Annoy the user when pinning packages from incompatible repositories
Many users are following poorly-written tutorials and installing packages from incompatible repositories. For some non-Alpine distros, this may be allowed, but for Alpine it is not permitted to mix packages from different releases. There should be some mechanism for apk to tell the user that this is not supported. Two simple heuristics for Alpine would be checking the repository URL and the repository version, and if these don't match then raise an error. However, this may not work for third-party repositories or non-Alpine distros.