When a system update is applied, the system apps that were previously installed but aren't installed now should be deleted. However, the code first deletes the appp from the webapps table and then tries to use a property from it.

NOTE: Please see https://wiki.mozilla.org/Release_Management/B2G_Landing to better understand the B2G approval process and landings. [Approval Request Comment] Bug caused by (feature/regressing bug #): User impact if declined: If a system update deletes a previously installed system app, it'll fail (and stop processing the updated app). In the best case the deleted app will still be available, on the worst case there will be some apps not working correctly. Testing completed: Risk to taking this patch (and alternatives if risky): Low, it just changes the place where the app is deleted from the registry. String or UUID changes made by this patch:

Antonio - Can you add a mochitest for this?

To be honest, I don't have the most remote idea about how to test this with mochitest. This is something that only runs at the first run after each system update and only if MOZ_SYSTEM_GONK is defined. I don't know if (or how) can I simulate that on mochitest. Any ideas, Fabrice?

Comment on attachment 753713 [details] [diff] [review] Deletes the app data from the registry after deleting all the private data, insted of before Review of attachment 753713 [details] [diff] [review]: ----------------------------------------------------------------- good catch, thanks! I'd love to have test too, but I don't think we can test OTA updates within mochitests. That's worth a followup though.

This actually explains a lot of bugs we've had when we did such things as: - Switch marketplace from a hosted to a packaged app - Switch the maps app from hosted to packaged We aren't deleting the old app, so we the two icons issue probably because we never deleted the old app.

I'm guessing the easiest way I could test this would be something like the following: 1. Generate a custom build with some extra apps that's older 2. Apply an OTA update 3. Verify the extra apps are deleted on update Does that sound right?

Yeah, that sounds right. As the only caveat, the extra apps should be marked as non removable (otherwise they're not considered system apps and thus they're not removed on a system update).

https://hg.mozilla.org/releases/mozilla-b2g18/rev/ab8f017c5171 https://hg.mozilla.org/releases/mozilla-b2g18_v1_0_1/rev/9ff01472b61b