Attempt to remove implied-document definition

[dtapuska]

@bzbarsky has raised concerns a few times about the lack of formal definition of a task's document. The definition comes from the implied-document which is relatively handwavy.

Can we brainstorm some ideas how we can better formalize this?

For example I'm wondering if we can introduce a "queue a document task" and then we can change the call sites to "queue a document task given element's document". And then that could take the event loop from the document so we wouldn't need to use the definition of implied event loop either. Now that doesn't cover all the cases but would be a fair number of them.

[annevk]

That sounds great to me.

[domenic]

Yes, this would be lovely. It's just a ton of work. I count 202 uses of "queue a task" in HTML alone, not to mention the rest of the ecosystem. That said, @dtapuska has done heroic things before... and incremental progress is totally possible, i.e. we keep using implied document as a fallback until all call sites are updated.

I'm unsure whether we should introduce a new "queue a document task" + "queue a document microtask" or just reuse "queue a task" and add a semi-optional parameter. (I.e., it's mandatory in window event loops.) It's worth thinking about how this would impact cases that are polymorphic over event loops. There aren't many of these; maybe just BroadcastChannel's postMessage().

Anyway I think the right thing to do is figure out what the various call sites look like. Ideas:

Queue a task on the X task source, with document doc, to run the following steps:

Queue a task on the X task source of event loop, with document doc, to run the following steps:

Queue a task on the X task source of event loop to run the following steps. If event loop is a window event loop, this must be done with document doc.

(Only valid in worker event loops.) Queue a task on the X task source to run the following steps:

[dtapuska]

I think we should reopen this issue until they all land no? Not sure what the magic was that closed it in github but it didn't have closes in the commit msg I don't think.

[domenic]

Ah, I guess it was in the pull request description. Thanks for the heads-up.