Fixpad++: Automated Bug Fix Verification using LLM AgentsAIware Honorable Mention Paper Award
Verifying bug fixes before patches are released to end users is a critical step in the software development lifecycle. However, this process is often manual, repetitive, and error-prone, especially for crash bugs triggered through Graphical User Interface (GUI) interactions in desktop applications. Despite recent advancements in LLM-driven software agents, existing work primarily targets bug reproduction without addressing bug fix verification, while approaches that do focus on verification rely on source code access, making them inapplicable to closed-source GUI-based desktop applications. This paper introduces Fixpad++, a framework designed to automatically verify bug fixes in the Notepad++ desktop application using LLM-powered agents. Fixpad++ employs a two-phase approach: first, a multi-modal multi-agent system interacts with the buggy version to reproduce the reported crash bug using visual parsing and LLM reasoning. Second, upon successful reproduction, a trajectory replay mechanism executes the recorded action sequence on the patched version to verify the fix. We evaluated Fixpad++ on FixPad-Bench, a new dataset of 105 evaluation instances derived from 22 real-world Notepad++ crash bugs, including correct and incorrect patches. The system achieved a reproduction success rate of 72.73% with an average time of 174.07 seconds. Among the successfully reproduced cases, Fixpad++ successfully verified correct fixes with 87.50% accuracy and detected incorrect fixes with 77.05% accuracy, outperforming OpenAI’s Computer-Using Agent (CUA). Fixpad++ demonstrates the effectiveness of specialized LLM agent architectures for automated bug fix verification in GUI-based desktop applications, offering a practical solution for automating verification workflows without requiring access to source code.