NPE when integrate with micrometer-tracing and webflux

[neo7343]

simple setup using start.spring.io setup

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.0.0'
    id 'io.spring.dependency-management' version '1.1.0'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
    implementation 'org.springframework.boot:spring-boot-starter-graphql'
    implementation 'org.springframework.boot:spring-boot-starter-webflux'
    implementation 'io.micrometer:micrometer-tracing-bridge-brave'
    implementation 'io.zipkin.reporter2:zipkin-reporter-brave'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testImplementation 'io.projectreactor:reactor-test'
    testImplementation 'org.springframework.graphql:spring-graphql-test'
}

tasks.named('test') {
    useJUnitPlatform()
}

schema

type Query {
    hello: String!
}

controller

@Controller
public class QueryController {
    @QueryMapping
    public String hello(){
        return "hello world";
    }
}

request

curl --location --request POST 'http://localhost:8080/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"{hello}"}'

then got this error

java.lang.NullPointerException: Cannot invoke "Object.toString()" because the return value of "java.util.Map.get(Object)" is null
	at org.springframework.graphql.observation.ExecutionRequestObservationContext.lambda$new$0(ExecutionRequestObservationContext.java:35) ~[spring-graphql-1.1.0.jar:1.1.0]
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	*__checkpoint ⇢ org.springframework.web.filter.reactive.ServerHttpObservationFilter [DefaultWebFilterChain]
	*__checkpoint ⇢ HTTP POST "/graphql" [ExceptionHandlingWebHandler]
Original Stack Trace:
		at org.springframework.graphql.observation.ExecutionRequestObservationContext.lambda$new$0(ExecutionRequestObservationContext.java:35) ~[spring-graphql-1.1.0.jar:1.1.0]
		at io.micrometer.tracing.handler.PropagatingReceiverTracingObservationHandler.lambda$onStart$0(PropagatingReceiverTracingObservationHandler.java:59) ~[micrometer-tracing-1.0.0.jar:1.0.0]
		at io.micrometer.tracing.brave.bridge.W3CPropagation.lambda$extractor$1(W3CPropagation.java:249) ~[micrometer-tracing-bridge-brave-1.0.0.jar:1.0.0]
		at io.micrometer.tracing.brave.bridge.BravePropagator.extract(BravePropagator.java:59) ~[micrometer-tracing-bridge-brave-1.0.0.jar:1.0.0]
		at io.micrometer.tracing.handler.PropagatingReceiverTracingObservationHandler.onStart(PropagatingReceiverTracingObservationHandler.java:58) ~[micrometer-tracing-1.0.0.jar:1.0.0]
		at io.micrometer.tracing.handler.PropagatingReceiverTracingObservationHandler.onStart(PropagatingReceiverTracingObservationHandler.java:35) ~[micrometer-tracing-1.0.0.jar:1.0.0]
		at io.micrometer.observation.ObservationHandler$FirstMatchingCompositeObservationHandler.lambda$onStart$1(ObservationHandler.java:134) ~[micrometer-observation-1.10.2.jar:1.10.2]
		at java.base/java.util.Optional.ifPresent(Optional.java:178) ~[na:na]
		at io.micrometer.observation.ObservationHandler$FirstMatchingCompositeObservationHandler.onStart(ObservationHandler.java:134) ~[micrometer-observation-1.10.2.jar:1.10.2]
		at io.micrometer.observation.SimpleObservation.lambda$notifyOnObservationStarted$2(SimpleObservation.java:188) ~[micrometer-observation-1.10.2.jar:1.10.2]
		at java.base/java.util.ArrayDeque.forEach(ArrayDeque.java:888) ~[na:na]
		at io.micrometer.observation.SimpleObservation.notifyOnObservationStarted(SimpleObservation.java:188) ~[micrometer-observation-1.10.2.jar:1.10.2]
		at io.micrometer.observation.SimpleObservation.start(SimpleObservation.java:143) ~[micrometer-observation-1.10.2.jar:1.10.2]
		at org.springframework.graphql.observation.GraphQlObservationInstrumentation.beginExecution(GraphQlObservationInstrumentation.java:105) ~[spring-graphql-1.1.0.jar:1.1.0]
		at graphql.execution.instrumentation.ChainedInstrumentation.lambda$beginExecution$0(ChainedInstrumentation.java:85) ~[graphql-java-19.2.jar:na]
		at graphql.collect.ImmutableKit.mapAndDropNulls(ImmutableKit.java:107) ~[graphql-java-19.2.jar:na]
		at graphql.execution.instrumentation.ChainedInstrumentation.beginExecution(ChainedInstrumentation.java:83) ~[graphql-java-19.2.jar:na]
		at graphql.GraphQL.executeAsync(GraphQL.java:522) ~[graphql-java-19.2.jar:na]
		at org.springframework.graphql.execution.DefaultExecutionGraphQlService.lambda$execute$2(DefaultExecutionGraphQlService.java:82) ~[spring-graphql-1.1.0.jar:1.1.0]
		at reactor.core.publisher.MonoDeferContextual.subscribe(MonoDeferContextual.java:47) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:165) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:158) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onNext(FluxContextWrite.java:107) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onNext(FluxMapFuseable.java:299) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableConditionalSubscriber.onNext(FluxFilterFuseable.java:337) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.Operators$BaseFluxToMonoOperator.completePossiblyEmpty(Operators.java:2034) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.MonoCollect$CollectSubscriber.onComplete(MonoCollect.java:145) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:144) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxPeek$PeekSubscriber.onComplete(FluxPeek.java:260) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:144) ~[reactor-core-3.5.0.jar:3.5.0]
		at reactor.netty.channel.FluxReceive.onInboundComplete(FluxReceive.java:413) ~[reactor-netty-core-1.1.0.jar:1.1.0]
		at reactor.netty.channel.ChannelOperations.onInboundComplete(ChannelOperations.java:426) ~[reactor-netty-core-1.1.0.jar:1.1.0]
		at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:603) ~[reactor-netty-http-1.1.0.jar:1.1.0]
		at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:113) ~[reactor-netty-core-1.1.0.jar:1.1.0]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.85.Final.jar:4.1.85.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.85.Final.jar:4.1.85.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.85.Final.jar:4.1.85.Final]
		at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:266) ~[reactor-netty-http-1.1.0.jar:1.1.0]

[bclozel]

Duplicates #547