[whatwg] DataTransfer.files tri-specification conflict

David Flanagan david at davidflanagan.com
Sat Feb 19 23:52:24 PST 2011

1) HTML5 says this about DataTransfer.files:

> The files attribute must return a live FileList sequence consisting of File objects representing the files found by the following steps. The same object must be returned each time. Furthermore, for a given FileList object and a given underlying file, the same File object must be used each time.

2) The FileAPI spec defines FileList as a sequence<File>

3) The Web IDL spec says this about sequences:

> The sequence<T> type is a parameterized type whose values are (possibly zero-length) sequences of values of type T. Sequences are always passed by value. In language bindings where a sequence is represented by an object of some kind, passing a sequence to a user agent implemented object will not result in a reference to the sequence being kept by that object. Similarly, any sequence returned from a user agent implemented object will be a copy and modifications made to it will not be visible to the object.

Doesn't WebIDL pass-by-value requirement conflict with the HTML5 
always-return-the-same-object requirement?


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