What type of architectural violation would be flagged if a Foundation module has a strong dependency on an End-User module?

A strong dependency of a Foundation module on an End-User module indicates an upward dependency, which is generally regarded as a violation in OutSystems architecture. Foundation modules are intended to provide core services and functionalities that should remain independent of higher-level presentation or user interface concerns that are typically encapsulated within End-User modules.

When a Foundation module strongly depends on an End-User module, it breaks the architectural principle that the core functionalities should not depend on the presentation layer. This can lead to situations where changes in the End-User module can adversely affect the Foundation module, potentially introducing bugs or complications into the more stable foundational code. Such a violation indicates a design flaw and suggests that the architecture is not properly layered, which can complicate maintenance and scalability.

In a well-structured OutSystems application, Foundation modules should be agnostic of the user interface and should serve as a stable base for other modules, facilitating reusability and clarity in the application architecture. This design principle reinforces best practices in software engineering regarding separation of concerns and maintainability.