AttributeError: 'PathDistribution' object has no attribute '_normalized_name' #396

When importlib_metadata introduced the name normalization in PathDistributions starting in v4.3, it introduced a subtle incompatibility in select environments.

In particular, if a provider uses an older importlib metadata (importlib_metadata < 4.3 or importlib.metadata on Python < 3.10), and in that provider they supply PathDistributions, calls to resolve entry points will fail when any distribution doesn't have a _normalized_name attribute.

This issue was reported in several issues including:

• [BUG] vendored importlib.metadata of setuptools 60.9.0 fails with 'PathDistribution' object has no attribute '_normalized_name' pypa/setuptools#3102
• [BUG] Setuptools crashes when implementing find_distributions in a custom Finder in python 3.8 pypa/setuptools#3319
• [BUG] AttributeError: 'PathDistribution' object has no attribute '_normalized_name' with setuptools 60.9.0+ pypa/setuptools#3452

Perhaps importlib_metadata should provide a compatibility shim to honor name normalization in distributions not supplying it (or at least not crash).