Year: 2022
Type: preprint
Abstract: Session types enable the specification and verification of communicating systems. However, their theory often assumes that processes never fail. To address this limitation, we present a generalised multiparty session type (MPST) theory with crash-stop failures, where processes can crash arbitrarily. Our new theory validates more protocols and processes w.r.t. previous work. We apply minimal syntactic changes to standard session π-calculus and types: we model crashes and their handling semantically, with a generalised MPST typing system parametric on a behavioural safety property. We cover the spectrum between fully reliable and fully unreliable sessions, via optional reliability assumptions, and prove type safety and protocol conformance in the presence of crash-stop failures. Introducing crash-stop failures has non-trivial consequences: writing correct processes that handle all crash scenarios can be difficult. Yet, our generalised MPST theory allows us to tame this complexity, via model checking, to validate whether a multiparty session satisfies desired behavioural properties, e.g. deadlock-freedom or liveness, even in presence of crashes. We implement our approach using the mCRL2 model checker, and evaluate it with examples extended from the literature.
Source: arXiv (Cornell University)
Institutions: Imperial College London, Technical University of Denmark
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: green
Awards: From Data Types to Session Types---A Basis for Concurrency and Distribution, Conversation-Based Governance for Distributed Systems by Multiparty Session Types, Turtles: Protocol-Based Foundations for Distributed Multiagent Systems, Session Types for Reliable Distributed Systems (STARDUST), Border Patrol: Improving Smart Device Security through Type-Aware Systems Design, Exploiting Parallelism through Type Transformations for Hybrid Manycore Systems, POST: Protocols, Observabilities and Session Types, AppControl: Enforcing Application Behaviour through Type-Based Constraints
OpenAlex ID: W4284699167