SpelEvaluationException: EL1012E: Cannot index into a null value in @Payload for @MessagingGateway

[tompson]

In what version(s) of Spring Integration are you seeing this issue?

6.0.2

Describe the bug

I defined a Gateway

@MessagingGateway(defaultRequestChannel = "removeTokenPubSubChannel")
public interface RemoveTokenGateway {

	@Payload("#args[0]")
	void removeToken(@Header("token") String token);
}

which worked in 5.5.16 before upgrading to Spring Boot 3

No I get

org.springframework.expression.spel.SpelEvaluationException: EL1012E: Cannot index into a null value
	at org.springframework.expression.spel.ast.Indexer.getValueRef(Indexer.java:145) ~[spring-expression-6.0.4.jar:6.0.4]
	at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:70) ~[spring-expression-6.0.4.jar:6.0.4]
	at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:91) ~[spring-expression-6.0.4.jar:6.0.4]
	at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:112) ~[spring-expression-6.0.4.jar:6.0.4]
	at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:338) ~[spring-expression-6.0.4.jar:6.0.4]
	at org.springframework.integration.gateway.GatewayMethodInboundMessageMapper$DefaultMethodArgsMessageMapper.toMessage(GatewayMethodInboundMessageMapper.java:288) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayMethodInboundMessageMapper$DefaultMethodArgsMessageMapper.toMessage(GatewayMethodInboundMessageMapper.java:275) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayMethodInboundMessageMapper.mapArgumentsToMessage(GatewayMethodInboundMessageMapper.java:193) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayMethodInboundMessageMapper.toMessage(GatewayMethodInboundMessageMapper.java:187) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayMethodInboundMessageMapper.toMessage(GatewayMethodInboundMessageMapper.java:86) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.support.converter.SimpleMessageConverter.toMessage(SimpleMessageConverter.java:111) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.doConvert(AbstractMessageSendingTemplate.java:182) ~[spring-messaging-6.0.4.jar:6.0.4]
	at org.springframework.integration.gateway.MessagingGatewaySupport$ConvertingMessagingTemplate.doConvert(MessagingGatewaySupport.java:1007) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:150) ~[spring-messaging-6.0.4.jar:6.0.4]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:143) ~[spring-messaging-6.0.4.jar:6.0.4]
	at org.springframework.integration.gateway.MessagingGatewaySupport.send(MessagingGatewaySupport.java:467) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayProxyFactoryBean.sendOrSendAndReceive(GatewayProxyFactoryBean.java:669) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayProxyFactoryBean.invokeGatewayMethod(GatewayProxyFactoryBean.java:584) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayProxyFactoryBean.doInvoke(GatewayProxyFactoryBean.java:550) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.integration.gateway.GatewayProxyFactoryBean.invoke(GatewayProxyFactoryBean.java:540) ~[spring-integration-core-6.0.2.jar:6.0.2]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.4.jar:6.0.4]
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:218) ~[spring-aop-6.0.4.jar:6.0.4]
	at jdk.proxy2/jdk.proxy2.$Proxy72.removeToken(Unknown Source) ~[na:na]

[artembilan]

Hi, @tompson !

Sad to hear that something is broken for you, but I'm sorry, what is your expectation with that #args[0] expression against your String token?
Even if that worked before, it doesn't mean that it was correct.
Either way it is more Spring Framework question since SpEL is hosted and supported over there: nothing what Spring Integration can do for you.

Thanks

[tompson]

thanks for the quick reply

since there are sample in the Spring Integration documentation it should work that way: https://docs.spring.io/spring-integration/docs/6.0.2/reference/html/messaging-endpoints.html#mapping-method-arguments

public interface MyGateway {

    void payloadAndHeaderMapWithoutAnnotations(String s, Map<String, Object> map);

    void payloadAndHeaderMapWithAnnotations(@Payload String s, @Headers Map<String, Object> map);

    void headerValuesAndPayloadWithAnnotations(@Header("k1") String x, @Payload String s, @Header("k2") String y);

    void mapOnly(Map<String, Object> map); // the payload is the map and no custom headers are added

    void twoMapsAndOneAnnotatedWithPayload(@Payload Map<String, Object> payload, Map<String, Object> headers);

    @Payload("#args[0] + #args[1] + '!'")
    void payloadAnnotationAtMethodLevel(String a, String b);

    @Payload("@someBean.exclaim(#args[0])")
    void payloadAnnotationAtMethodLevelUsingBeanResolver(String s);

    void payloadAnnotationWithExpression(@Payload("toUpperCase()") String s);

    void payloadAnnotationWithExpressionUsingBeanResolver(@Payload("@someBean.sum(#this)") String s); //  (1)

    // invalid
    void twoMapsWithoutAnnotations(Map<String, Object> m1, Map<String, Object> m2);

    // invalid
    void twoPayloads(@Payload String s1, @Payload String s2);

    // invalid
    void payloadAndHeaderAnnotationsOnSameParameter(@Payload @Header("x") String s);

    // invalid
    void payloadAndHeadersAnnotationsOnSameParameter(@Payload @Headers Map<String, Object> map);

}

[artembilan]

Oh! I see. Sorry.
I missed the fact that error is not about a [0] index for the value, but exactly about missed #args variable in the SpEL context.
Yes, that docs has to be fixed.
The current behavior is this:

@Payload("args[0]")

We now just set a root evaluation object as a MethodArgsHolder for better performance.

[tompson]

@artembilan Thanks - @Payload("args[0]") works!