[7.4.x] Fix doctest collection of `functools.cached_property` objects. (#11403)

Co-authored-by: Ronny Pfannschmidt <opensource@ronnypfannschmidt.de>

AUTHORS

@@ -374,6 +374,7 @@ Tony Narlock
 Tor Colvin
 Trevor Bekolay
 Tyler Goodlet
+Tyler Smart
 Tzu-ping Chung
 Vasily Kuznetsov
 Victor Maryama

changelog/11237.bugfix.rst

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

src/_pytest/doctest.py

@@ -1,5 +1,6 @@
 """Discover and run doctests in modules and test files."""
 import bdb
+import functools
 import inspect
 import os
 import platform
@@ -536,6 +537,25 @@ class DoctestModule(Module):
                         tests, obj, name, module, source_lines, globs, seen
                     )
 
+            if sys.version_info < (3, 13):
+
+                def _from_module(self, module, object):
+                    """`cached_property` objects are never considered a part
+                    of the 'current module'. As such they are skipped by doctest.
+                    Here we override `_from_module` to check the underlying
+                    function instead. https://github.com/python/cpython/issues/107995
+                    """
+                    if hasattr(functools, "cached_property") and isinstance(
+                        object, functools.cached_property
+                    ):
+                        object = object.func
+
+                    # Type ignored because this is a private function.
+                    return super()._from_module(module, object)  # type: ignore[misc]
+
+            else:  # pragma: no cover
+                pass
+
         if self.path.name == "conftest.py":
             module = self.config.pluginmanager._importconftest(
                 self.path,

testing/test_doctest.py

@@ -482,6 +482,27 @@ class TestDoctests:
         reprec = pytester.inline_run(p, "--doctest-modules")
         reprec.assertoutcome(failed=1)
 
+    @pytest.mark.skipif(
+        sys.version_info[:2] <= (3, 7), reason="Only Python 3.7 or less"
+    )
+    def test_doctest_cached_property(self, pytester: Pytester):
+        p = pytester.makepyfile(
+            """
+            import functools
+
+            class Foo:
+                @functools.cached_property
+                def foo(self):
+                    '''
+                    >>> assert False, "Tacos!"
+                    '''
+                    ...
+        """
+        )
+        result = pytester.runpytest(p, "--doctest-modules")
+        result.assert_outcomes(failed=1)
+        assert "Tacos!" in result.stdout.str()
+
     def test_doctestmodule_external_and_issue116(self, pytester: Pytester):
         p = pytester.mkpydir("hello")
         p.joinpath("__init__.py").write_text(