That also is a really awful change and probably broke someone in production. Really there is no reason for the not function to take more than one argument. But if you have decided to overload the meaning to NAND, you'd better not later change it to NOR!
That is asinine. Why not change it in 5.x->6.0 if they knew it was a problem. Why even use version numbers at that point? Just use DateVer or 0ver at that point.
> Why not change it in 5.x->6.0 if they knew it was a problem
Because Rails explicitly has a versioning policy where minor versions are equivalent to SemVer major versions (but with deprecation notice in a previous minor version) and where major versions are also SemVer major with subjective significance distinctions; they call it “shifted SemVer”.
Sure, but like, you don't have to break code on .Y changes.
Changing semantics of a query operator is something worth saving for a "big major" update, if you change it all.
Some breaking changes are really obvious and easy to catch. Others can introduce pernicious bugs which slip through tests. The change Mongoid is solidly the latter. And yeah, they say they use actual Semver.
These sorts of changes do in fact happen fairly frequently and developers need to be aware that they can't blindly accept upstream dependency changes.