gh-107995: Fix doctest collection of functools.cached_property objects

Author: tjsmart

Lib/doctest.py

@@ -94,6 +94,7 @@ def _test():
 
 import __future__
 import difflib
+import functools
 import inspect
 import linecache
 import os
@@ -1044,6 +1045,13 @@ def _find(self, tests, obj, name, module, source_lines, globs, seen):
                 if isinstance(val, (staticmethod, classmethod)):
                     val = val.__func__
 
+                # For functools.cached_property objects, val is considered
+                # to be defined in the functools module instead of the
+                # module being inspected by doctest, so we grab the underlying
+                # function instead to inspect it for doctests.
+                if isinstance(val, functools.cached_property):
+                    val = val.func
+
                 # Recurse to methods, properties, and nested classes.
                 if ((inspect.isroutine(val) or inspect.isclass(val) or
                       isinstance(val, property)) and

Lib/test/test_doctest.py

@@ -111,6 +111,14 @@ def a_classmethod_property(cls):
         """
         return cls.a_class_attribute
 
+    @functools.cached_property
+    def a_cached_property(self):
+        """
+        >>> print(SampleClass(29).get())
+        29
+        """
+        return "hello"
+
     class NestedClass:
         """
         >>> x = SampleClass.NestedClass(5)
@@ -515,6 +523,7 @@ def basics(): r"""
      3  SampleClass.NestedClass
      1  SampleClass.NestedClass.__init__
      1  SampleClass.__init__
+     1  SampleClass.a_cached_property
      2  SampleClass.a_classmethod
      1  SampleClass.a_classmethod_property
      1  SampleClass.a_property
@@ -571,6 +580,7 @@ def basics(): r"""
      3  some_module.SampleClass.NestedClass
      1  some_module.SampleClass.NestedClass.__init__
      1  some_module.SampleClass.__init__
+     1  some_module.SampleClass.a_cached_property
      2  some_module.SampleClass.a_classmethod
      1  some_module.SampleClass.a_classmethod_property
      1  some_module.SampleClass.a_property
@@ -613,6 +623,7 @@ def basics(): r"""
      3  SampleClass.NestedClass
      1  SampleClass.NestedClass.__init__
      1  SampleClass.__init__
+     1  SampleClass.a_cached_property
      2  SampleClass.a_classmethod
      1  SampleClass.a_classmethod_property
      1  SampleClass.a_property
@@ -634,6 +645,7 @@ def basics(): r"""
      0  SampleClass.NestedClass.get
      0  SampleClass.NestedClass.square
      1  SampleClass.__init__
+     1  SampleClass.a_cached_property
      2  SampleClass.a_classmethod
      1  SampleClass.a_classmethod_property
      1  SampleClass.a_property

Misc/NEWS.d/next/Library/2023-08-16-00-24-07.gh-issue-107995.TlTp5t.rst

@@ -0,0 +1 @@
+Fix :mod:`doctest` collection of :func:`functools.cached_property` objects.