MV3: Service worker seems to stay open whenever any browser tab is open

[danjm]

Details in this slack thread: https://consensys.slack.com/archives/C02DUDT2WTU/p1675250040470039

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[danjm]

Hey team! Please add your planning poker estimate with Zenhub @brad-decker @DDDDDanica @pedronfigueiredo @PeterYinusa

[danjm]

https://developer.chrome.com/blog/longer-esw-lifetimes/

Not only should you refrain from keeping your extensions alive indefinitely (which we consider an anti-pattern), you should test your extensions to ensure that they're not doing this unintentionally.

We believe we have code to prevent the service worker staying alive indefinitely, but we should confirm that it is working. However, something about our contentscript might be unintentionally keeping the service worker alive, and this might be a new problem since the chrome changes described in the above linked blog post

[danjm]

I don't think this should be a beta blocker because the problem could be affected by future changes in the chrome extension api, and so we should wait until the further changes mentioned in the above linked blog post are more settled.

[gauthierpetetin]

Hi @jpuri @digiwand ,

• Do you have more context on this topic since the discussion started in February 2023?
• How is this behaviour (i.e. service workers staying alive) different from mv2 behaviour where background script is already staying alive?

[digiwand]

Hi @gauthierpetetin,

I don't have much additional context from Feb 2023

It might be helpful to note that the blog post @danjm shared was last updated 4 days after he commented above. In the doc

This post has been updated since we originally published it in January. We've added text indicating that calls to extension APIs reset the service worker's timeout clock, and clarified exactly when service worker timeouts will occur.

@danjm mentioned above:

We believe we have code to prevent the service worker staying alive indefinitely, but we should confirm that it is working.

Has it been confirmed this code is working or not working? It might be helpful to leave the tabs running for at least 5 minutes to rule out long-running tasks that could keep the service worker alive.

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How is this behaviour (i.e. service workers staying alive) different from mv2 behaviour where background script is already staying alive?

from my understanding, mv3 service workers are meant to terminate for better performance. I think this Q/A reference can help answer this

ref: https://developer.chrome.com/docs/extensions/migrating/known-issues/#manifest-v3-frequently-asked-questions

Q: Do we plan to support persistent Service Workers?
A: One of the key reasons for migrating from background scripts to service workers is the more memory efficient event-driven programming model which comes from the ephemeral nature of service workers. Consequently, we are not planning to support persistent service workers. However, to address the specific needs of extension developers, we are continuing to make many improvements to service workers. In particular: [...]

[gauthierpetetin]

Thanks a lot @digiwand !
@danjm , shall we prioritise this ticket next week, i.e. manually check if service worker stays alive indefinitely or not in our current MV3 implementation?