record that Gamepad.buttons creates GamepadButtons

record that Gamepad.buttons creates GamepadButtons

This also extends the html generator to be able to generate List implementations with nullable element types

Fixes https://github.com/dart-lang/sdk/issues/27073

R=sra@google.com, terry@google.com

Committed: https://github.com/dart-lang/sdk/commit/1d749a2fec4f49e07a471769acee92926cf17353

[Harry Terkelsen, 2016-08-15 17:11:25]

het@google.com changed reviewers:
+ sra@google.com, terry@google.com

[Harry Terkelsen, 2016-08-15 17:36:46]

Hmm, actually now I'm running into a different problem. dart2js is assuming that
in:

window.getGamepads().forEach((gamepad) {
  ...
});

that gamepad cannot be null, but in my sample program, gamepad is null (I don't
have a gamepad). How can I tell dart2js that Gamepad.buttons returns
List<GamepadButton|Null>?

[sra1, 2016-08-15 17:58:46]

On 2016/08/15 17:36:46, Harry Terkelsen wrote:
> Hmm, actually now I'm running into a different problem. dart2js is assuming
that
> in:
> 
> window.getGamepads().forEach((gamepad) {
>   ...
> });
> 
> that gamepad cannot be null, but in my sample program, gamepad is null (I
don't
> have a gamepad). How can I tell dart2js that Gamepad.buttons returns
> List<GamepadButton|Null>?

Only the top level type is specified by @Returns.
The elements should be effectively dynamic.
Is non-null what dump-info inferred?

[Harry Terkelsen, 2016-08-15 18:09:51]

On 2016/08/15 17:58:46, sra1 wrote:
> On 2016/08/15 17:36:46, Harry Terkelsen wrote:
> > Hmm, actually now I'm running into a different problem. dart2js is assuming
> that
> > in:
> > 
> > window.getGamepads().forEach((gamepad) {
> >   ...
> > });
> > 
> > that gamepad cannot be null, but in my sample program, gamepad is null (I
> don't
> > have a gamepad). How can I tell dart2js that Gamepad.buttons returns
> > List<GamepadButton|Null>?
> 
> Only the top level type is specified by @Returns.
> The elements should be effectively dynamic.
> Is non-null what dump-info inferred?

Yes, for the forEach closure it infers that gamepad is: Union of
[[exact=Gamepad], [subclass=JSNumber]]

I think it's because we have window.getGamepads() return a _GamepadList which I
think isn't annotated to return null on indexing operations. The Gamepad API is
weird... the first element is always null:
https://w3c.github.io/gamepad/#navigator-interface-extension

[Harry Terkelsen, 2016-08-15 23:53:39]

Description was changed from

==========
record that Gamepad.buttons creates GamepadButtons

Fixes https://github.com/dart-lang/sdk/issues/27073
==========

to

==========
record that Gamepad.buttons creates GamepadButtons

This also extends the html generator to be able to generate List implementations
with nullable element types

Fixes https://github.com/dart-lang/sdk/issues/27073
==========

[Harry Terkelsen, 2016-08-15 23:54:02]

PTAL. I have added nullable element type functionality to the generator

[sra1, 2016-08-16 16:51:59]

LGTM for the dart2js side.
I'm not sure how this affects Dartium - Terry?

[Harry Terkelsen, 2016-08-16 20:35:54]

Added a test, PTAL Terry

[terry, 2016-08-16 20:50:30]

lgtm

[Harry Terkelsen, 2016-08-16 20:56:37]

Description was changed from

==========
record that Gamepad.buttons creates GamepadButtons

This also extends the html generator to be able to generate List implementations
with nullable element types

Fixes https://github.com/dart-lang/sdk/issues/27073
==========

to

==========
record that Gamepad.buttons creates GamepadButtons

This also extends the html generator to be able to generate List implementations
with nullable element types

Fixes https://github.com/dart-lang/sdk/issues/27073

R=sra@google.com, terry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/1d749a2fec4f49e07a471769acee92926cf17353
==========

[Harry Terkelsen, 2016-08-16 20:56:38]

Committed patchset #4 (id:60001) manually as
1d749a2fec4f49e07a471769acee92926cf17353 (presubmit successful).