User data is missing or lost when utilizing a snap instead of a traditional package

[Nicholas Skaggs]

I wanted to start a conversation around the user data story when using a snap to replace an application on my desktop that has been traditionally been delivered as a static binary or deb.

First, my expectation as a user is that when I replace my firefox from the archive with a firefox snap, that my user profile and preferences still exist. In other words, I expect nothing to change from my user perspective; it should be a seamless transition. Currently, this would require a manual step of moving my ~/.mozilla folder and profile over to the snap user data directory so it's available for the snap.

However even after migrating over to the new model of having my user data linked with the snap itself, another danger exists. Upon removing the snap, my user data is also gone. These two caveats are rather hidden and unexpected, and in the case of the latter, quite catastrophic for a user.

Let's discuss both short and long term solutions to this issue. In the short-term, a user's expectations around any application data is that data is retained. Upon removal, unless I used --purge, the application config is also retained. Applications themselves in the long term could better manage a user's data from the application config data itself. The application config by default is ethereal, while user data should be considered sacred and always retained unless explicitly removed by the user themselves. Since these lines are not always clear, data traditionally stored safely in a users HOME will now be subject to removal along with an application.

[John Lenton (chipaca)]

When you `snap remove` a snap, the snap-specific directories will be removed. Before that and unless --purge is specified a snapshot is created.