Add test for Joint session state manipulation

[jutaz]

Some browsers don't seem to agree on how top-level container should handle the navigation of the child, particularly around if the state should be overwritten by the child or not. This is particularly prominent in WebKit based browsers, such as Safari.

As far as I've tested this, it appears that these browsers pass the test:

• Chrome 73.0.3683.103
• Chrome Canary 75.0.3767.0
• Firefox ESR 60

These browsers don't pass the test:

• Safari 12.1 (14607.1.40.1.4)
• Safari TP (Safari 12.2, WebKit 14608.1.14)

This leads me to believe that Chrome & Firefox's implementation is correct, thus this test is geared to pass in these browsers. Ideally we'd follow the history spec, but as far as I'm aware, it does not specify how browsers should work in this particular scenario.

Looking at this pragmatically as well, it appears that keeping the window.history.state in the navigation makes sense, as the top window did not actually change it's state, just the child iframe, even if navigation occurred and going back in history means that child iframe will navigate back. That, however, does not alter the state of the parent window, which is why it appears that implementation in Chrome/Firefox seems correct.

References

• There is a bug report opened in Webkit repo for this issue https://bugs.webkit.org/show_bug.cgi?id=196990

[annevk]

If push state history is indeed per global this looks correct to me. It would be nice to assert the child's state before you navigate it as well.

@cdumez you probably wanna look at this and comment regarding WebKit's perspective.

[annevk]

(Forgot to say I really appreciate your work on this @jutaz!)

[jutaz]

It would be nice to assert the child's state before you navigate it as well.

Can do 👍

[annevk]

I'll leave this open for a bit to let @cdumez comment, but do ping again if you feel like you've been waiting too long and I'll get it merged. Thanks again!

[jutaz]

Thanks @annevk! I'd love to hear from Webkit's team, so all good for now 👍

[jutaz]

Bumping this - would love to get this merged 🙏

[jutaz]

Thanks @annevk!