Fix doctest collection of functools.cached_property objects.

Author: tjsmart

AUTHORS

@@ -379,6 +379,7 @@ Tor Colvin
 Trevor Bekolay
 Tushar Sadhwani
 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 +537,21 @@ def _find(
                         tests, obj, name, module, source_lines, globs, seen
                     )
 
+        class CachedPropertyAwareDocTestFinder(MockAwareDocTestFinder):
+            def _from_module(self, module, object):
+                """Doctest code does not take into account `@cached_property`,
+                this is a hackish way to fix it. https://github.com/python/cpython/issues/107995
+
+                Wrap Doctest finder so that when it calls `_from_module` for
+                a cached_property it uses the underlying function instead of the
+                wrapped cached_property object.
+                """
+                if 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]
+
         if self.path.name == "conftest.py":
             module = self.config.pluginmanager._importconftest(
                 self.path,
@@ -555,7 +571,7 @@ def _find(
                 else:
                     raise
         # Uses internal doctest module parsing mechanism.
-        finder = MockAwareDocTestFinder()
+        finder = CachedPropertyAwareDocTestFinder()
         optionflags = get_optionflags(self)
         runner = _get_runner(
             verbose=False,

testing/test_doctest.py

@@ -482,6 +482,24 @@ def test_doctestmodule(self, pytester: Pytester):
         reprec = pytester.inline_run(p, "--doctest-modules")
         reprec.assertoutcome(failed=1)
 
+    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(