Add MathMLElement interface and mixins ElementCSSInlineStyle, HTMLOrForeignElement

[Philipp-M]

This aims to add the MathMLElement interface, from https://searchfox.org/mozilla-central/source/dom/webidl/MathMLElement.webidl

I noticed it used mixins that were not there yet, which are also used for the interfaces SVGElement and HTMLElement, I've added them as well and removed the redundant attributes from interfaces that inherit from these. I can keep it more focused on only the MathMLElement addition if that is desired. Was the omittance of ElementCSSInlineStyle intentional?

[daxpedda]

I noticed it used mixins that were not there yet, which are also used for the interfaces SVGElement and HTMLElement, I've added them as well and removed the redundant attributes from interfaces that inherit from these.

This is unfortunately a breaking change, so we can't do this yet.

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We prefer getting the bindings from the specification instead of from browser implementations. See https://www.w3.org/TR/MathML2/appendixe.html#dom-bindings.IDLBinding.

A changelog entry is missing as well.

[Philipp-M]

This is unfortunately a breaking change, so we can't do this yet.

What's the policy here? Accumulate more breaking changes at once?

Though I think it's a "minor breaking change" if at all, everything should be working as expected, as the methods just shift towards the parent interfaces, and coercion should do the rest, I'm not sure if that's even considered a breaking change?

We could also leave the methods on the child interfaces there, and accept the duplicated methods, so that it's not a breaking change.

We prefer getting the bindings from the specification instead of from browser implementations. See https://www.w3.org/TR/MathML2/appendixe.html#dom-bindings.IDLBinding.

Thanks for the link, I missed that (although I studied the specs as well). AFAIK this browser implementation is a subset of the specs.

The motivation for this change, is to have a mathml_element.style(), which interestingly is not in that specs. It's here though: https://www.w3.org/TR/cssom-1/#the-elementcssinlinestyle-mixin
I guess I'll just combine these then?

I think I'll just add the sub-interfaces as well, so that we have a complete and more accurate representation of MathML then?

[Philipp-M]

I'm not sure if that's even considered a breaking change

Well I guess it is, when it's used explicitly: HtmlInputElement::set_autofocus(el, true)

So that leaves this suggestion:

We could also leave the methods on the child interfaces there, and accept the duplicated methods, so that it's not a breaking change.

[daxpedda]

This is unfortunately a breaking change, so we can't do this yet.

What's the policy here? Accumulate more breaking changes at once?

I think at this point we have more then enough changes lined up for a breaking change.
There just isn't enough maintainer time available right now to actually go through with it.

See #4090.

I'm not sure if that's even considered a breaking change

Well I guess it is, when it's used explicitly: HtmlInputElement::set_autofocus(el, true)

So that leaves this suggestion:

We could also leave the methods on the child interfaces there, and accept the duplicated methods, so that it's not a breaking change.

Indeed, this sounds reasonable.
The old interfaces can be marked with [RustDeprecated].

[Philipp-M]

I've updated this to not be a breaking change anymore.

Well yet another time it turns out how messy the specification and its implementation in browsers is, e.g. https://www.w3.org/TR/MathML3/chapter2.html#fund.globatt specifies style directly, while e.g. mathElementStyle doesn't exist in the browsers I have checked (Firefox, Chrome). All the other methods seemingly not as well.
So I guess what is already in this PR, is at least compliant to the specs, and should cover all major currently used browsers...

[daxpedda]

Thank you for cleaning up the mixin interfaces!

[Philipp-M]

(force push, because CI didn't run successfully, but I don't think that failed test is related to the PR)

[daxpedda]

Thank you for the patience!