autodoc: an imported TypeVar is not resolved (refs: sphinx-doc#8415)

So far, a TypeVar is rendered without module name. As a result, it
could not be resolved if it is imported from other modules.  This
prepends its module name and make it resolvable.

As a side effect, all of TypeVars are displayed with module name. It
should be fixed in latter step (refs: sphinx-doc#7119)

CHANGES

@@ -27,6 +27,7 @@ Features added
 * autodoc: Add ``Documenter.config`` as a shortcut to access the config object
 * autodoc: Add Optional[t] to annotation of function and method if a default
   value equal to None is set.
+* #8415: autodoc: a TypeVar imported from other module is not resolved
 * #6914: Add a new event :event:`warn-missing-reference` to custom warning
   messages when failed to resolve a cross-reference
 * #6914: Emit a detailed warning when failed to resolve a ``:ref:`` reference

sphinx/util/typing.py

@@ -261,7 +261,7 @@ def stringify(annotation: Any) -> str:
         else:
             return annotation
     elif isinstance(annotation, TypeVar):
-        return annotation.__name__
+        return '.'.join([annotation.__module__, annotation.__name__])
     elif not annotation:
         return repr(annotation)
     elif annotation is NoneType:

tests/test_util_typing.py

@@ -174,10 +174,10 @@ def test_stringify_type_hints_typevars():
     T_co = TypeVar('T_co', covariant=True)
     T_contra = TypeVar('T_contra', contravariant=True)
 
-    assert stringify(T) == "T"
-    assert stringify(T_co) == "T_co"
-    assert stringify(T_contra) == "T_contra"
-    assert stringify(List[T]) == "List[T]"
+    assert stringify(T) == "test_util_typing.T"
+    assert stringify(T_co) == "test_util_typing.T_co"
+    assert stringify(T_contra) == "test_util_typing.T_contra"
+    assert stringify(List[T]) == "List[test_util_typing.T]"
 
 
 def test_stringify_type_hints_custom_class():