Stop wrapped-fixture unwrapping at mock-like objects

changelog/15281.bugfix.rst

@@ -0,0 +1 @@
+Fixed excessive memory use and slow collection when a test module imports ``unittest.mock.call`` and the recursion limit has been raised, a regression in pytest 9.2.0.

src/_pytest/compat.py

@@ -234,6 +234,15 @@ def getimfunc(func):
         return func
 
 
+def _is_mocked(obj: object) -> bool:
+    """Return if an object is possibly a mock object by checking the
+    existence of a highly improbable attribute."""
+    return (
+        safe_getattr(obj, "pytest_mock_example_attribute_that_shouldnt_exist", None)
+        is not None
+    )
+
+
 def safe_getattr(object: Any, name: str, default: Any) -> Any:
     """Like getattr but return default upon any Exception or any OutcomeException.
 

src/_pytest/doctest.py

@@ -28,7 +28,7 @@
 from _pytest._code.code import TerminalRepr
 from _pytest._io import TerminalWriter
 from _pytest.approx import approx
-from _pytest.compat import safe_getattr
+from _pytest.compat import _is_mocked
 from _pytest.config import Config
 from _pytest.config.argparsing import Parser
 from _pytest.fixtures import fixture
@@ -464,15 +464,6 @@ def _check_all_skipped(test: doctest.DocTest) -> None:
         skip("all tests skipped by +SKIP option")
 
 
-def _is_mocked(obj: object) -> bool:
-    """Return if an object is possibly a mock object by checking the
-    existence of a highly improbable attribute."""
-    return (
-        safe_getattr(obj, "pytest_mock_example_attribute_that_shouldnt_exist", None)
-        is not None
-    )
-
-
 @contextmanager
 def _patch_unwrap_mock_aware() -> Generator[None]:
     """Context manager which replaces ``inspect.unwrap`` with a version

src/_pytest/fixtures.py

@@ -39,6 +39,7 @@
 from _pytest._code.code import ExceptionInfoFormatter
 from _pytest._code.code import TerminalRepr
 from _pytest._io import TerminalWriter
+from _pytest.compat import _is_mocked
 from _pytest.compat import assert_never
 from _pytest.compat import deprecated
 from _pytest.compat import get_real_func
@@ -2165,19 +2166,16 @@ def _find_wrapped_fixture_def(
         Returns the definition if found, else ``None``. Loops, excessive depth,
         and objects that raise on attribute access are treated as not found.
         """
-        # Skip mock objects to avoid false positives when traversing
-        # their wrapper chains (they have a _mock_name attribute).
-        if safe_getattr(obj, "_mock_name", None) is not None:
-            return None
-
         try:
             # unwrap is typed for callables, but we also pass descriptors
             # (classmethod/staticmethod) that expose __wrapped__/__func__.
             # Use type(...) is, not isinstance: some proxies raise on
             # isinstance via a broken __class__ (see pytest#4266).
             unwrapped = inspect.unwrap(
                 cast(Callable[..., Any], obj),
-                stop=lambda o: type(o) is FixtureFunctionDefinition,
+                # Stop at mock-like objects (e.g. unittest.mock.call) whose
+                # __wrapped__ chain never ends (#15281).
+                stop=lambda o: type(o) is FixtureFunctionDefinition or _is_mocked(o),
             )
         except Exception:
             # ValueError for wrapper loops / depth; also "evil objects"

testing/python/fixtures.py

@@ -6324,3 +6324,34 @@ def test_fixt(self, fixt):
     )
     result.stdout.fnmatch_lines(["*fixture 'fixt' not found*"])
     result.assert_outcomes(errors=1)
+
+
+def test_mock_call_with_raised_recursionlimit(pytester: Pytester) -> None:
+    """Collecting a module importing ``mock.call`` must not walk its endless
+    ``__wrapped__`` chain up to the recursion limit (#15281)."""
+    pytester.makeconftest(
+        """
+        import sys
+
+        sys.setrecursionlimit(100_000)
+        """
+    )
+    pytester.makepyfile(
+        """
+        from unittest.mock import call
+
+        def test_trivial():
+            pass
+        """
+    )
+    result = pytester.runpytest_subprocess(timeout=60)
+    result.assert_outcomes(passed=1)
+
+
+def test_find_wrapped_fixture_def_skips_mock_call(pytester: Pytester) -> None:
+    """``mock.call`` has ``_mock_name = None``; it must still be skipped."""
+    from unittest import mock
+
+    fm = pytester.getitem("def test_func(): pass").session._fixturemanager
+    assert fm._find_wrapped_fixture_def(mock.call) is None
+    assert fm._find_wrapped_fixture_def(mock.Mock()) is None

testing/test_doctest.py

@@ -7,9 +7,9 @@
 import sys
 import textwrap
 
+from _pytest.compat import _is_mocked
 from _pytest.doctest import _get_checker
 from _pytest.doctest import _is_main_py
-from _pytest.doctest import _is_mocked
 from _pytest.doctest import _is_setup_py
 from _pytest.doctest import _patch_unwrap_mock_aware
 from _pytest.doctest import DoctestItem