Implement "global" property of global object

Implement "global" property of global object

BUG=v8:5537
R=littledan@chromium.org

[targos, 2016-12-23 17:31:21]

https://codereview.chromium.org/2599903003/diff/20001/test/mjsunit/global.js
File test/mjsunit/global.js (right):

https://codereview.chromium.org/2599903003/diff/20001/test/mjsunit/global.js#...
test/mjsunit/global.js:12: assertEquals(globalObject, thisObject);
This test fails and I don't understand why.

[Dan Ehrenberg, 2016-12-23 17:44:41]

Description was changed from

==========
Implement "global" property of global object

BUG=5537
R=littledan@chromium.org
==========

to

==========
Implement "global" property of global object

BUG=v8:5537
R=littledan@chromium.org
==========

[ljharb, 2016-12-23 18:04:22]

ljharb@gmail.com changed reviewers:
+ ljharb@gmail.com

[ljharb, 2016-12-23 18:04:23]

https://codereview.chromium.org/2599903003/diff/20001/test/mjsunit/global.js
File test/mjsunit/global.js (right):

https://codereview.chromium.org/2599903003/diff/20001/test/mjsunit/global.js#...
test/mjsunit/global.js:12: assertEquals(globalObject, thisObject);
On 2016/12/23 17:31:21, targos wrote:
> This test fails and I don't understand why.

Are the tests run in strict or sloppy mode?

You may want to just use `Function('return this')()` to avoid indirection.

[targos, 2016-12-23 21:58:23]

Found the problem. I had to use the global proxy

[Dan Ehrenberg, 2016-12-23 23:34:05]

On 2016/12/23 21:58:23, targos wrote:
> Found the problem. I had to use the global proxy

Thanks for jumping in and implementing this!

Hmm, do you know why this has to be done differently from all the other things
which are installed on the global object?

Could you turn this on only behind a flag? We typically develop new features
under the flag HARMONY_INPROGRESS, and promote them to staging and shipping in
separate patches. See https://github.com/v8/v8/wiki/Feature%20Launch%20Process
for more details.

[targos, 2016-12-24 14:33:08]

On 2016/12/23 at 23:34:05, littledan wrote:
> On 2016/12/23 21:58:23, targos wrote:
> > Found the problem. I had to use the global proxy
> 
> Thanks for jumping in and implementing this!
> 
> Hmm, do you know why this has to be done differently from all the other things
which are installed on the global object?
> 
> Could you turn this on only behind a flag? We typically develop new features
under the flag HARMONY_INPROGRESS, and promote them to staging and shipping in
separate patches. See https://github.com/v8/v8/wiki/Feature%20Launch%20Process
for more details.

I put it behind a --harmony-global flag.

I may be wrong about the global proxy thing, but if I reference the global
object on itself, the equality `this === global` is lost...

[targos, 2017-01-05 10:33:02]

What would be the next step?

[Dan Ehrenberg, 2017-01-05 15:17:40]

On 2017/01/05 10:33:02, targos wrote:
> What would be the next step?

Unfortunately, the next step would be waiting for the committee to resolve the
web-compatibility issues, e.g., with a different name. The current proposal
seems pretty plainly to break the web. See
https://github.com/tc39/proposal-global/issues/20 for more information.