Hotswap exception when updating a route class with matching Route and RouteAlias

[Artur-]

Description of the bug

When modifying this class from a starter project

@PageTitle("Hello World")
@Route(value = "", layout = MainLayout.class)
@RouteAlias(value = "", layout = MainLayout.class)
public class HelloWorldView extends HorizontalLayout {

    private TextField name;
    private Button sayHello;

    public HelloWorldView() {
        name = new TextField("Your name29");

by changing the "name29" text, the hotswap operation does not complete but throws the following exception. As a result, the view in the browser is not updated without a manual refresh

com.vaadin.flow.server.AmbiguousRouteConfigurationException: Navigation targets must have unique routes, found navigation targets 'com.example.application.views.helloworld.HelloWorldView' and 'com.example.application.views.helloworld.HelloWorldView' with the same route.
	at com.vaadin.flow.router.internal.RouteSegment.ambigousException(RouteSegment.java:806)
	at com.vaadin.flow.router.internal.RouteSegment.ambigousTarget(RouteSegment.java:801)
	at com.vaadin.flow.router.internal.RouteSegment.setRouteTarget(RouteSegment.java:487)
	at com.vaadin.flow.router.internal.RouteSegment.addSubRoute(RouteSegment.java:458)
	at com.vaadin.flow.router.internal.RouteSegment.addSubRoute(RouteSegment.java:267)
	at com.vaadin.flow.router.internal.RouteModel.addRoute(RouteModel.java:130)
	at com.vaadin.flow.router.internal.ConfigureRoutes.setRoute(ConfigureRoutes.java:175)
	at com.vaadin.flow.router.internal.AbstractRouteRegistry.lambda$setRoute$2df6994$1(AbstractRouteRegistry.java:406)
	at com.vaadin.flow.router.internal.AbstractRouteRegistry.lambda$configureWithFullTemplate$ccc9e4ad$1(AbstractRouteRegistry.java:457)
	at com.vaadin.flow.router.internal.AbstractRouteRegistry.configure(AbstractRouteRegistry.java:120)
	at com.vaadin.flow.router.internal.AbstractRouteRegistry.configureWithFullTemplate(AbstractRouteRegistry.java:456)
	at com.vaadin.flow.router.internal.AbstractRouteRegistry.setRoute(AbstractRouteRegistry.java:404)
	at com.vaadin.flow.server.startup.ApplicationRouteRegistry.setRoute(ApplicationRouteRegistry.java:130)
	at com.vaadin.flow.router.RouteConfiguration.setAnnotatedRoute(RouteConfiguration.java:231)
	at com.vaadin.flow.router.internal.RouteUtil.lambda$updateRouteRegistry$14(RouteUtil.java:520)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
	at java.base/java.util.stream.DistinctOps$1$2.accept(DistinctOps.java:174)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
	at java.base/java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1715)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:310)
	at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:596)
	at com.vaadin.flow.router.internal.RouteUtil.lambda$updateRouteRegistry$923b90d8$1(RouteUtil.java:515)
	at com.vaadin.flow.router.internal.AbstractRouteRegistry.update(AbstractRouteRegistry.java:131)
	at com.vaadin.flow.router.internal.RouteUtil.updateRouteRegistry(RouteUtil.java:503)
	at com.vaadin.flow.router.internal.RouteRegistryHotswapper.onClassLoadEvent(RouteRegistryHotswapper.java:68)
	at com.vaadin.flow.hotswap.Hotswapper.onHotswapInternal(Hotswapper.java:194)
	at com.vaadin.flow.hotswap.Hotswapper.onHotswap(Hotswapper.java:136)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)

Expected behavior

It works

Minimal reproducible example

npm init vaadin@latest
"Debug using HotswapAgent" in IntelliJ
Modify the view

Versions

Hilla: 24.5-SNAPSHOT
Flow: 24.5-SNAPSHOT
Vaadin: 24.5-SNAPSHOT
Copilot: 24.5-SNAPSHOT
Frontend Hotswap: Disabled, using pre-built bundle
OS: aarch64 Mac OS X 14.6.1
Java: JetBrains s.r.o. 21.0.3
Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36
Java Hotswap: false
IDE Plugin: ☑ 1.0.0.eap42

[mcollovati]

Does it fail even if @Route and @RouteAlias have different paths?

[Artur-]

An excellent question, and I wonder why they have the same path. It does seem to be related to that. If I remove the route alias, there is no exception. It still does not refresh the browser but that seems to be caused by something else

[Artur-]

#19973 is the lack of update problem

[Artur-]

Does it fail even if @route and @RouteAlias have different paths?

Seems like it only fails if the paths are the same

[mcollovati]

Having the same value for route and alias seems to be invalid. Unfortunately, currently, the exception is suppressed at startup.
The route validation on startup should fail if it detects such a configuration.
Also, starter projects should be fixed to prevent generating views with conflicting annotations

[Artur-]

I will fix the starters. The real problem we are seeing seems to be #19973

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.5.0.beta2 and is also targeting the upcoming stable 24.5.0 version.

[vaadin-bot]

This ticket/PR has been released with Vaadin 23.5.7.

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.4.13.