DEV UI NPE when channel not configured.

[kristijan-rusu]

Describe the bug
DEV UI throws NPE when you have @incoming annotated method without input.
Expected behavior
DEV UI messaging part should not expect that everything is always connected. Throughout development it can happen to have channels which are not connected to any input.

Actual behavior
Internal server error because of NPE.
publisher is null in DevChannelInfo class.

To Reproduce

/**
 * Process event.
 */
@Incoming("bogus-channel")
public void process(Event event) {
	System.out.println(event);
}

Steps to reproduce the behavior:

1. Create incoming channel which is not configured with connector or in-memory emitter.
2. Start the application in DEV mode.
3. Open DEV UI

Environment (please complete the following information):
Environment information is not need here.

• Output of uname -a or ver: Darwin Kernel Version 20.3.0
• Output of java -version: Java version: 1.8.0_281, vendor: Oracle Corporation
• GraalVM version (if different from Java): Not applicable.
• Quarkus version or git rev: 1.12.0.Final
• Build tool (ie. output of mvnw --version or gradlew --version): Apache Maven 3.6.3

Additional context
Stack trace:

[io.qua.ver.htt.dep.dev.con.DevConsoleProcessor] (vert.x-eventloop-thread-1) Dev console request failed : java.lang.IllegalStateException: Reflection invocation error
	at io.quarkus.qute.ReflectionValueResolver.resolve(ReflectionValueResolver.java:58)
	at io.quarkus.qute.EvaluatorImpl.resolve(EvaluatorImpl.java:128)
	at io.quarkus.qute.EvaluatorImpl.resolveReference(EvaluatorImpl.java:79)
	at io.quarkus.qute.EvaluatorImpl.lambda$evaluate$0(EvaluatorImpl.java:41)
	at java.util.concurrent.CompletableFuture.uniComposeStage(CompletableFuture.java:995)
	at java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:2137)
	at java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:110)
	at io.quarkus.qute.EvaluatorImpl.evaluate(EvaluatorImpl.java:39)
	at io.quarkus.qute.ResolutionContextImpl.evaluate(ResolutionContextImpl.java:31)
	at io.quarkus.qute.ExpressionNode.resolve(ExpressionNode.java:26)
	at io.quarkus.qute.SectionNode$SectionResolutionContextImpl.execute(SectionNode.java:134)
	at io.quarkus.qute.SectionHelper$SectionResolutionContext.execute(SectionHelper.java:37)
	at io.quarkus.qute.Parser$1.resolve(Parser.java:1017)
	at io.quarkus.qute.SectionNode.resolve(SectionNode.java:34)
	at io.quarkus.qute.TemplateImpl$TemplateInstanceImpl.renderData(TemplateImpl.java:107)
	at io.quarkus.qute.TemplateImpl$TemplateInstanceImpl.renderAsync(TemplateImpl.java:90)
	at io.quarkus.qute.TemplateImpl$TemplateInstanceImpl.render(TemplateImpl.java:55)
	at io.quarkus.qute.Template.render(Template.java:109)
	at io.quarkus.vertx.http.deployment.devmode.console.DevConsole.sendMainPage(DevConsole.java:143)
	at io.quarkus.vertx.http.deployment.devmode.console.DevConsole.handle(DevConsole.java:76)
	at io.quarkus.vertx.http.deployment.devmode.console.DevConsole.handle(DevConsole.java:32)
	at io.vertx.ext.web.impl.RouteState.handleContext(RouteState.java:1038)
	at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:137)
	at io.vertx.ext.web.impl.RoutingContextWrapper.next(RoutingContextWrapper.java:176)
	at io.quarkus.vertx.http.deployment.devmode.console.FlashScopeHandler.handle(FlashScopeHandler.java:12)
	at io.quarkus.vertx.http.deployment.devmode.console.FlashScopeHandler.handle(FlashScopeHandler.java:7)
	at io.vertx.ext.web.impl.RouteState.handleContext(RouteState.java:1038)
	at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:137)
	at io.vertx.ext.web.impl.RoutingContextWrapper.next(RoutingContextWrapper.java:176)
	at io.vertx.ext.web.impl.RouterImpl.handleContext(RouterImpl.java:235)
	at io.vertx.ext.web.impl.RouteState.handleContext(RouteState.java:1038)
	at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:137)
	at io.vertx.ext.web.impl.RoutingContextImpl.next(RoutingContextImpl.java:132)
	at io.vertx.ext.web.impl.RouterImpl.handle(RouterImpl.java:54)
	at io.vertx.ext.web.impl.RouterImpl.handle(RouterImpl.java:36)
