Bug: Some(?) GPL2+ dependencies are reported as incompatible with a GPLv3[+] project.

[andrew-vant]

Licensecheck is reporting to me that a a GPLv2-or-later dependency is incompatible with a GPLv3-or-later project. The culprit in this case is a dependency on mutagen, but I don't know if the problem is specific to that package.

The problem is accompanied by a warning message, licensecheck.license_matrix:licenseLookup:114 - 'GNU GENERAL PUBLIC LICENSE V2' License not identified so falling back to UNKNOWN. The licensecheck package list reports mutagen's license as GNU GENERAL PUBLIC LICENSE V2;; LATER _GPLV2__, which sounds like gpl2+ but is not the same license string I get with --license gplv2+. PyPI and the project homepage both give its license as GPLv2+.

I am not sure if licensecheck is making a mistake about compatibility, or if it's misidentifying mutagen's license.

My licensecheck version is 2025.1.0. You should be able to reproduce the problem by creating a dummy gplv3+ project with a dependency on mutagen. I don't know what other packages are affected, if any.