[GR-21265] In EmulateJython mode isinstance function should behave in different way.

Author: ppisl

graalpython/com.oracle.graal.python.test/src/tests/test_interop.py

@@ -490,3 +490,9 @@ def test_java_null_is_none():
             assert (x is z) == False
             assert x is not z
 
+    def test_isinstance():
+        if sys.graal_python_jython_emulation_enabled:
+            import java.lang.Integer as Integer
+            i = Integer(1)
+            assert isinstance(i, Integer)
+        

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

@@ -1056,6 +1056,8 @@ public abstract static class IsInstanceNode extends PythonBinaryBuiltinNode {
         @Child private SequenceStorageNodes.LenNode lenNode;
         @Child private GetObjectArrayNode getObjectArrayNode;
 
+        @CompilationFinal private Boolean emulateJython;
+
         public static IsInstanceNode create() {
             return BuiltinFunctionsFactory.IsInstanceNodeFactory.create();
         }
@@ -1101,8 +1103,20 @@ boolean isInstance(VirtualFrame frame, Object instance, PTuple clsTuple,
             return false;
         }
 
+        protected boolean emulateJython() {
+            if (emulateJython == null) {
+                CompilerDirectives.transferToInterpreterAndInvalidate();
+                emulateJython = PythonOptions.getFlag(getContext(), PythonOptions.EmulateJython);
+            }
+            return emulateJython;
+        }
+
         @Fallback
         boolean isInstance(VirtualFrame frame, Object instance, Object cls) {
+            if (emulateJython() && getContext().getEnv().isHostObject(cls)) {
+                Object hostType = getContext().getEnv().asHostObject(cls);
+                return instance.getClass().isAssignableFrom((Class<?>) hostType);
+            }
             return isInstanceCheckInternal(frame, instance, cls) || typeInstanceCheckNode.executeWith(frame, cls, instance);
         }