Duplicate key detected in ClientRouteRegistry

[mshabarov]

Describe the bug

I randomly get the runtime exception about duplicate key when Hilla tries to get all routes from ClientRouteRegistry:

java.lang.IllegalArgumentException: duplicate key: /about
        at java.base/java.util.ImmutableCollections$MapN.<init>(ImmutableCollections.java:1196) ~[na:na]
        at java.base/java.util.Map.ofEntries(Map.java:1680) ~[na:na]
        at java.base/java.util.Map.copyOf(Map.java:1748) ~[na:na]
        at com.vaadin.hilla.route.ClientRouteRegistry.getAllRoutes(ClientRouteRegistry.java:67) ~[hilla-endpoint-24.4.0.alpha21.jar:na]
        at com.vaadin.hilla.route.RouteUnifyingIndexHtmlRequestListener.collectClientViews(RouteUnifyingIndexHtmlRequestListener.java:115) ~[hilla-endpoint-24.4.0.alpha21.jar:na]
        at com.vaadin.hilla.route.RouteUnifyingIndexHtmlRequestListener.modifyIndexHtmlResponse(RouteUnifyingIndexHtmlRequestListener.java:82) ~[hilla-endpoint-24.4.0.alpha21.jar:na]

This prevents application to start.
Happens in both dev and prod modes, but quite randomly.

Expected-behavior

No duplicates in routes and no exception on startup.

Reproduction

This can be reproduced with the branch vaadin/flow-hilla-hybrid-example#29.

Download the starter, checkout the branch and start with mvn (or in production mode mvn spring-boot:run -Pproduction).

Reproduces randomly locally and in GHA. You need to try several times.

System Info

Vaadin 24.4.0.alpha21, Hilla 24.4.0.alpha21

[cromoteca]

@mshabarov do you remember if this happens at startup or when making changes? I haven't been able to see it yet.

[mshabarov]

I couldn't reproduce this issue anymore after removing the legacy views.ts.
However, it's unclear how this could help.
As we discussed with @taefi , it makes sense to:

• use ConcurrentHashMap or such for registeredRoutes in ClientRouteRegistry or better
• use synchronized for registerClientRoutes in RouteUnifyingIndexHtmlRequestListener and set lastUpdated as volatile, which makes it visible and eliminates registering routes concurrently.

[mshabarov]

@mshabarov do you remember if this happens at startup or when making changes? I haven't been able to see it yet.

it happened to me in different two cases:

• when starting an app in dev mode with mvn
• when running IT tests in prod mode with mvn verify -Pit,production

Also happened several times in GHA when IT were running in prod mode.

[mshabarov]

UPD: could reproduce it again with mvn verify -Pit,production

[cromoteca]

I can't. Did you update your local branch to include my commit?

[mshabarov]

Yes.