MV3 reinjects on service worker restart

[twschiller]

• In this branch: #7228: chrome.sidePanel POC pixiebrix/pixiebrix-extension#7232, was seeing console logging indicating webext-inject-on-install is running multiple times
• Does it need to check for https://developer.chrome.com/docs/extensions/reference/api/runtime#event-onStartup or similar?

[fregante]

onStartup refers to the browser startup, not the extension.

onInstalled covers the common scenario, but it won't work if they user re-enables a disabled extension, or if you reload it during development.

I recently created an event for this, based on chrome.session, I'll try using it here: https://github.com/fregante/webext-events/blob/main/source/on-extension-start.md

It seems that soon they'll work on the onEnabled event, which is the right API for us:

• runtime.onEnabled might be available this year, replacing onExtensionStart webext-events#16

[twschiller]

At least in our project, it's not a high priority as we guard against re-injection. I just wanted to capture the issue as something to be aware of (and could impact other users of this library)