Move tp_clear workaround to .NET

filmor · filmor · commit ff1f874f93d0 · 2025-12-09T08:08:22.000+01:00
In Python 3.14, the objects __dict__ seems to already be half
deconstructed, leading to crashes during garbage collection.

Since gc in Python is single-threaded (I think :)), it should
be fine to have a single static for this. If that is not true,
we can always use a thread-local instead.
diff --git a/src/runtime/Native/PyIdentifier_.cs b/src/runtime/Native/PyIdentifier_.cs
@@ -13,8 +13,6 @@ static class PyIdentifier
          public static BorrowedReference __doc__ => new(f__doc__);
          static IntPtr f__class__;
          public static BorrowedReference __class__ => new(f__class__);
-         static IntPtr f__clear_reentry_guard__;
-         public static BorrowedReference __clear_reentry_guard__ => new(f__clear_reentry_guard__);
          static IntPtr f__module__;
          public static BorrowedReference __module__ => new(f__module__);
          static IntPtr f__file__;
@@ -51,7 +49,6 @@ static partial class InternString
             "__dict__",
             "__doc__",
             "__class__",
-            "__clear_reentry_guard__",
             "__module__",
             "__file__",
             "__slots__",
diff --git a/src/runtime/Native/PyIdentifier_.tt b/src/runtime/Native/PyIdentifier_.tt
@@ -7,7 +7,6 @@
         "__dict__",
         "__doc__",
         "__class__",
-        "__clear_reentry_guard__",
         "__module__",
         "__file__",
         "__slots__",
diff --git a/src/runtime/Types/ClassBase.cs b/src/runtime/Types/ClassBase.cs
@@ -374,6 +374,8 @@ public static int tp_clear(BorrowedReference ob)
             return 0;
         }
 
+        static readonly HashSet<IntPtr> ClearVisited = new();
+
         internal static unsafe int BaseUnmanagedClear(BorrowedReference ob)
         {
             var type = Runtime.PyObject_TYPE(ob);
@@ -385,26 +387,20 @@ internal static unsafe int BaseUnmanagedClear(BorrowedReference ob)
             }
             var clear = (delegate* unmanaged[Cdecl]<BorrowedReference, int>)clearPtr;
 
-            bool usesSubtypeClear = clearPtr == TypeManager.subtype_clear;
-            if (usesSubtypeClear)
+            if (clearPtr == TypeManager.subtype_clear)
             {
-                // workaround for https://bugs.python.org/issue45266 (subtype_clear)
-                using var dict = Runtime.PyObject_GenericGetDict(ob);
-                if (Runtime.PyMapping_HasKey(dict.Borrow(), PyIdentifier.__clear_reentry_guard__) != 0)
+                var addr = ob.DangerousGetAddress();
+                if (!ClearVisited.Add(addr))
                     return 0;
 
-                int res = Runtime.PyDict_SetItem(
-                    dict.Borrow(),
-                    PyIdentifier.__clear_reentry_guard__,
-                    Runtime.PyTrue
-                );
-                if (res != 0) return res;
-
-                res = clear(ob);
-                Runtime.PyDict_DelItem(dict.Borrow(), PyIdentifier.__clear_reentry_guard__);
+                int res = clear(ob);
+                ClearVisited.Remove(addr);
                 return res;
             }
-            return clear(ob);
+            else
+            {
+                return clear(ob);
+            }
         }
 
         protected override Dictionary<string, object?> OnSave(BorrowedReference ob)
diff --git a/tests/test_method.py b/tests/test_method.py
@@ -942,7 +942,6 @@ def test_getting_generic_method_binding_does_not_leak_ref_count():
     refCount = sys.getrefcount(PlainOldClass().GenericMethod[str])
     assert refCount == 1
 
-@pytest.mark.skipif(sys.version_info >= (3, 14), reason="Test skipped on Python 3.14 and above")
 def test_getting_generic_method_binding_does_not_leak_memory():
     """Test that managed object is freed after calling generic method. Issue #691"""
 
@@ -984,7 +983,6 @@ def test_getting_overloaded_method_binding_does_not_leak_ref_count():
     refCount = sys.getrefcount(PlainOldClass().OverloadedMethod.Overloads[int])
     assert refCount == 1
 
-@pytest.mark.skipif(sys.version_info >= (3, 14), reason="Test skipped on Python 3.14 and above")
 def test_getting_overloaded_method_binding_does_not_leak_memory():
     """Test that managed object is freed after calling overloaded method. Issue #691"""
 
@@ -1027,7 +1025,6 @@ def test_getting_method_overloads_binding_does_not_leak_ref_count():
     assert refCount == 1
 
 @pytest.mark.xfail(reason="Fails locally, need to investigate later", strict=False)
-@pytest.mark.skipif(sys.version_info >= (3, 14), reason="Test skipped on Python 3.14 and above")
 def test_getting_method_overloads_binding_does_not_leak_memory():
     """Test that managed object is freed after calling overloaded method. Issue #691"""
 
diff --git a/tests/test_subclass.py b/tests/test_subclass.py
@@ -304,7 +304,6 @@ def __init__(self, i, s):
     assert calls[0][1] == "foo"
 
 # regression test for https://github.com/pythonnet/pythonnet/issues/1565
-@pytest.mark.skipif(sys.version_info >= (3, 14), reason="Test skipped on Python 3.14 and above")
 def test_can_be_collected_by_gc():
     from Python.Test import BaseClass
 
