phpcpd-next vs Simian Similarity Analyzer

phpcpd-next is a free, MIT-licensed, token-based detector for copied PHP code in repositories. It targets PHP 8.4 and later and succeeds Sebastian Bergmann’s phpcpd. The default run combines Rabin-Karp exact matching with TokenBag detection for reordered code. An opt-in unified engine detects exact, renamed, gapped and reordered clones, while optional orphan mode identifies unreferenced classes, interfaces, traits, enums and functions. Results can be printed to the console or written as PMD-CPD XML, JSON and SARIF 2.1.0. Meaningful exit codes, result caching and a per-file incremental index support continuous integration; clone findings return status 1. Documented integrations include PHPUnit, an in-process headless API, framework presets and SARIF upload to GitHub Code Scanning. Installation is available through Composer as a development dependency or global package, or from source. Requirements are PHP 8.4+, ext-dom and ext-mbstring, with zero Composer runtime dependencies. Advanced engines are described as research-grade and may produce more false positives than the default set.

Simian Similarity Analyzer scans files in a repository and reports repeated blocks of text, including duplicated code. It analyzes human-readable material such as source files, markup, stylesheets, Markdown, and plain text. Listed languages range from Java, C, C++, C#, COBOL, and Python to JavaScript, TypeScript, HTML, XML, and CSS. The tool runs on the Java Virtual Machine, and its generated JAR works with JDK 8 or newer. It can run locally, from scripts, or in a build pipeline; the repository also documents Gradle integration. Results are plain text by default, with XML, YAML, and editor-friendly formats available. Settings include a duplicate-line threshold, file include and exclude patterns, language selection, and ways to ignore differences such as identifiers, strings, and numbers. The maker reports a JDK test processing over 2.4 million lines and finding more than 140,000 duplicate lines in under five seconds, with results varying by hardware, operating system, and options. Simian is free and open source under Apache License 2.0.