fix: handle null constructor in NewFilledInstanceInstruction and varargs with too few args

src/main/java/com/alibaba/qlexpress4/runtime/MemberResolver.java

@@ -61,6 +61,9 @@ public static Constructor<?> resolveConstructor(Class<?> cls, Class<?>[] argType
             if (!constructor.isVarArgs()) {
                 continue;
             }
+            if (argTypes.length < constructor.getParameterTypes().length - 1) {
+                continue;
+            }
             varArgsCandidates.add(adapt2VarArgTypes(constructor.getParameterTypes(), argTypes.length));
             varArgsConstructorI.add(i);
         }
@@ -156,6 +159,9 @@ public static IMethod resolveMethod(List<? extends IMethod> methods, Class<?>[]
             if (!declaredMethod.isVarArgs()) {
                 continue;
             }
+            if (argTypes.length < declaredMethod.getParameterTypes().length - 1) {
+                continue;
+            }
             varArgsCandidates.add(adapt2VarArgTypes(declaredMethod.getParameterTypes(), argTypes.length));
             varArgsMethodI.add(i);
         }

src/main/java/com/alibaba/qlexpress4/runtime/instruction/NewFilledInstanceInstruction.java

@@ -60,6 +60,11 @@ public QResult execute(QContext qContext, QLOptions qlOptions) {
 
     private Object newInstance(QContext qContext) {
         Constructor<?> constructor = qContext.getReflectLoader().loadConstructor(newCls, new Class[0]);
+        if (constructor == null) {
+            throw errorReporter.reportFormat(QLErrorCodes.NO_SUITABLE_CONSTRUCTOR.name(),
+                QLErrorCodes.NO_SUITABLE_CONSTRUCTOR.getErrorMsg(),
+                "[]");
+        }
         try {
             return constructor.newInstance();
         }
@@ -69,7 +74,7 @@ private Object newInstance(QContext qContext) {
                 QLErrorCodes.INVOKE_CONSTRUCTOR_INNER_ERROR.getErrorMsg());
         }
         catch (Exception e) {
-            throw errorReporter.report(QLErrorCodes.INVOKE_CONSTRUCTOR_UNKNOWN_ERROR.name(),
+            throw errorReporter.report(e, QLErrorCodes.INVOKE_CONSTRUCTOR_UNKNOWN_ERROR.name(),
                 QLErrorCodes.INVOKE_CONSTRUCTOR_UNKNOWN_ERROR.getErrorMsg());
         }
     }

src/main/java/com/alibaba/qlexpress4/runtime/instruction/NewInstanceInstruction.java

@@ -68,7 +68,7 @@ private Object newObject(Constructor<?> constructor, Object[] params) {
                 QLErrorCodes.INVOKE_CONSTRUCTOR_INNER_ERROR.getErrorMsg());
         }
         catch (Exception e) {
-            throw errorReporter.report(QLErrorCodes.INVOKE_CONSTRUCTOR_UNKNOWN_ERROR.name(),
+            throw errorReporter.report(e, QLErrorCodes.INVOKE_CONSTRUCTOR_UNKNOWN_ERROR.name(),
                 QLErrorCodes.INVOKE_CONSTRUCTOR_UNKNOWN_ERROR.getErrorMsg());
         }
     }

