importlib.metadata: Improve and test SimplePath protocol (#11436)

Co-authored-by: layday <layday@protonmail.com>

tests/regr_test.py

@@ -180,6 +180,8 @@ def run_testcases(
         # Avoid race conditions when reading the cache
         # (https://github.com/python/typeshed/issues/11220)
         "--no-incremental",
+        # Not useful for the test cases
+        "--disable-error-code=empty-body",
     ]
 
     if package.is_stdlib:

tests/stubtest_allowlists/py310.txt

@@ -13,7 +13,6 @@ gettext.install
 gettext.translation
 importlib._abc.Loader.exec_module  # See Lib/importlib/_abc.py. Might be defined for backwards compatibility
 importlib.abc.Finder.find_module
-importlib.metadata._meta.SimplePath.__truediv__  # See comments in the stub
 # platform.uname_result's processor field is now dynamically made to exist
 platform.uname_result.__match_args__
 platform.uname_result.__new__
@@ -26,6 +25,10 @@ typing._SpecialForm.__mro_entries__
 weakref.ProxyType.__reversed__  # Doesn't really exist
 builtins.ellipsis  # type is not exposed anywhere
 
+# Runtime definition of protocol is incorrect
+importlib.metadata._meta.SimplePath.__truediv__
+importlib.metadata._meta.SimplePath.joinpath
+
 # Modules that exist at runtime, but shouldn't be added to typeshed
 ctypes.test
 ctypes\.test\..+

tests/stubtest_allowlists/py311.txt

@@ -18,6 +18,10 @@ tkinter._VersionInfoType.__doc__
 typing.NewType.__mro_entries__
 builtins.ellipsis  # type is not exposed anywhere
 
+# Runtime definition of protocol is incorrect
+importlib.metadata._meta.SimplePath.__truediv__
+importlib.metadata._meta.SimplePath.joinpath
+
 # Modules that exist at runtime, but shouldn't be added to typeshed
 ctypes.test
 ctypes\.test\..+

tests/stubtest_allowlists/py312.txt

@@ -75,6 +75,7 @@ types.GenericAlias.__getattr__
 types.GenericAlias.__mro_entries__
 sys._monitoring  # Doesn't really exist. See comments in the stub.
 weakref.ProxyType.__reversed__  # Doesn't really exist
+importlib.metadata._meta.SimplePath.joinpath  # Incorrect runtime definition
 
 # sys attributes that are not always defined
 sys.last_exc