Service workers cannot be disabled in Canary

[superpoincare]

Prerequisites

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• I tried to reproduce the issue when...
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• I checked the documentation to understand that the issue I report is not a normal behavior

Description

On Chrome Canary, service workers can't be blocked by the filter $csp=worker-src 'none'

A specific URL where the issue occurs

https://www.youtube.com/

Steps to Reproduce

1. On a fresh install of Chrome Canary with uBO installed, add this filter $csp=worker-src 'none'
2. In advanced settings, change suspendTabsUntilReady to yes (as described here)
3. Visit YouTube.

Expected behavior:

Service worker is not loaded. In Chrome stable this is working fine.

Actual behavior:

Service worker gets loaded as can be seen in developer tools.

Your environment

• uBlock Origin version: v1.34.0
• Browser Name and version: Version 92.0.4483.0 (Official Build) canary (64-bit)
• Operating System and version: Windows 10 Home Single Language, 20H2, OS build: 19042.928

[uBlock-user]

Did you un-register all service-workers from chrome://serviceworker-internals page in Chrome ?

[superpoincare]

Oh yeah did that. And various other ways like clearing all caches, site specific data etc. too.

This was problematic even before 90. suspendTabsUntilReady is very basic on Chrome.

[gorhill]

In advanced settings, change suspendTabsUntilReady to yes (as described here)

So this happens at browser launch?

Documentation for suspendTabsUntilReady:

Disclaimer: especially in Chromium based browsers, even with this setting enabled, it's impossible for uBO to guarantee with 100% certainty that everything will be properly blocked when the browser is launched. This is a by-design browser issue -- do not open an issue on uBO issue tracker about this.

[superpoincare]

@gorhill

I didn't check that. I used it with caches fully cleared and loading sites. I just mentioned "suspendTabsUntilReady" for the sake of completeness. So likely the issue is not that.

On Chrome stable (90), I don't face this issue either with browser launch or anytime. The service worker is always blocked.

But in Canary even with all site data cleared (ie service workers cleared too), the service worker appears at the end of the page load.

I think it's probably because for some reason Canary prevents uBO from adding the worker-src csp header.

[gorhill]

So likely the issue is not that

Easy to verify, open a new Chrome instance with no tab opened, ensure there are no workers in effect using chrome://serviceworker-internals/, open uBO's logger, then open Youtube and see what the logger says and what the dev console says.

Also, in general Canary is unsupported, too many instances of malfunctions attributed to uBO while the browser is the issue, so if you can't reproduce the issue with stable or beta Chrome, then its most likely a browser issue.

[superpoincare]

Yeah, when I open a browser without clearing caches and see chrome://serviceworker-internals/ I see the youtube service worker registered. Both when I unregister and don't do anything, it appears again on visiting the site.

But it seems to me that since the service worker anyway installed on a fresh load, it will load again.

On Chrome stable I see this message in Devtools console:

Refused to create a worker from 'https://www.youtube.com/sw.js' because it violates the following Content Security Policy directive: "worker-src 'none'".

which is absent in Canary.

But I understand your point about Canary having its own issues which may not appear when it becomes stable. So I think you can close the issue and maybe if we see it in Beta just before Chrome release, I can open again?

[uBlock-user]

But I understand your point about Canary having its own issues which may not appear when it becomes stable. So I think you can close the issue and maybe if we see it in Beta just before Chrome release, I can open again?

That would make it a Chromium issue, you would need to file a report on their bug tracker.