1185920 - How to handle Android M Auto Backup

Status: RESOLVED WONTFIX

(Firefox for Android Graveyard :: General, defect)

Description

[Sebastian Kaspari (:sebastian; :pocmo)]

API overview:
https://developer.android.com/preview/backup/index.html

"Automatic backups are enabled for all apps installed on devices running the Android M Preview. No additional app code is required."

I'm now in a funky situation where I clear the app data of Nightly and about a minute later everything is back in place: Top Sites, History, my Sync account..

By default all app data is backed up. We can use the manifest to setup what data should be included in or excluded from the backup. Or disable auto backup.

There's a known issue around automatic backups and Google Cloud Messaging. We should evaluate if the browser could be affected by similiar issues:

"For apps that use Google Cloud Messaging for push notifications, there is a known issue where backing up the registration ID returned by Google Cloud Messaging registration can break push notifications for the restored app. It is important to query the API for a new registration ID after being installed on a new device, which is not be the case if the old registration ID was backed up. To avoid this, exclude the registration id from the set of backed up files."

Comment 1

[Sebastian Kaspari (:sebastian; :pocmo)]

At least two bugs seem to be related to auto backup somehow (or auto backup restores a broken state):

* Bug 1185444 - Can't install add-ons on Android M preview 2 (Nightly)
* Bug 1185923 - Android M: Nightly crashes when navigating to Air Mozilla

Maybe we should disable auto backup and then investigate.

Comment 2

[Sebastian Kaspari (:sebastian; :pocmo)]

Attachment: MozReview Request: Bug 1185920 - Disable app backups. r=mfinkle

Bug 1185920 - Disable app backups. r=mfinkle

Comment 3

[Sebastian Kaspari (:sebastian; :pocmo)]

The allowBackup has been available in previous Android versions too:
http://developer.android.com/guide/topics/manifest/application-element.html#allowbackup

It's worth noting that disabling this will also disable manual backups using adb, that some users might have been using previously.

Comment 4

[Mark Finkle (:mfinkle) (use needinfo?)]

Just historical reference, bug 1021742 was a different attempt to disable backups. In this case, we are talking about crashes and broken features, and not security issues.

Comment 5

[Sebastian Kaspari (:sebastian; :pocmo)]

Comment on attachment 8638541 [details]
MozReview Request: Bug 1185920 - Disable app backups. r=mfinkle

Google just released the following blog article yesterday:
http://android-developers.blogspot.de/2015/07/auto-backup-for-apps-made-simple.html

We might not need to hurry here and disable the backup, because:

> This feature will be available on Android devices running the upcoming M
> release. All you need to do to enable it for your app is update the 
> targetSdkVersion to 23.

And this explains why I've seeing auto backup running even though we do not target 23:

> You can test it now on the M Developer Preview, where 
> we’ve enabled Auto Backup for all apps regardless of targetSdkVersion.

So we can postpone our decision until we build against the M SDK and target API 23. Until then we can investigate and create a whitelist/blacklist for the backup.

Comment 6

[Sebastian Kaspari (:sebastian; :pocmo)]

See comment above. This will not affect us until we build with the Android M SDK and set targetSdkVersion to 23. I filed bug 1190375 for creating a whitelist/blacklist for backup.