1598047 - r.registrationFront error causes Debugger's sources to fail loading

Status: RESOLVED FIXED

(DevTools :: Debugger, defect, P2)

Description

[:Harald Kirschner :digitarald]

Attachment: image.png

Happens twice when opening Debugger on https://firefox-dev.tools/debugger-examples/examples/todomvc/ . Couldn't reproduce after restart.

Debugger sources didn't load.
Console links to Debugger didn't work.

Comment 1

[Julian Descottes [:jdescottes]]

I think what happens is that we process two workers of type "service", where one doesn't have a matching registration. This means we create a "fake" service worker at :

            worker.fetch = front.fetch;

            // If a service worker registration could not be found, this means we are in
            // e10s, and registrations are not forwarded to other processes until they
            // reach the activated state. Augment the worker as a registration worker to
            // display it in aboutdebugging.
            worker.scope = front.scope;
            worker.active = false;
            result.service.push(worker);

this worker has no registrationFront, so the next time we get a worker of type service and loop on all existing "service workers", we will crash.

The code that throws is

            const { isParentInterceptEnabled } = r.registrationFront.traits;
            if (!r.newestWorkerId || !isParentInterceptEnabled) {
              return r.scope === front.scope;
            }

I think we should have made isParentInterceptEnabled a root actor trait instead of a service-worker-registration trait, but here since r.newestWorkerId should also be false in this situation, checking isParentInterceptEnabled is not needed.

Changing this code to:

            // r.registrationFront might be undefined if the service worker was just created from a worker without
            // any associated registration
            const isParentInterceptEnabled = r.registrationFront ? r.registrationFront.traits.isParentInterceptEnabled : false;
            if (!r.newestWorkerId || !isParentInterceptEnabled) {
              return r.scope === front.scope;
            }

should be enough. Might be hard to write a test for it though.

Comment 2

[Julian Descottes [:jdescottes]]

Attachment: Bug 1598047 - Fix js error when calling listAllWorkers with service workers missing their registration

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/82f59a83b7df
Fix js error when calling listAllWorkers with service workers missing their registration r=ladybenko

Comment 4

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/82f59a83b7df