Debugging Program Verification Proof Scripts (Tool Paper)

TL;DR

This paper introduces an offline, replay debugger for proof scripts in interactive program verification, aiding users in analyzing and debugging proof attempts more effectively, based on software debugging principles.

Contribution

It presents a novel debugger tool for proof scripts that adapts software debugging techniques to improve proof analysis in verification systems.

Findings

Supports proof script analysis and debugging

Built on top of KeY for Java program verification

Designed to be adaptable to other provers

Abstract

Interactive program verification is characterized by iterations of unfinished proof attempts. To support the process of constructing a complete proof, many interactive program verification systems offer a proof scripting language as a text-based way to describe the non-automatic steps in a proof. Such scripting languages are beneficial, but users spent a lot of effort on inspecting proof scripts and the proofs they construct to detect the cause when a proof attempt is unsuccessful and leads to unintended proof states. We present an offline and replay debugger to support the user in analyzing proof attempts performed with proof scripts. This debugger adapts successful concepts from software debugging to the area of proof script debugging. The tool is built on top of KeY, a system for deductive verification of Java programs. The debugger and its graphical user interface are designed to support program verification in particular, the underlying concepts and the implementation, however, are adaptable to other provers and proof tasks.