src/test/java/com/alibaba/qlexpress4/Express4RunnerTest.java

@@ -1968,4 +1968,62 @@ public Object call(QContext qContext, Parameters parameters) {
         QLResult result = express4Runner.execute("CURRENT_TIME()", context, QLOptions.DEFAULT_OPTIONS);
         assertTrue((Long)result.getResult() > 0);
     }
+
+    @Test
+    public void testNewFilledInstanceWithNoDefaultConstructor() {
+        Express4Runner express4Runner =
+            new Express4Runner(InitOptions.builder().securityStrategy(QLSecurityStrategy.open()).build());
+
+        try {
+            express4Runner.execute(
+                "{'@class': 'com.alibaba.qlexpress4.inport.NoDefaultConstructor', 'name': 'test'}",
+                new HashMap<>(), QLOptions.DEFAULT_OPTIONS);
+            fail("Expected QLRuntimeException for class without no-arg constructor");
+        }
+        catch (QLRuntimeException e) {
+            assertTrue("Expected NO_SUITABLE_CONSTRUCTOR error but got: " + e.getMessage(),
+                e.getMessage().contains("no suitable constructor"));
+        }
+    }
+
+    @Test
+    public void testVarArgsMethodWithTooFewArgs() {
+        Express4Runner express4Runner =
+            new Express4Runner(InitOptions.builder().securityStrategy(QLSecurityStrategy.open()).build());
+
+        // Calling a varargs method with fewer arguments than required parameters should
+        // produce a meaningful error instead of ArrayIndexOutOfBoundsException
+        try {
+            express4Runner.execute("com.alibaba.qlexpress4.inport.VarArgsHelper.sum()",
+                new HashMap<>(), QLOptions.DEFAULT_OPTIONS);
+            fail("Expected QLRuntimeException for varargs method called with too few args");
+        }
+        catch (QLRuntimeException e) {
+            // Should get a method-not-found or similar error, not ArrayIndexOutOfBoundsException
+            assertFalse("Should not expose ArrayIndexOutOfBoundsException",
+                e.getMessage().contains("ArrayIndexOutOfBounds"));
+        }
+
+        // Verify normal varargs calls still work correctly
+        QLResult result1 = express4Runner.execute(
+            "com.alibaba.qlexpress4.inport.VarArgsHelper.sumAll()",
+            new HashMap<>(), QLOptions.DEFAULT_OPTIONS);
+        assertEquals(0, result1.getResult());
+
+        QLResult result2 = express4Runner.execute(
+            "com.alibaba.qlexpress4.inport.VarArgsHelper.sumAll(1, 2, 3)",
+            new HashMap<>(), QLOptions.DEFAULT_OPTIONS);
+        assertEquals(6, result2.getResult());
+
+        QLResult result3 = express4Runner.execute(
+            "com.alibaba.qlexpress4.inport.VarArgsHelper.sum(10, 1, 2, 3)",
+            new HashMap<>(), QLOptions.DEFAULT_OPTIONS);
+        assertEquals(16, result3.getResult());
+
+        // Calling with exactly the minimum required args (no varargs items) should also work
+        QLResult result4 = express4Runner.execute(
+            "com.alibaba.qlexpress4.inport.VarArgsHelper.sum(10)",
+            new HashMap<>(), QLOptions.DEFAULT_OPTIONS);
+        assertEquals(10, result4.getResult());
+    }
 }

src/test/java/com/alibaba/qlexpress4/inport/NoDefaultConstructor.java

@@ -0,0 +1,19 @@
+package com.alibaba.qlexpress4.inport;
+
+/**
+ * A test helper class that intentionally has NO no-arg constructor,
+ * used to verify that NewFilledInstanceInstruction reports a proper
+ * error instead of NullPointerException.
+ */
+public class NoDefaultConstructor {
+
+    private final String name;
+
+    public NoDefaultConstructor(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+}

src/test/java/com/alibaba/qlexpress4/inport/VarArgsHelper.java

@@ -0,0 +1,29 @@
+package com.alibaba.qlexpress4.inport;
+
+/**
+ * A test helper class with varargs methods,
+ * used to verify that MemberResolver handles varargs resolution correctly
+ * when fewer arguments than required parameters are provided.
+ */
+public class VarArgsHelper {
+
+    public static String format(String template, Object... args) {
+        return String.format(template, args);
+    }
+
+    public static int sum(int required, int... rest) {
+        int total = required;
+        for (int r : rest) {
+            total += r;
+        }
+        return total;
+    }
+
+    public static int sumAll(int... values) {
+        int total = 0;
+        for (int v : values) {
+            total += v;
+        }
+        return total;
+    }
+}