Show HN: RealDiff – runtime behavior diffing for pull requests (six languages)

RealDiff is a tool that detects runtime behavior changes in pull requests by building and testing code revisions, establishing a noise baseline, and reporting behavioral differences across call trees. Unlike traditional source code review, it can identify unintended side effects of changes in areas the pull request never directly modified, such as how a refactored sorting method affected an unrelated pricing engine. The tool supports six programming languages and is demonstrated through a .NET example where a seemingly harmless refactor caused different output values in downstream components.