What makes this tricky is that golang-github-golang-protobuf-1-3 provides pre-APIv2 protobuf libraries and golang-github-golang- protobuf-1-5 provides APIv2. While some code might compile with both versions, they are runtime incompatible and mixing resulting binaries will result most likely in crashes.
I think that a Breaks+Replaces as suggested in bug #1109655 isn't correct. I'm not familiar enough with the details to be able to confidently suggest the correct solution to this problem. I did mention this on the debian-go mailing list hoping to solicit feedback from others. The affected packages in bugs #1109513-7 are all golang development libraries, which aren't expected to be used other than building golang packages. I think the odds of an end user encountering the upgrade issue is low, although it would still be good to fix. Mathias
signature.asc
Description: This is a digitally signed message part