gh-107782: Pydoc: fall back to __text_signature__ if inspect.signature() fails (GH-107786)

It allows to show signatures which are not representable in Python,
e.g. for getattr and dict.pop.

1 files changed, 54 insertions, 0 deletions

diff --git a/Lib/test/test_pydoc.py b/Lib/test/test_pydoc.py
index 8df8b60..fe4e37d 100644
--- a/Lib/test/test_pydoc.py
+++ b/Lib/test/test_pydoc.py
@@ -1230,6 +1230,60 @@ class TestDescriptions(unittest.TestCase):
         self.assertEqual(self._get_summary_line(dict.__class_getitem__),
             "__class_getitem__(object, /) method of builtins.type instance")
 
+    def test_module_level_callable_unrepresentable_default(self):
+        self.assertEqual(self._get_summary_line(getattr),
+            "getattr(object, name, default=<unrepresentable>, /)")
+
+    def test_builtin_staticmethod_unrepresentable_default(self):
+        self.assertEqual(self._get_summary_line(str.maketrans),
+            "maketrans(x, y=<unrepresentable>, z=<unrepresentable>, /)")
+
+    def test_unbound_builtin_method_unrepresentable_default(self):
+        self.assertEqual(self._get_summary_line(dict.pop),
+            "pop(self, key, default=<unrepresentable>, /)")
+
+    def test_bound_builtin_method_unrepresentable_default(self):
+        self.assertEqual(self._get_summary_line({}.pop),
+            "pop(key, default=<unrepresentable>, /) "
+            "method of builtins.dict instance")
+
+    def test_overridden_text_signature(self):
+        class C:
+            def meth(*args, **kwargs):
+                pass
+            @classmethod
+            def cmeth(*args, **kwargs):
+                pass
+            @staticmethod
+            def smeth(*args, **kwargs):
+                pass
+        for text_signature, unbound, bound in [
+            ("($slf)", "(slf, /)", "()"),
+            ("($slf, /)", "(slf, /)", "()"),
+            ("($slf, /, arg)", "(slf, /, arg)", "(arg)"),
+            ("($slf, /, arg=<x>)", "(slf, /, arg=<x>)", "(arg=<x>)"),
+            ("($slf, arg, /)", "(slf, arg, /)", "(arg, /)"),
+            ("($slf, arg=<x>, /)", "(slf, arg=<x>, /)", "(arg=<x>, /)"),
+            ("(/, slf, arg)", "(/, slf, arg)", "(/, slf, arg)"),
+            ("(/, slf, arg=<x>)", "(/, slf, arg=<x>)", "(/, slf, arg=<x>)"),
+            ("(slf, /, arg)", "(slf, /, arg)", "(arg)"),
+            ("(slf, /, arg=<x>)", "(slf, /, arg=<x>)", "(arg=<x>)"),
+            ("(slf, arg, /)", "(slf, arg, /)", "(arg, /)"),
+            ("(slf, arg=<x>, /)", "(slf, arg=<x>, /)", "(arg=<x>, /)"),
+        ]:
+            with self.subTest(text_signature):
+                C.meth.__text_signature__ = text_signature
+                self.assertEqual(self._get_summary_line(C.meth),
+                        "meth" + unbound)
+                self.assertEqual(self._get_summary_line(C().meth),
+                        "meth" + bound + " method of test.test_pydoc.C instance")
+                C.cmeth.__func__.__text_signature__ = text_signature
+                self.assertEqual(self._get_summary_line(C.cmeth),
+                        "cmeth" + bound + " method of builtins.type instance")
+                C.smeth.__text_signature__ = text_signature
+                self.assertEqual(self._get_summary_line(C.smeth),
+                        "smeth" + unbound)
+
     @requires_docstrings
     def test_staticmethod(self):
         class X: