API Changes and StabilityΒΆ

CCL follows the conventions of semantic versioning. Semantic versioning is a consistent set of rules for constructing CCL version numbers so that CCL users can understand when new releases have backwards compatible APIs.

An API breakage is anything that modifies the name or call signature of an existing public-facing function or variable in the Python code in such a way that the change is not backwards compatible. For example, removing a Python keyword argument is an API breakage. However, adding one is not. Significant changes to the behavior of a function also count as an API breakage (e.g. if an assumption is changed that causes different results to be produced by default). Fixing a bug that affects the output of a function does not count as an API breakage, unless the fix modifies function names and arguments too as described above.

If the API is broken, the CCL major version number must be incremented (e.g. from v1.5.0 to v2.0.0), and a new tagged release should be made shortly after the changes are pushed to master. The new release must include notes in CHANGELOG.md that describe how the API has been changed. The aim is to make it clear to users how their CCL-based code might be affected if they update to the latest version, especially if the update is likely to break something. All API changes should be discussed with the CCL team before being pushed to the master branch.