Skip to main content

Coding standards

Coding style

Edlib is a collaborative effort. We want to keep the code consistent, rather than having each developer applying their own opinion on how code should look.

If your editor supports EditorConfig, some of the basic rules will be applied automatically.


New PHP code in Edlib should adhere to the PSR-12 coding style specification.

Backward compatibility

Composer packages

Breaking changes can come in the form of incompatible changes to a package's API, or change in behaviour. As examples:

  • Adding a method to an interface is an incompatible change to the API, as now every implementation of the interface almost certainly lacks this method.

  • A method named save() changed to do nothing would almost certainly be considered a breaking change. A judgement call has to be made in these cases.

Edlib's Composer packages follow the Semantic Versioning scheme. In short, the latest package in a major version series must remain backward compatible with the earliest. Upgrading from a package's 1.0.0 to 1.99.99 versions should not require any changes to the code consuming the package, for instance.

Adding stricter version requirements to a package's dependencies, including to PHP itself, is not a breaking change. Composer will not upgrade to dependencies where the requirements cannot be met, and will resolve the situation by keeping the current version of the package. As upgrading a major version is subject to manual review, and the tooling can handle version resolution, bumping the major version of a package to reflect increased dependency requirements is discouraged.

REST APIs/applications/microservices

Edlib's applications/microservices are unversioned and do not export any code, therefore any changes to interfaces or signatures do not matter, as long as every usage is updated.

In general, REST APIs must avoid introducing new requirements to JSON payloads. For instance, adding a new required entry to the JSON payload would be a breaking change, as this breaks existing endpoint uses.


Submitted code must pass the automated test suites.