DependencyThat

DependencyThat is a conceptual framework for expressing and analyzing dependencies between software components, tasks, and resources. In this model, dependencies are not merely about the presence of one component, but about the properties that the dependent component requires of its dependency. The term is used in theoretical discussions and in some constraint-based tooling as a way to formalize critical quality attributes, compatibility, and policy constraints within a dependency graph.

Formalism: A dependency is represented as a triple (A, B, C) where A depends that B satisfies condition C. The condition C can specify version ranges, feature flags, licensing terms, performance characteristics, or interface contracts. The dependencies form a directed graph, and satisfiability is determined by constraint solving or propagation techniques to detect unsatisfiable or conflicting requirements.

Applications: DependencyThat informs automated resolution in build systems and package managers, release planning, and IT service management by capturing more nuanced constraints than presence alone. It supports impact analysis by tracing how changes to B affect A through the predicate C and can help in planning upgrades to preserve compatibility.

Relation to other concepts: It shares goals with constraint-based dependency management and policy-based access control. It differs by focusing on the semantic content of the required property rather than only the dependency edge. Some tooling sketches exist as theoretical models or prototypes; practical adoption depends on standardizing predicates and scalable solver techniques.

Limitations and outlook: As a formal model, DependencyThat can be complex to apply at scale, and real-world adoption requires consistent predicate semantics and interoperable representations. Nevertheless, it provides a structured language for discussing dependency constraints beyond simple version matching.