All objects should be loaded by Eval and not directly

src/org/jetbrains/eval4j/interpreter.kt

@@ -19,6 +19,7 @@ class UnsupportedByteCodeException(message: String) : RuntimeException(message)
 
 trait Eval {
     fun loadClass(classType: Type): Value
+    fun loadString(str: String): Value
     fun newInstance(classType: Type): Value
     fun checkCast(value: Value, targetType: Type): Value
     fun isInsetanceOf(value: Value, targetType: Type): Boolean
@@ -83,7 +84,7 @@ class SingleInstructionInterpreter(private val eval: Eval) : Interpreter<Value>(
                     is Float -> float(cst)
                     is Long -> long(cst)
                     is Double -> double(cst)
-                    is String -> obj(cst)
+                    is String -> eval.loadString(cst)
                     is Type -> {
                         val sort = (cst as Type).getSort()
                         when (sort) {

src/org/jetbrains/eval4j/interpreterLoop.kt

@@ -97,7 +97,7 @@ fun interpreterLoop(
                     IRETURN, LRETURN, FRETURN, DRETURN, ARETURN -> {
                         val value = frame.getStack(0)!!
                         val expectedType = Type.getReturnType(m.desc)
-                        if (value.asmType != expectedType) {
+                        if (value != NULL_VALUE && value.asmType != expectedType) {
                             assert(insnOpcode == IRETURN, "Only ints should be coerced")
 
                             val coerced = when (expectedType.getSort()) {

src/org/jetbrains/eval4j/values.kt

@@ -65,7 +65,7 @@ fun int(v: Int) = IntValue(v, Type.INT_TYPE)
 fun long(v: Long) = LongValue(v)
 fun float(v: Float) = FloatValue(v)
 fun double(v: Double) = DoubleValue(v)
-fun obj<T>(v: T, t: Type = if (v != null) Type.getType(v.javaClass) else Type.getType(javaClass<Any>())) = ObjectValue(v, t)
+//fun obj<T>(v: T, t: Type = if (v != null) Type.getType(v.javaClass) else Type.getType(javaClass<Any>())) = ObjectValue(v, t)
 
 val NULL_VALUE = ObjectValue(null, Type.getObjectType("null"))
 

test/org/jetbrains/eval4j/test/TestData.java

@@ -36,6 +36,14 @@ class TestData {
         return 2.0d;
     }
 
+    static Object returnNull() {
+        return null;
+    }
+
+    static String returnString() {
+        return "str";
+    }
+
     static int variable() {
         int i = 153;
         return i;
@@ -131,4 +139,5 @@ class TestData {
         }
         return i;
     }
+
 }

test/org/jetbrains/eval4j/test/main.kt

@@ -58,7 +58,7 @@ fun doTest(ownerClass: Class<TestData>, methodNode: MethodNode): TestCase? {
                     Type.LONG -> ValueReturned(long(result as Long))
                     Type.DOUBLE -> ValueReturned(double(result as Double))
                     Type.FLOAT -> ValueReturned(float(result as Float))
-                    Type.OBJECT -> ValueReturned(obj(result))
+                    Type.OBJECT -> ValueReturned(if (result == null) NULL_VALUE else ObjectValue(result, returnType))
                     else -> {
                         println("Unsupported result type: $returnType")
                         return null
@@ -92,6 +92,8 @@ object REFLECTION_EVAL : Eval {
     override fun loadClass(classType: Type): Value {
         throw UnsupportedOperationException()
     }
+    override fun loadString(str: String): Value = ObjectValue(str, Type.getType(javaClass<String>()))
+
     override fun newInstance(classType: Type): Value {
         throw UnsupportedOperationException()
     }