Formalizing a Hoare Calculus for Choreographic Programming

Choreographic programming is a paradigm where developers write the global specification (called choreography) of a communicating system, and then a correct-by-construction distributed implementation is compiled automatically. Choreographies formalize the way many practitioners think about distributed protocols, and are a natural framework in which to prove properties of such protocols. Previous work has introduced a Hoare calculus for reasoning about choreographies. In this article, we show how a formalization of that work in a theorem prover revealed several issues with the pen-and-paper development. We discuss the extent to which these issues can be fixed, and conclude with some considerations on the need for more formal verification of research results.