In a recent post to his site Mathias Noback looks at the use of semantic versioning, introducing some of its basic concepts and how it can relate to the work done in Symfony bundles.

Semantic versioning is an agreement between the user of a package and its maintainer. The maintainer should be able to fix bugs, add new features or completely change the API of the software they provide. At the same time, the user of the package should not be forced to make changes to their own project whenever a package maintainer decides to release a new version.

He breaks down what the version numbering represents (major, minor and patch versions) and how they work with Symfony's "semver" to handle issues that come with backwards compatibility concerns. He then looks at a few things to consider when versioning your bundles and how it relates to the underlying libraries it might use:

• Bundles expose an API themselves
• The API of a bundle leads a life on its own
• A library may contain bugs that are totally unrelated to the bundle
• A library may contain features that are not implemented by the bundle

Ultimately, he suggests that bundle versioning should have nothing to do with the underlying libraries/packages. It's his opinion that they should only be reversioned when there is a change in the actual bundle.