ServiceWorker client creation URL + No-Vary-Search

[hiroshige-g]

Minor (Pri-4) follow-up of #387:

For the simple case of #388 (comment)

• Prefetch /page?param=1

  • Server responds with No-Vary-Search: "param"

• Navigate to /page?param=2

Desired result:

• Service worker for /page?param=1 observes the prefetch
• Prefetch bytes from /page?param=1 response are served
• Created Document's URL is /page?param=2
• Controlling service worker is /page?param=1 SW

For prefetch, ServiceWorker client creation URL is /page?param=2 because https://wicg.github.io/nav-speculation/prefetch.html#create-navigation-params-from-a-prefetch-record creates the ServiceWorker client based on the navigation URL.

For prerender, IIUC ServiceWorker client creation URL is /page?param=1, because https://wicg.github.io/nav-speculation/prerendering.html#prerendering-traversable-update-the-successor-for-activation Step 2 updates Document URL but doesn't update ServiceWorker client creation URL.

I don't expect this affect real use cases and thus Pri-4, no need to fix at least for mid term?
Anyway filing this issue to track (I'm sure I'll forget).

[domenic]

Hmm, #387 was intended to fix this. The commit message says

For determining the active service worker, we carry over the one that controlled the last response of the prefetch.

https://wicg.github.io/nav-speculation/prefetch.html#note-no-vary-search-final-service-worker-impact also is trying to be clear about what we're doing.

I think the spec text here is correct, so could you explain why you're saying

creates the ServiceWorker client based on the navigation URL.

?

[domenic]

@hiroshige-g, can you let me know if I'm missing something here?

[hiroshige-g]

The remaining thing this issue is tracking is ServiceWorker client creation URL for prerendering.
I (weakly) feel it should be /page?param=2 to align with prerendered Document URL (which is already /page?param=2) and with prefetch case.

For the rest, Yes, everything should be fixed, namely active service worker, Document URL and ServiceWorker client creation URL for prefetch should be fixed by #387.

[domenic]

Excellent, thank you!

I (weakly) feel it should be /page?param=2 to align with prerendered Document URL (which is already /page?param=2) and with prefetch case.

I agree with this. We should fix it.

For the rest, Yes, everything should be fixed, namely active service worker, Document URL and ServiceWorker client creation URL for prefetch should be fixed by #387.

Great. I will remove this from the "Upstream prefetch" milestone.