A Decentralized Analysis of Multiparty Protocols

Protocols provide the unifying glue in concurrent and distributed software today; verifying that message-passing programs conform to such governing protocols is important but difficult. Static approaches based on multiparty session types (MPST) use protocols as types to avoid protocol violations and deadlocks in programs. An elusive problem for MPST is to ensure both protocol conformance and deadlock freedom for implementations with interleaved and delegated protocols. We address this relevant problem by proposing a decentralized analysis of multiparty session protocols for asynchronous processes with recursion. Our solution rests upon APCP, a new type system that ensures protocol conformance and deadlock freedom with respect to binary protocols. Our analysis enables the sound and complete transfer of correctness from APCP to multiparty session protocols.