Correct the type of opener in Window object idl block description

[gihyeonsung]

I think we should correct the type of attribute opener from any to WindowProxy? since the current idl block is not describing the type of its definition concretely.

The opener getter steps are:

1. Let current be this's browsing context.

2. If current is null, then return null.

3. If current's disowned is true, then return null.

4. If current's opener browsing context is null, then return null.

5. Return current's opener browsing context's WindowProxy object.

The opener setter steps are:

1. If the given value is null and this's browsing context is non-null, then set this's browsing context's disowned to true.

2 .If the given value is non-null, then return ? OrdinaryDefineOwnProperty(this, "opener", { [[Value]]: the given value, [[Writable]]: true, [[Enumerable]]: true, [[Configurable]]: true }).

[saschanaz]

e690fe8 changed it from WindowProxy to any, citing https://www.w3.org/Bugs/Public/show_bug.cgi?id=21946.

But I'm not sure it holds in 2022 when both WebKit and Blink has WindowProxy/Window:

• https://searchfox.org/wubkat/rev/3dde8827051a9b051f6614f5956ee9ca6e1cbc31/Source/WebCore/page/DOMWindow.idl#73
• https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/frame/window.idl;l=63;drc=a1ad6e99c18b78d26e5b67e0ad8e381a7a844bc7

@domenic, thoughts?

[saschanaz]

Oh, actually both WebKit and Blink has a custom setter behavior where random things are allowed to be assigned. Probably too dangerous to change that then.

[mathe42]

Note that there is https://github.com/web-platform-tests/wpt/blob/master/html/browsers/windows/auxiliary-browsing-contexts/resources/opener-setter.html an explicit test to check if you can set it to a string,

[domenic]

WindowProxy is not a defined IDL type, so while implementations may use it for some sort of codegen, I don't think it makes sense to use it in specs.

[saschanaz]

That's an interesting argument as there are already several attributes that uses WindowProxy in the spec. 👀