I've built an R package that uses a mix of libraries licensed under GPL-2 and GPL-3. From what I've read, because of this dependency, my package will also have to be GPL.
If a library is released under the GPL (not the LGPL), does that mean that any software which uses it has to be under the GPL or a GPL-compatible license? Yes, because the software as it is actually run includes the library.
Confusingly, one can find R packages under MIT, even though they depend on a package under GPL. For example, memoise is MIT even though it depends on digest (which is GPL-2).
Am I right about my having to use GPL and does it matter if I choose GPL2/3?