Fix: Disambiguate 'PythonNativeNull' from foreign objects.

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/TruffleCextBuiltins.java

@@ -544,7 +544,7 @@ Object doPythonNativeNull(String name, @SuppressWarnings("unused") PythonNativeN
             return result;
         }
 
-        @Specialization(guards = "isForeignObject(result)")
+        @Specialization(guards = {"isForeignObject(result)", "!isNativeNull(result)"})
         Object doForeign(String name, TruffleObject result,
                         @Cached("createBinaryProfile()") ConditionProfile isNullProfile) {
             checkFunctionResult(name, isNullProfile.profile(isNull(result)));
@@ -583,6 +583,10 @@ private boolean isNull(TruffleObject result) {
             return ForeignAccess.sendIsNull(isNullNode, result);
         }
 
+        protected static boolean isNativeNull(TruffleObject object) {
+            return object instanceof PythonNativeNull;
+        }
+
         protected static boolean isPythonObjectNativeWrapper(PythonNativeWrapper object) {
             return object instanceof PythonObjectNativeWrapper;
         }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/CExtNodes.java

@@ -218,6 +218,10 @@ protected static boolean isNativeWrapper(Object obj) {
             return obj instanceof PythonNativeWrapper;
         }
 
+        protected static boolean isNativeNull(Object object) {
+            return object instanceof PythonNativeNull;
+        }
+
         protected TruffleObject importCAPISymbol(String name) {
             TruffleObject capiLibrary = (TruffleObject) getContext().getCapiLibrary();
             if (readSymbolNode == null) {
@@ -306,7 +310,7 @@ Object runAbstractObject(PythonAbstractObject object,
             return PythonObjectNativeWrapper.wrap(object, noWrapperProfile);
         }
 
-        @Specialization(guards = {"isForeignObject(object)", "!isNativeWrapper(object)"})
+        @Specialization(guards = {"isForeignObject(object)", "!isNativeWrapper(object)", "!isNativeNull(object)"})
         Object doPythonClass(TruffleObject object) {
             return TruffleObjectNativeWrapper.wrap(object);
         }
@@ -423,10 +427,6 @@ protected static boolean isPrimitiveNativeWrapper(PythonNativeWrapper object) {
             return object instanceof PrimitiveNativeWrapper && !isMaterialized((PrimitiveNativeWrapper) object);
         }
 
-        protected static boolean isNativeNull(Object object) {
-            return object instanceof PythonNativeNull;
-        }
-
         protected boolean isForeignObject(TruffleObject obj) {
             // TODO we could probably also just use 'PGuards.isForeignObject'
             if (getClassNode == null) {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/PythonNativeNull.java

@@ -100,6 +100,13 @@ long access(PythonNativeNull obj) {
             }
 
         }
+
+        @Resolve(message = "IS_NULL")
+        public abstract static class IsNull extends Node {
+            boolean access(@SuppressWarnings("unused") PythonNativeNull obj) {
+                return true;
+            }
+        }
     }
 
 }