If I have two iOS apps, with bundle ids com.mycompany.A and com.mycompany.B, and they both have the shared group id of group.com.mycompany.B, then they can read/write data to same file (in shared defaults or, for example, a Realm database saved to the same shared group location).
What I have noticed is that if both apps get installed and some data X written to shared defaults (but data which isn't accessed by both apps i.e. if only app A uses this data), then if app A is deleted and reinstalled then X is not deleted in this situation (unless both apps A and B are deleted).
I guess that is to be expected as they both use the same group id and the OS won't clear that area out unless both apps are deleted.
However I think I am seeing a situation where if app A has group.com.mycompany.A as its group and app B has group.com.mycompany.B as its group, then this is still the same situation - data written by app B for doesn't get deleted if only app B is deleted/reinstalled on the phone. It won't get deleted unless both app B and A are deleted from the phone.
This is not what I was expecting.
I need to perform some more checks (its more complex to verify as app A is developed by one company and app B by another), but if this were to be the case would this be unexpected behavior by the OS? Presumably it would be unexpected as the container should be identified by the full group id and not a partial portion of the group id right?
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