fix: preserve exception cause in error handling paths

src/main/java/com/alibaba/qlexpress4/Express4Runner.java

@@ -642,7 +642,7 @@ public QCompileCache parseToDefinitionWithCache(String script) {
             return getParseFuture(script).get();
         }
         catch (Exception e) {
-            Throwable compileException = e.getCause();
+            Throwable compileException = e.getCause() != null ? e.getCause() : e;
             throw compileException instanceof QLSyntaxException ? (QLSyntaxException)compileException
                 : new RuntimeException(compileException);
         }

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

@@ -352,8 +352,9 @@ private BiFunction<ErrorReporter, Object, Supplier<Object>> getFieldUnAccessible
     public static QLRuntimeException unwrapMethodInvokeEx(ErrorReporter errorReporter, String methodName,
         Exception ex) {
         if (ex instanceof IllegalArgumentException) {
-            return errorReporter.reportFormat(QLErrorCodes.INVOKE_METHOD_WITH_WRONG_ARGUMENTS.name(),
-                String.format(QLErrorCodes.INVOKE_METHOD_WITH_WRONG_ARGUMENTS.getErrorMsg(), methodName));
+            return errorReporter.reportFormatWithCatch(ex,
+                QLErrorCodes.INVOKE_METHOD_WITH_WRONG_ARGUMENTS.name(),
+                QLErrorCodes.INVOKE_METHOD_WITH_WRONG_ARGUMENTS.getErrorMsg(), methodName);
         }
         else if (ex instanceof InvocationTargetException) {
             return errorReporter.report(((InvocationTargetException)ex).getTargetException(),

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

@@ -59,7 +59,8 @@ else if (!(mayBeIterable instanceof Iterable)) {
                 }
             }
             catch (UserDefineException e) {
-                throw errorReporter.reportFormat(QLErrorCodes.FOR_EACH_TYPE_MISMATCH.name(),
+                throw errorReporter.reportFormatWithCatch(e,
+                    QLErrorCodes.FOR_EACH_TYPE_MISMATCH.name(),
                     QLErrorCodes.FOR_EACH_TYPE_MISMATCH.getErrorMsg(),
                     itCls.getName(),
                     item == null ? "null" : item.getClass().getName());
@@ -69,7 +70,7 @@ else if (!(mayBeIterable instanceof Iterable)) {
                     throw (QLRuntimeException)t;
                 }
                 // should not run there
-                throw errorReporter.report(QLErrorCodes.FOR_EACH_UNKNOWN_ERROR.name(),
+                throw errorReporter.report(t, QLErrorCodes.FOR_EACH_UNKNOWN_ERROR.name(),
                     QLErrorCodes.FOR_EACH_UNKNOWN_ERROR.getErrorMsg());
             }
         }

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

@@ -69,7 +69,8 @@ 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 +68,8 @@ 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/main/java/com/alibaba/qlexpress4/runtime/util/ThrowUtils.java

@@ -20,10 +20,10 @@ public static QLRuntimeException wrapThrowable(Throwable t, ErrorReporter errorR
 
     public static QLRuntimeException reportUserDefinedException(ErrorReporter errorReporter, UserDefineException e) {
         if (Objects.equals(e.getType(), UserDefineException.ExceptionType.INVALID_ARGUMENT)) {
-            throw errorReporter.report(QLErrorCodes.INVALID_ARGUMENT.name(), e.getMessage());
+            throw errorReporter.report(e, QLErrorCodes.INVALID_ARGUMENT.name(), e.getMessage());
         }
         else {
-            throw errorReporter.report(QLErrorCodes.BIZ_EXCEPTION.name(), e.getMessage());
+            throw errorReporter.report(e, QLErrorCodes.BIZ_EXCEPTION.name(), e.getMessage());
         }
     }
 }

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

@@ -1852,4 +1852,36 @@ public void defaultAndSwitchAsVariable() {
             .execute("default = 1\nswitch = 2;\ndefault+switch", Collections.emptyMap(), QLOptions.DEFAULT_OPTIONS);
         assertEquals(3, result.getResult());
     }
+
+    @Test
+    public void parseToDefinitionWithCacheInvalidScriptTest() {
+        Express4Runner express4Runner = new Express4Runner(InitOptions.DEFAULT_OPTIONS);
+        try {
+            express4Runner.parseToDefinitionWithCache("invalid syntax @@#$");
+            fail("Expected QLSyntaxException for invalid script");
+        }
+        catch (QLSyntaxException e) {
+            // The exception should have meaningful error information
+            assertNotNull(e.getMessage());
+        }
+    }
+
+    @Test
+    public void methodInvokeWrongArgTypeCausePreservedTest() {
+        Express4Runner express4Runner =
+            new Express4Runner(InitOptions.builder().securityStrategy(QLSecurityStrategy.open()).build());
+        Map<String, Object> context = new HashMap<>();
+        context.put("str", "hello");
+        try {
+            // Call String.charAt with wrong argument type (passing a string instead of int)
+            express4Runner.execute("str.charAt(\"notAnInt\")", context, QLOptions.DEFAULT_OPTIONS);
+            fail("Expected QLRuntimeException for wrong argument type");
+        }
+        catch (QLRuntimeException e) {
+            Assert.assertEquals("INVOKE_METHOD_WITH_WRONG_ARGUMENTS", e.getErrorCode());
+            assertNotNull("Original IllegalArgumentException should be preserved as cause", e.getCause());
+            assertTrue("Cause should be IllegalArgumentException",
+                e.getCause() instanceof IllegalArgumentException);
+        }
+    }
 }

src/test/java/com/alibaba/qlexpress4/exception/MockErrorReporter.java

@@ -3,6 +3,6 @@
 public class MockErrorReporter implements ErrorReporter {
     @Override
     public QLRuntimeException reportFormatWithCatch(Object catchObj, String errorCode, String format, Object... args) {
-        return new QLRuntimeException(null, String.format(format, args), errorCode);
+        return new QLRuntimeException(catchObj, String.format(format, args), errorCode);
     }
 }

src/test/java/com/alibaba/qlexpress4/runtime/instruction/NewInstanceInstructionTest.java

@@ -148,4 +148,19 @@ public void varArgTest() {
         mockQContextParent.pushParameter(parentParameters);
         newInstruction.execute(mockQContextParent, QLOptions.DEFAULT_OPTIONS);
     }
+
+    @Test
+    public void exceptionCausePreservedTest() {
+        ErrorReporter errorReporter = new MockErrorReporter();
+        NewInstanceInstruction newInstruction = new NewInstanceInstruction(errorReporter, SomeInter.class, 0);
+        MockQContextParent mockQContextParent = new MockQContextParent(false);
+        try {
+            newInstruction.execute(mockQContextParent, QLOptions.DEFAULT_OPTIONS);
+            Assert.fail("Expected QLRuntimeException");
+        }
+        catch (QLRuntimeException e) {
+            Assert.assertEquals("INVOKE_CONSTRUCTOR_UNKNOWN_ERROR", e.getErrorCode());
+            Assert.assertNotNull("Original exception should be preserved as cause", e.getCause());
+        }
+    }
 }