added a workaround for tp_clear implementations, that do not check, that they are not the first in tp_clear's MRO

lostmsu · lostmsu · commit bc137bb4cb78 · 2021-09-22T12:19:57.000-07:00
https://bugs.python.org/issue45266
diff --git a/src/runtime/classbase.cs b/src/runtime/classbase.cs
@@ -360,21 +360,33 @@ public static void tp_dealloc(IntPtr ob)
 
         public static int tp_clear(IntPtr ob)
         {
-            ManagedType self = GetManagedObject(ob);
+            var self = (CLRObject)GetManagedObject(ob);
 
-            bool isTypeObject = Runtime.PyObject_TYPE(ob) == Runtime.PyCLRMetaType;
-            if (!isTypeObject)
-            {
-                ClearObjectDict(ob);
+            if (self.clearReentryGuard) return 0;
 
-                int baseClearResult = BaseUnmanagedClear(ob);
-                if (baseClearResult != 0)
+            // workaround for https://bugs.python.org/issue45266
+            self.clearReentryGuard = true;
+
+            try
+            {
+                bool isTypeObject = Runtime.PyObject_TYPE(ob) == Runtime.PyCLRMetaType;
+                if (!isTypeObject)
                 {
-                    return baseClearResult;
+                    int baseClearResult = BaseUnmanagedClear(ob);
+                    if (baseClearResult != 0)
+                    {
+                        return baseClearResult;
+                    }
+
+                    ClearObjectDict(ob);
                 }
+                if (self is not null) self.tpHandle = IntPtr.Zero;
+                return 0;
+            }
+            finally
+            {
+                self.clearReentryGuard = false;
             }
-            if (self is not null) self.tpHandle = IntPtr.Zero;
-            return 0;
         }
 
         static unsafe int BaseUnmanagedClear(IntPtr ob)
diff --git a/src/runtime/clrobject.cs b/src/runtime/clrobject.cs
@@ -9,10 +9,11 @@ namespace Python.Runtime
     internal class CLRObject : ManagedType
     {
         internal object inst;
+        internal bool clearReentryGuard;
 
         internal CLRObject(object ob, IntPtr tp)
         {
-            System.Diagnostics.Debug.Assert(tp != IntPtr.Zero);
+            Debug.Assert(tp != IntPtr.Zero);
             IntPtr py = Runtime.PyType_GenericAlloc(tp, 0);
 
             tpHandle = tp;
diff --git a/src/runtime/managedtype.cs b/src/runtime/managedtype.cs
@@ -145,7 +145,7 @@ internal static bool IsInstanceOfManagedType(IntPtr ob)
 
         internal static bool IsManagedType(BorrowedReference type)
         {
-            var flags = (TypeFlags)Util.ReadCLong(type.DangerousGetAddress(), TypeOffset.tp_flags);
+            var flags = PyType.GetFlags(type);
             return (flags & TypeFlags.HasClrInstance) != 0;
         }
 
diff --git a/src/runtime/pytype.cs b/src/runtime/pytype.cs
@@ -103,6 +103,12 @@ internal IntPtr GetSlot(TypeSlotID slot)
             return Exceptions.ErrorCheckIfNull(result);
         }
 
+        internal static TypeFlags GetFlags(BorrowedReference type)
+        {
+            Debug.Assert(TypeOffset.tp_flags > 0);
+            return (TypeFlags)Util.ReadCLong(type.DangerousGetAddress(), TypeOffset.tp_flags);
+        }
+
         internal static BorrowedReference GetBase(BorrowedReference type)
         {
             Debug.Assert(IsType(type));

Original file line number	Diff line number	Diff line change
`@@ -9,10 +9,11 @@ namespace Python.Runtime`
`9`	`9`	`internal class CLRObject : ManagedType`
`10`	`10`	`{`
`11`	`11`	`internal object inst;`
	`12`	`+ internal bool clearReentryGuard;`
`12`	`13`
`13`	`14`	`internal CLRObject(object ob, IntPtr tp)`
`14`	`15`	`{`
`15`		`- System.Diagnostics.Debug.Assert(tp != IntPtr.Zero);`
	`16`	`+ Debug.Assert(tp != IntPtr.Zero);`
`16`	`17`	`IntPtr py = Runtime.PyType_GenericAlloc(tp, 0);`
`17`	`18`
`18`	`19`	`tpHandle = tp;`
Original file line number	Diff line number	Diff line change
`@@ -145,7 +145,7 @@ internal static bool IsInstanceOfManagedType(IntPtr ob)`
`145`	`145`
`146`	`146`	`internal static bool IsManagedType(BorrowedReference type)`
`147`	`147`	`{`
`148`		`- var flags = (TypeFlags)Util.ReadCLong(type.DangerousGetAddress(), TypeOffset.tp_flags);`
	`148`	`+ var flags = PyType.GetFlags(type);`
`149`	`149`	`return (flags & TypeFlags.HasClrInstance) != 0;`
`150`	`150`	`}`
`151`	`151`
Original file line number	Diff line number	Diff line change
`@@ -103,6 +103,12 @@ internal IntPtr GetSlot(TypeSlotID slot)`
`103`	`103`	`return Exceptions.ErrorCheckIfNull(result);`
`104`	`104`	`}`
`105`	`105`
	`106`	`+ internal static TypeFlags GetFlags(BorrowedReference type)`
	`107`	`+ {`
	`108`	`+ Debug.Assert(TypeOffset.tp_flags > 0);`
	`109`	`+ return (TypeFlags)Util.ReadCLong(type.DangerousGetAddress(), TypeOffset.tp_flags);`
	`110`	`+ }`
	`111`	`+`
`106`	`112`	`internal static BorrowedReference GetBase(BorrowedReference type)`
`107`	`113`	`{`
`108`	`114`	`Debug.Assert(IsType(type));`