Losing data between updates (chrome packaged app)

Question

I'm working on a chrome packaged app that saves a lot of data locally. I recently put it on the chrome store. To my dismay, whenever my user's chrome installation updated the app (v1.1.1 to v1.1.2 for example), all their local data was gone (indexeddb data). Why is this so?

Is it the expected behavior to wipe out all the databases on an update? Is there any way to prevent this other than not pushing out updates?

(Also where can I report this issue/bug, if it is one?)

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Update: filed a bug report, but now I can't reproduce the issue. Not sure if it was fixed or my situation was a fluke.

Answer 1

I put in an issue:

http://code.google.com/p/chromium/issues/detail?id=169417

one of the developers got back to me and said:

I can't remember the release numbers off the top of my head, but at some point when we turned on correct partitioned storage, there would have been one-time data loss. This was done before packaged apps rolled out officially to stable. If the loss of data happened across an chrome upgrade, then I would say it's expected. It certainly shouldn't be happening anymore.

Answer 2

The documentation is fuzzy on this:

https://developer.chrome.com/trunk/apps/app_lifecycle.html

Preventing data loss

Users can uninstall your app at any time. When uninstalled, no executing code or private data is left behind. This can lead to data loss since the users may be uninstalling an app that has locally edited, unsynchronized data. You should stash data to prevent data loss.

I hope they will elaborate on this, because zapping user data on every upgrade is not a great user experience.