In IPC mode sometimes the navigator.serviceWorker.ready promise would resolve with a slightly out-of-date registration. In particular, the registration.active property would be null. This should be impossible according to the spec.

Comment on attachment 8988605 [details] [diff] [review] Don't resolve ready promise until the registration has reached the right state version. r=mrbkap Similar to how registration state triggering an updatefound event raced with the update() promise, we also have an issue with registration state changes racing with the navigator.serviceWorker.ready promise. The ready promise is resolved in step 7.2 here: https://w3c.github.io/ServiceWorker/#activation-algorithm This happens after the registration and worker state have been updated. This can break in IPC mode when the container and registration need to connect to the parent upon creation. We want to replay the version change list to make sure events are fired correctly, but a site may also immediately access the ready promise. If the ready promise resolves immediately before the change list has been replayed, then the script may see a resolved ready promise reaction before the registration.active property is set. This patch fixes the problem by making the .ready code delay resolving the promise until the binding object has reached the correct state version.

Comment on attachment 8988605 [details] [diff] [review] Don't resolve ready promise until the registration has reached the right state version. r=mrbkap Review of attachment 8988605 [details] [diff] [review]: ----------------------------------------------------------------- This is really cool. It's exactly the patch I expected to see.

Try build in comment 1.

Patch failed to apply: mozilla@ubuntu:~/mozilla-unified$ hg qpush applying bug1472005_ready.patch patching file dom/serviceworkers/ServiceWorkerRegistration.cpp Hunk #1 FAILED at 152 Hunk #2 FAILED at 336 2 out of 2 hunks FAILED -- saving rejects to file dom/serviceworkers/ServiceWorkerRegistration.cpp.rej patching file dom/serviceworkers/ServiceWorkerRegistration.h Hunk #1 succeeded at 115 with fuzz 1 (offset 0 lines). Hunk #2 FAILED at 145 1 out of 2 hunks FAILED -- saving rejects to file dom/serviceworkers/ServiceWorkerRegistration.h.rej patch failed, unable to continue (try -v) patch failed, rejects left in working directory errors during apply, please fix and qrefresh bug1472005_ready.patch

Rebased

Pushed by ben@wanderview.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/4eb950e44164 Don't resolve ready promise until the registration has reached the right state version. r=mrbkap