[css-houdini-drafts] [css-typed-om] TypedOM uses WebIDL setters with non-undefined return values (#1142)

emilio has just created a new issue for https://github.com/w3c/css-houdini-drafts:

== [css-typed-om] TypedOM uses WebIDL setters with non-undefined return values ==
`CSSTransformValue` has:

```idl
setter CSSTransformComponent (unsigned long index, CSSTransformComponent val);
```

`CSSUnparsedValue` has similar code. That interestingly caused issues (warnings) on the Gecko codegen ([bug 1981764](https://bugzil.la/1981764)).

The return value gets ignored in other implementations as well, and I think it doesn't make sense, since the behavior of the assignment operator is to return the right-hand-side, so if you were to return something else from webidl it'd be... odd?

I don't know how/if you can get the actual native function for the setter to call it directly and check its return value, I don't _think_ you can... So is the return value of a setter observable in any way?

I think this is most likely an oversight, WebIDL `setter`s should probably all return `undefined`, and TypedOM should use that... @tabatkins @andruud, am I missing something?

cc @saschanaz @janvarga

Please view or discuss this issue at https://github.com/w3c/css-houdini-drafts/issues/1142 using your GitHub account


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Received on Friday, 8 August 2025 09:06:06 UTC