libc

aded side by side, there are scenarios where things break. For example, the "libc apocalypse" situation in Rust https://github.com/rust-lang/libc/issues/547 Here after the "libc" module released a major version, the definition for the `void` C type in two versions of the lib are considered by the compiler as two different types, resulting in breakages everywhere around the library ecosystem. There are also scenarios for dynamic languages / runtime errors. > None of this is the responsibility of semver. In fact, semver would help the language provide tooling to detect that kind of "hey this instance is from foo-1.0 but you're trying to consume it in foo-2.0". And what's next after it detected the dependency hell? It's too late and the person suffering is not in the position to fix it. You have to upgrade to "authentication 1.1.2" for security compliance, because the version 1.1.1 has known vulnerabilities. But that breaks the application, because the maintainer of the lower level dependency "commons-logging" happily breaks compatibility, proud of himself following the engineering best practice SemVer and increasing the major version number. What would you do? Leave the vulnerable lib in the app? Patch the libraries? The promise was to prevent dependency hell, not to detect it. Quoting the ticket and reiterating the point of my first comment above: > Once again, the point of this ticket is to: > 1. Remove the false promise that SemVer solves dependency hell by simply increasing major version. > 2. Discourage unnecessary compatibility breakages, when it's trivial to maintain compatibility. > 3. Several sentences of advice for the cases when comparability breakage is really needed.

ultiple library versions in one app. SemVer is a product of Ruby community, and Ruby has a global namespace for classes and unable to have several versions of a lib simultaneously. In 2000s Ruby library authors were breaking compatibility left and right, neglecting elementary compatibility practices. If you were working on an application, practically every time when you update dependencies, the application would break. So (in 2011 ?) they came out with this "manifesto" (Why such a big name? This scheme of versioning was well established in linkers and sonames of all Unix-like systems for decades - it goes back to at least 1987 paper "Shared Libraries in SunOS"). It's a good thing SemVer acknowledged finally that compatibility is a serious matter. Only that it's better to discourage compatibility breakages. An in cases when it's really needed (I agree such cases exists), there are things to take care of in addition to simply increasing major version num.