# Towards an Empirical Study of Affine Types for Isolated Actors in Scala

## TL;DR

This paper explores integrating LaCasa's affine type system with Scala's Akka actors to ensure actor isolation, aiming to improve security and data-race freedom, supported by an empirical study on real-world systems.

## Contribution

It introduces a novel integration of LaCasa's type system with Akka actors and provides empirical evidence of its practical effort in existing applications.

## Key findings

- LaCasa integration can be applied to real-world Akka systems.
- Using LaCasa requires manageable effort for developers.
- The approach enhances actor isolation and security.

## Abstract

LaCasa is a type system and programming model to enforce the object capability discipline in Scala, and to provide affine types. One important application of LaCasa's type system is software isolation of concurrent processes. Isolation is important for several reasons including security and data-race freedom. Moreover, LaCasa's affine references enable efficient, by-reference message passing while guaranteeing a "deep-copy" semantics. This deep-copy semantics enables programmers to seamlessly port concurrent programs running on a single machine to distributed programs running on large-scale clusters of machines. This paper presents an integration of LaCasa with actors in Scala, specifically, the Akka actor-based middleware, one of the most widely-used actor systems in industry. The goal of this integration is to statically ensure the isolation of Akka actors. Importantly, we present the results of an empirical study investigating the effort required to use LaCasa's type system in existing open-source Akka-based systems and applications.