CodeQL zero to hero part 5: Debugging queries

CodeQL, a Prolog-like language used for security analysis, presents unique challenges when debugging queries, as traditional debugging techniques like stepping through code or using print statements do not apply. The blog post explores built-in CodeQL features for diagnosing and resolving query issues, such as using abstract syntax trees (AST), partial path graphs, and taint tracking, in the context of identifying vulnerabilities in the Gradio framework. Through a detailed case study involving the detection of an unsafe deserialization vulnerability, the author illustrates how to create a CodeQL database, simplify queries, evaluate predicates, and write taint steps to propagate data flows effectively. The post is part of a larger "CodeQL zero to hero" series that delves into various aspects of CodeQL, including static analysis fundamentals and security research, and encourages readers to engage with GitHub Security Lab's resources for further learning and assistance.