[globnomulous]

This is really surprising.

One of the first things I learned when I started shipping APIs and software packages is that the behavior you expose and the interface you provide for it have to be written in stone. The alternative is to break code and other packages that depend on it. Your package's changes are always somebody else's bugs. Compile-time errors and static analysis provide helpful guarantees and reduce suffering, but that doesn't change the fact that when you introduce changes you're still throwing Legos on the floor of someone's bedroom while they sleep.

Major-version revisions by definition allow for breaking changes, but a breaking change needs strong justification: either you know nobody or few users are using what you've changed, or there's broad consensus that there's a bug (but one that didn't need to be fixed with a minor-version update, so it's probably a design problem, not a code bug), or the people using it broadly agree on the need for or benefit of the change.