I was testing against the v7.0 project and ran into surprising issues in this patch. I noticed that other patches submitted against the 7.0 project around this time were also experiencing the same error:

TypeError: TypeVar.__init__() got an unexpected keyword argument 'default':

I couldn't find a BF yet for this issue. I did some digging and it seems that the issue is with a new update pushed to the "referencing" package on PyPI – 0.36.1 was released 2 hours ago. It appears that we import the jsonschema library, which in turn imports referencing. We should perhaps consider pinning this version somewhere, but given that this is transitive (as is our import of jsonschema?), I'd appreciate if someone from Build could look into this!