Daniel Moch shared his thoughts on semantic versioning and how he treats external libraries that violate its inherent contract with developers.

So as not to bury the lede, I’ll get to my point: Semantic Versioning is a meta-API, and maintainers who are cavalier about violating it can’t be trusted to created stable contracts. I’ve lost patience for breaking changes making their way to my code bases without the maintainers incrementing the major version of their projects, especially in language ecosystems where Semantic Versioning is expected, and in such cases I’m going to begin exploring alternative options so I can ban such libraries from my projects—personal and professional—altogether.
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If you work in a language ecosystem where Semantic Versioning is the de facto norm, where violating it can wreak havoc downstream, then please play nice and follow its dictates. Instead of viewing it as a straight jacket, try to see it as an algorithm to determine what your next release number should be. We should all like algorithms!