1638505 - Subresource integrity checks intermittently failing when using a service worker and dev tools are open.

Status: UNCONFIRMED

(Core :: DOM: Service Workers, defect, P3)

Description

[murray]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:76.0) Gecko/20100101 Firefox/76.0

Steps to reproduce:

I'm running a service worker for PWA functionality.
This issue only occurs in Firefox. (I'm running on Ubuntu 20.04)
Intermittently when reloading the page with dev tools open, the integrity and cors checks fail for included resources like Bootstrap/JQuery from CDNs resulting in an unstyled page without JS functionality.

Actual results:

Integrity and CORS checks intermittently fail when using a service worker and the dev tools are open.
It has never happened without the dev tools being open. It only happens when a service worker is involved.
Sometimes a hard refresh (Ctrl - F5) fixes the issue without closing the dev tools but sometimes not.

Expected results:

The integrity and cors checks should not fail while the dev tools are open.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 2

[Honza Bambas (:mayhemer)]

murray, can you provide a life test case or at least reveal if the site uses <link rel=preload> (either in the markup or dynamically)? If this has started recently and is relatively easy to reproduce, could you try mozilla regression to bisect to the changeset that introduced this possible regression?

Thanks.