LHDiff: Tracking Source Code Lines to Support Software Maintenance Activities

Tracking lines across versions of a file is a necessary step for solving a number of problems during software development and maintenance. Examples include, but are not limited to, locating bug-inducing changes, tracking code fragments or vulnerable instructions across versions, co-change analysis, merging file versions, reviewing source code changes, and software evolution analysis. In this tool demonstration, we present a language-independent line-level location tracker, named LHDiff, that can be used to track lines and analyze changes in various kinds of software artifacts, ranging from source code to arbitrary text files. The tool can effectively detect changed or moved lines across versions of a file, has the ability to detect line splits, and can easily be integrated with existing version control systems. It overcomes the limitations of existing language-independent techniques and is even comparable to tools that are language dependent. In addition to describing the tool, we also describe its effectiveness in analyzing source code artifacts.