How can LLM be used to reproduce bugs from the bug report for better debugging?

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This blog is written by Jeremy Rivera at KushoAI. We're building the fastest way to test your APIs. It's completely free and you can sign up here.

No one writes bug-less code 100% of the time. Debugging is a constant when it comes to software development, and even though ‘test driven development’ is an ideal and can reduce bugs, it can’t prevent them completely. Dependencies have conflicts, versions get updated, and libraries change.

Debugging is one of the most time-consuming tasks in software development. When users report bugs, the process of reproducing an issue and understanding the root cause often involves interpreting vague descriptions of an issue. These reports are typically written in normal, everyday language, making it difficult for us devs to immediately translate them into test cases that accurately reproduce the problem. Here, large language models (LLMs) like ChatGPT have emerged as promising tools to automate the process of bug reproduction and improve debugging efficiency.

The Challenge of Bug Reproduction

The primary challenge in software debugging is the need to reproduce the bug based on user-reported issues. Typically, developers manually create test cases from bug reports, a process that requires time and technical expertise. However, when bug reports lack clarity or sufficient details (this is often the case), this task becomes even more challenging. Developers must interpret the report’s semantics, translating them into code that can trigger the described bug.

The Role of LLMs in Automating Bug Reproduction

Large language models like ChatGPT, which are trained on vast amounts of text and code, have the potential to automate the creation of formal test cases from bug reports. This process begins by feeding a bug report into the LLM, which then generates a test case in a programming language—often Java, Python, or similar languages. By generating these test cases, LLMs can help developers understand the issue faster and more effectively.

A recent study explored this possibility by using ChatGPT to generate test cases for bugs from the Defects4J dataset, a collection of real-world bugs from Java software projects. The researchers provided ChatGPT with bug reports and asked it to generate Java test cases that could reproduce the described issues. The results were promising, with ChatGPT producing executable test cases for 50% of the reports and valid test cases for about 30% of them.

Key Findings: Promising Results

The study revealed that, on average, 50% of the generated test cases were executable. This means that ChatGPT was able to create syntactically correct test cases that could be compiled and run. More importantly, 59% of the executable test cases were valid, meaning they successfully triggered the bug in the software, demonstrating that ChatGPT could capture the semantics of the bug report.

These results suggest that LLMs like ChatGPT can “demystify” bug reports—translating the natural language descriptions of bugs into actionable test cases that reproduce the issue. This capability can greatly reduce the time and effort required by developers to reproduce and understand bugs, enabling them to focus more on fixing the issues rather than investigating them.

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Limitations and Future Work

Despite these promising results, there are challenges to overcome. One limitation is the variability of bug reports. Some reports are overly brief or lack critical details, which makes it harder for ChatGPT to generate accurate test cases. Additionally, while many of the generated test cases were executable, they often required minor adjustments—such as adding missing imports or fixing deprecated functions—to make them fully functional.

Further research could address these challenges by fine-tuning the LLM to handle bug reports more effectively and by exploring ways to preprocess bug reports to ensure that only the most relevant information is fed into the model. Additionally, integrating automated program repair (APR) tools with LLMs could take the process a step further, not just reproducing bugs but also suggesting potential fixes.

To Conclude

The use of LLMs such as ChatGPT for bug reproduction represents a significant leap toward automating and improving the software debugging process. By converting natural language bug reports into formal test cases, LLMs can help developers reproduce and understand bugs better, saving time and improving software quality. While there are still some limitations, the results from some recent studies show great promise for the future of LLMs in software development, and with further advancements, they could play a key role in automating not only bug reproduction but also bug fixing and program repair.

This blog is written by Jeremy Rivera at KushoAI. We're building an AI agent that tests your APIs for you. Bring in API information and watch KushoAI turn it into fully functional and exhaustive test suites in minutes.