	at io.quarkus.vertx.http.deployment.devmode.console.DevConsoleProcessor$2$1.handle(DevConsoleProcessor.java:167)
	at io.quarkus.vertx.http.deployment.devmode.console.DevConsoleProcessor$2$1.handle(DevConsoleProcessor.java:164)
	at io.vertx.core.http.impl.Http1xServerConnection.handleMessage(Http1xServerConnection.java:136)
	at io.vertx.core.impl.ContextImpl.executeTask(ContextImpl.java:366)
	at io.vertx.core.impl.EventLoopContext.execute(EventLoopContext.java:43)
	at io.vertx.core.impl.ContextImpl.executeFromIO(ContextImpl.java:229)
	at io.vertx.core.net.impl.VertxHandler.channelRead(VertxHandler.java:163)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
	at io.quarkus.netty.runtime.virtual.VirtualChannel.readInbound(VirtualChannel.java:251)
	at io.quarkus.netty.runtime.virtual.VirtualChannel.doBeginRead(VirtualChannel.java:274)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.beginRead(AbstractChannel.java:843)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.read(DefaultChannelPipeline.java:1362)
	at io.netty.channel.AbstractChannelHandlerContext.invokeRead(AbstractChannelHandlerContext.java:686)
	at io.netty.channel.AbstractChannelHandlerContext.read(AbstractChannelHandlerContext.java:671)
	at io.netty.channel.DefaultChannelPipeline.read(DefaultChannelPipeline.java:1004)
	at io.netty.channel.AbstractChannel.read(AbstractChannel.java:278)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.readIfIsAutoRead(DefaultChannelPipeline.java:1422)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelActive(DefaultChannelPipeline.java:1400)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelActive(AbstractChannelHandlerContext.java:230)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelActive(AbstractChannelHandlerContext.java:216)
	at io.netty.channel.DefaultChannelPipeline.fireChannelActive(DefaultChannelPipeline.java:895)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:510)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:417)
	at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:474)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at io.quarkus.qute.MethodWrapper.getValue(MethodWrapper.java:22)
	at io.quarkus.qute.ReflectionValueResolver.resolve(ReflectionValueResolver.java:56)
	... 71 more
Caused by: java.lang.NullPointerException
	at io.quarkus.smallrye.reactivemessaging.runtime.devconsole.DevReactiveMessagingInfos$DevChannelInfo.compareTo(DevReactiveMessagingInfos.java:142)
	at io.quarkus.smallrye.reactivemessaging.runtime.devconsole.DevReactiveMessagingInfos$DevChannelInfo.compareTo(DevReactiveMessagingInfos.java:115)
	at java.util.ComparableTimSort.countRunAndMakeAscending(ComparableTimSort.java:325)
	at java.util.ComparableTimSort.sort(ComparableTimSort.java:188)
	at java.util.Arrays.sort(Arrays.java:1312)
	at java.util.Arrays.sort(Arrays.java:1506)
	at java.util.ArrayList.sort(ArrayList.java:1464)
	at java.util.Collections.sort(Collections.java:143)
	at io.quarkus.smallrye.reactivemessaging.runtime.devconsole.DevReactiveMessagingInfos$1.get(DevReactiveMessagingInfos.java:97)
	at io.quarkus.smallrye.reactivemessaging.runtime.devconsole.DevReactiveMessagingInfos$1.get(DevReactiveMessagingInfos.java:28)
	at io.quarkus.arc.impl.LazyValue.get(LazyValue.java:26)
	at io.quarkus.smallrye.reactivemessaging.runtime.devconsole.DevReactiveMessagingInfos.getChannels(DevReactiveMessagingInfos.java:112)
	... 77 more

[gsmet]

/cc @michalszynkiewicz @cescoffier

[michalszynkiewicz]

cc @mkouba :)

[mkouba]

Hm, I thought that an @Incoming method for which no matching channel exists must result in a deployment error. But that's obviously not the case. @cescoffier Is it intentional?

[gsmet]

Even if it was the case, I would try to be safe in the UI. Because if things change at some point, we won't notice it.

[cescoffier]

@mkouba it should fail, yes, but only on recent Smallrye Reactive Messaging.

[mkouba]

@mkouba it should fail, yes, but only on recent Smallrye Reactive Messaging.

I see. Anyway, the NPE should be fixed in the linked PR.