Global and a ReadableStream reader when consuming the body

[bakulf]

"Let reader be the result of getting a reader from stream. If that threw an exception, return a new promise rejected with that exception."

In which global should this reader belong to? And what about the 'promise' created by the reader when retrieving data from the ReadableStream? I guess it's the same global of the reader.

[domenic]

In which way is this observable?

[annevk]

It's not, apart from extensions perhaps. Perhaps this should say "implementation-defined realm", but perhaps it'd fall out of fixing whatwg/webidl#135?

[annevk]

(Also relates to #730 somewhat I suppose for the creation of the empty stream.)

[bzbarsky]

It's not, apart from extensions perhaps.

The Promise involved is completely unobservable?

[annevk]

The promise returned by the undefined "transforming" operation (hopefully IDL integrates that part of the promises guide at some point) would be exposed. Presumably that would use the global of this per yet-to-be-defined IDL shorthands.

[bzbarsky]

Which "this", in this case?

[annevk]

Of the object on which the method is declared that ends up returning the promise. As the "consume body" algorithm is some internal algorithm of that object, the this object is somewhat obvious, but perhaps we'd need to make this explicit anyway somehow depending on how promises and object creation get formalized in IDL.