should document.open() inherit the controller?

What should happen if the current window is controlled by a service worker and script then calls document.open()? Should the service worker controller by inherited or not?

Per the html spec a new window should be created for document.open(). AFAIK, though, only firefox implements this and there is some discussion around aligning with the behavior where the window is preserved. @annevk has been looking at this recently.

Even with that in mind, though, should the controller be preserved or cleared?

I wrote a demo here:

https://sw-document-open.glitch.me/

The iframe shows its controller after the document.open(). You can also open the console to see if the "dynamic.js" script load inserted by the document.write() is intercepted.

Results are:

• Firefox: no controller, no dynamic.js fetch event
• Chrome: controller is inherited, dynamic.js fetch event is received
• Safari: controller is inherited, dynamic.js fetch event is received
• Edge: no controller, no dynamic.js fetch event

What is the desired behavior? My gut feeling is that it should probably be inherited similar to what we do for about:blank iframes, etc.

Start with the HTML spec behavior for document.open() and compare it with the service worker controller results in the linked demo. Check how the iframe controller and the dynamic.js fetch event behave in Firefox, Chrome, Safari, and Edge; done means the intended controller behavior is decided and documented.