Introducing Specification-Based Data Structure Repair Using Alloy

Abstract

While several different techniques utilize specifications to check correctness of programs before they are deployed, the use of specifications in deployed software is more limited, largely taking the form of runtime checking where assertions form a basis for detecting erroneous program states and terminating erroneous executions in failures. Recent approaches [1] proposed constraint-based repair where data structure constraints are used to repair erroneous states. However, data structure constraints are too weak a form of specification for error recovery in general. We have developed a specification-based approach for data structure repair, which allows repairing erroneous executions in deployed software by repairing erroneous states. The key novelty is our support for rich behavioral specifications, such as those that relate pre-states with post-states to accurately specify expected behavior and hence to enable precise repair.