Add unqualified_typehints parameter to stringify_signature()

To make the generated function signatures simple, this adds a new
parameter `unqualified_typehints` to sphinx.util.inspect:
stringify_signature() to suppress the leading module name of
typehints.

sphinx/util/inspect.py

@@ -744,10 +744,13 @@ def evaluate(annotation: Any, globalns: Dict, localns: Dict) -> Any:
 
 
 def stringify_signature(sig: inspect.Signature, show_annotation: bool = True,
-                        show_return_annotation: bool = True) -> str:
+                        show_return_annotation: bool = True,
+                        unqualified_typehints: bool = False) -> str:
     """Stringify a Signature object.
 
     :param show_annotation: Show annotation in result
+    :param unqualified_typehints: Show annotations as unqualified
+                                  (ex. io.StringIO -> StringIO)
     """
     args = []
     last_kind = None
@@ -771,7 +774,7 @@ def stringify_signature(sig: inspect.Signature, show_annotation: bool = True,
 
         if show_annotation and param.annotation is not param.empty:
             arg.write(': ')
-            arg.write(stringify_annotation(param.annotation))
+            arg.write(stringify_annotation(param.annotation, unqualified_typehints))
         if param.default is not param.empty:
             if show_annotation and param.annotation is not param.empty:
                 arg.write(' = ')
@@ -791,7 +794,7 @@ def stringify_signature(sig: inspect.Signature, show_annotation: bool = True,
             show_return_annotation is False):
         return '(%s)' % ', '.join(args)
     else:
-        annotation = stringify_annotation(sig.return_annotation)
+        annotation = stringify_annotation(sig.return_annotation, unqualified_typehints)
         return '(%s) -> %s' % (', '.join(args), annotation)
 
 

tests/test_util_inspect.py

@@ -259,6 +259,10 @@ def test_signature_annotations():
     sig = inspect.signature(f7)
     assert stringify_signature(sig, show_return_annotation=False) == '(x: Optional[int] = None, y: dict = {})'
 
+    # unqualified_typehints is True
+    sig = inspect.signature(f7)
+    assert stringify_signature(sig, unqualified_typehints=True) == '(x: ~typing.Optional[int] = None, y: dict = {}) -> None'
+
 
 @pytest.mark.skipif(sys.version_info < (3, 8), reason='python 3.8+ is required.')
 @pytest.mark.sphinx(testroot='ext-autodoc')