Handle subscriptions with deleted products

[aldesantis]

When a product is soft-deleted, it should also be removed from all active subscriptions, or perhaps we shouldn't allow deleting a product that has active subscriptions associated.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It might be closed if no further activity occurs. Thank you for your contributions.

[luca-landa]

Since we can't assume the subscribable class will always be a subclass of Spree::Variant, it may be harder to fix subscriptions on subscribable deletion.
Moreover, it may be difficult and/or risky trying to prevent its deletion, so I think we should allow their deletion.

If we want to allow it, I see two main ways:

• handle the case while processing the subscription, checking for subscribables existence and removing them before processing, if needed
• handle the case in a (IMHO) cleaner way through decoration of the subscribable class.
  • in that case we could apply the decoration only if the class is a Spree::Variant, or maybe the restriction could be that it needs to be an ActiveRecord model and then hook up the fix on its after_deletion or after_discard callbacks.

Any opinions or suggestions on possibilities I'm missing?

[aldesantis]

@luca-landa thanks for the analysis here! I think removing the variant from any associated subscriptions is the right way to go here. I also think we should only do this when we're dealing with Spree::Variant, and just delegate the logic to the user in case they're using a custom subscribable class (which is unlikely, anyway).

[luca-landa]

does it make sense to delete the Spree::Variant from every subscription? Or should it be removed from active subscriptions only? (what about soft-deleting it from every subscription?)