This is an early notice about Python 3.13 which will be the main Python in Fedora 41+ (https://fedoraproject.org/wiki/Changes/Python3.13). We detected that swig sets '2to3' in one of the conditionals during its build time. 2to3 and lib2to3 will be removed from Python 3.13. Python-maint has already started testing Fedora packages with Python 3.13 alphas. We'll appreciate unblocking swig as soon as possible to enable smooth integration. Possible solutions to this issue: - (preferred) port your package to Python 3 upstream - patch the source code of the package using 2to3 and add the patch to dist git 2to3 is still present in Fedora 37, 38, 39, 40.
All Python examples and tests are written to be Python 2 and Python 3 compatible in swig 4.1. So, 2to3 is not needed to run the examples or test-suite. I missed this change in long list of changes in version 4.1.