The release of version 7.0 of the open-source Python library chardet has sparked controversy over whether an AI-assisted rewrite can change its original restrictive license. Maintainer Dan Blanchard used Anthropic's Claude tool to create a faster, MIT-licensed version, but original author Mark Pilgrim argues it violates the LGPL terms. The case highlights emerging legal and ethical questions in AI-generated code.
The chardet library, first developed by Mark Pilgrim in 2006 and released under the GNU Lesser General Public License (LGPL), detects character encodings in text. Dan Blanchard assumed maintenance in 2012 and last week unveiled version 7.0, describing it as a complete rewrite under the more permissive MIT license. Built with assistance from Anthropic's Claude coding tool, the update promises a 48-fold performance improvement and greater accuracy, achieved in about five days.
Blanchard aimed to make chardet suitable for inclusion in the Python standard library by addressing issues with its license, speed, and accuracy. He started with an empty repository, drafted a design document outlining the architecture, and instructed Claude to avoid basing the code on LGPL- or GPL-licensed material. After generation, Blanchard reviewed, tested, and iterated on every part without hand-writing the code.
However, a GitHub commenter using the name Mark Pilgrim contested the relicensing, claiming the new version derives from the original LGPL code despite the rewrite. "Their claim that it is a ‘complete rewrite’ is irrelevant, since they had ample exposure to the originally licensed code (i.e., this is not a ‘clean room’ implementation)," Pilgrim wrote. "Adding a fancy code generator into the mix does not somehow grant them any additional rights. I respectfully insist that they revert the project to its original license."
Blanchard acknowledged his familiarity with the prior codebase but maintained the AI output is structurally independent. Similarity analysis via JPlag showed at most 1.29 percent overlap between version 7.0 files and their predecessors, compared to up to 80 percent in earlier updates. He noted reliance on metadata files from old versions and Claude's training on public data, including possibly chardet's code, as potential complications.
The dispute has fueled broader discussions in the open-source community. Free Software Foundation Executive Director Zoë Kooyman told The Register, "There is nothing ‘clean’ about a Large Language Model which has ingested the code it is being asked to reimplement." Open-source developer Armin Ronacher argued in a blog post that discarding all original code creates a new work, likening it to the Ship of Theseus. Italian coder Salvatore “antirez” Sanfilippo suggested adapting to AI's transformative impact on software, while evangelist Bruce Perens warned of profound economic shifts, comparing it to the printing press's effects.
