missing it - but this does not seem to be specified anywhere.

The getter in question is defined in IDL: https://webassembly.github.io/spec/js-api/#global

IDL attribute setter defines the steps such that undefined should be passed rather than throwing:

1. Let V be undefined.
2. If any arguments were passed, then set V to the value of the first argument passed.

And https://webassembly.github.io/spec/js-api/#dom-global-value does not seem like it should result in a throw in this scenario.

Maybe the getter in the spec needs to be special cased for this scenario?

[Ms2ger]

This test was correct when I wrote it back in 2018, and remained so until the webidl spec changed in 2025: whatwg/webidl#1497 whatwg/webidl#1498. (cc @arai-a fyi)

It's not workable to change the setter on the wasm side, because we can't tell the difference between global.value = undefined (which we definitely need to support) and setter.call(global).

I think we can assume nobody relies on this particular quirk, and flip the expectation in the test. I'd be happy to review a PR to that effect.

[shannonbooth]

Oh, thanks, sorry I had missed that this had changed in the WebIDL specification.

I have raised web-platform-tests/wpt#57755