> I better make sure that all future versions of it also always return an even number of characters, just in case some moron decided to bank their application's functionality on that?
Oh yes, this does happen. There's even a name for that: ossification (https://en.wikipedia.org/wiki/Protocol_ossification). You can't change your API/protocol, because "some moron" started depending on implementation details.
It's easy to say "your application deserves to break" from an ivory tower, but it's often not easy or viable to fix it (for instance, it might have different owners, it might no longer be maintained, it might be more expensive to change, etc). And the change which broke that application was not in it; the blame naturally goes to what was changed last.
Oh yes, this does happen. There's even a name for that: ossification (https://en.wikipedia.org/wiki/Protocol_ossification). You can't change your API/protocol, because "some moron" started depending on implementation details.
It's easy to say "your application deserves to break" from an ivory tower, but it's often not easy or viable to fix it (for instance, it might have different owners, it might no longer be maintained, it might be more expensive to change, etc). And the change which broke that application was not in it; the blame naturally goes to what was changed last.