1288556 - [webvr] WebIDL Parser does not support non-cached attributes with a sequence type

Status: RESOLVED INVALID

(Core :: DOM: Core & HTML, defect)

Description

[:kip (Kearwood Gilbert)]

While implementing the WebVR 1.0 API, I encountered an error in the WebIDL parser:

    WebIDL.WebIDLError: error: A non-cached attribute cannot be of a sequence type

The WebVR 1.0 API spec defines an attribute, "activeVRDisplays" that returns a non-cached sequence:

    partial interface Navigator {
      Promise<sequence<VRDisplay>> getVRDisplays();
      readonly attribute sequence<VRDisplay> activeVRDisplays;
    };

Once we support non-cached attributes with the sequence type in our WebIDL parser, I will be able to land Bug 1284357 ([webvr] Implement Navigator.activeVRDisplays).

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

readonly attribute sequence<VRDisplay> activeVRDisplays; is not valid webidl.


http://heycam.github.io/webidl/#idl-attributes :
 The type of the attribute, after resolving typedefs, MUST NOT be a nullable or non-nullable version of any of the following types:

    a sequence type
    a dictionary
    a union type that has a nullable or non-nullable sequence type or dictionary as one of its flattened member types



I assume the spec wants FrozenArray, which we support using a bit different syntax, see Bug 1236777.

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

https://github.com/w3c/webvr/issues/61