Duplo vs QuickDup

Duplo is a free tool for locating duplicated source-code blocks in large codebases. It has built-in language support for C/C++, Java, C#, VB, GCC assembly, Ada, Erlang, TypeScript and Swift, and can also scan arbitrary text files, including for duplicates within one file. For supported languages, it can filter comments, preprocessor directives and other syntax before checking for repeated code. Files can be provided through standard input or a separate file list. Duplo produces text reports as well as JSON and XML output. The project describes XML reports as usable in continuous integration tools such as GitHub Actions and TeamCity, and links to a GitHub Actions extension that can fail a build when duplicates are found. That extension has settings for minimum duplicate lines, minimum line length and maximum files reported. Prebuilt binaries are available for Alpine Linux, macOS and Windows; it can also be built from source. Duplo is free under GNU GPL version 2 or later, and is provided without warranty.

QuickDup is a repository code clone detector that finds candidate duplicate patterns using changes in indentation and the first word on each line. It skips comments and blank lines, tokenizes source lines and uses Jaccard similarity to filter patterns below a default 75% threshold. It does not parse abstract syntax trees. Detection options include normalized-indent, word-indent, word-only and inlineable strategies. The README lists comment-prefix detection for languages including Go, C and C++, Java, JavaScript and TypeScript, C#, Python, Ruby, SQL, Lua and MATLAB. QuickDup can emit GitHub Actions annotations for inline pull request comments and restrict them to files changed against a Git reference. Results are written as machine-readable JSON in a .quickdup directory. Incremental caching is available only for the word-indent strategy; other listed strategies re-parse files on each run. The README reports processing about 100,000 lines in about 500 ms on 8 cores. QuickDup is free under the MIT License, with installers for Linux, macOS and Windows, or installation from source with Go.