did anyone faced this error with the swaggerUI plu...

# ktor

[Marc]

did anyone faced this error with the swaggerUI plugin?

ERROR io.ktor.server.Application - Unhandled: GET - /swagger
java.lang.ClassCastException: class kotlinx.html.DIV cannot be cast to class kotlinx.html.CoreAttributeGroupFacade (kotlinx.html.DIV and kotlinx.html.CoreAttributeGroupFacade are in unnamed module of loader 'app')
	at io.ktor.server.plugins.swagger.SwaggerKt$swaggerUI$5$2.invokeSuspend$lambda$9(Swagger.kt:103) [...] etc

I’m not doing anything misterious, just followed the doccumentation steps 😕

[simon.vergauwen]

Hey Marc!
Seems like a dependency issue. Have you checked ./gradlew dependencies?

[Aleksei Tirman [JB]]

Can you please try to disable the development mode?

[Marc]

@simon.vergauwen the dependencies tasks is the very first thing I ran, It looks like swagger tool is using the latest html version not transitively changed. @Aleksei Tirman [JB] disabling the developer mode does not change the output 🙏🏻

[Aleksei Tirman [JB]]

Can you please share a sample project to reproduce the exception?

[Marc]

its private because it. a real project I’m working on but I have no issues on inviting you to check, would it be fine @Aleksei Tirman [JB]?

[Aleksei Tirman [JB]]

Yes, it's fine.

[Marc]

could you facilitate me your github handle please?

[Aleksei Tirman [JB]]

Stexxe

[Marc]

you should have a pending invitation already 👌🏻

[Aleksei Tirman [JB]]

What steps shall I take to reproduce the exception?

[Marc]

jus runnig the project (should be one click on the IDE) and then opening the localhost:8080/swagger should be enough

[Marc]

env variables have been defined for local development already so you should not find any issue

[Marc]

the swaggerUI is deifned in HTTP.kt

[Aleksei Tirman [JB]]

It give the following error on the server startup:

Failed to initialize pool: Connection to localhost:5434 refused

After running docker compose up it reports the following error:

Error: Database is uninitialized and superuser password is not specified.
       You must specify POSTGRES_PASSWORD to a non-empty value for the
       superuser. For example, "-e POSTGRES_PASSWORD=password" on "docker run".

       You may also use "POSTGRES_HOST_AUTH_METHOD=trust" to allow all
       connections without a password. This is *not* recommended.

       See PostgreSQL documentation about "trust":
       <https://www.postgresql.org/docs/current/auth-trust.html>

[Marc]

could you update master and try now? I refactored some env variables and forgot to update them in the script that initializes the database. it should work now

[Aleksei Tirman [JB]]

Thank you. I've reproduced the exception.

[Aleksei Tirman [JB]]

Looks like there are incompatible versions of org.jetbrains.kotlinx:kotlinx-html-jvm in the project (0.7.5 and 0.12.0). The version 0.7.5 comes from org.jetbrains.dokka:dokka-base which is a dependency of io.github.nikitok:exposed-postgis . Ktor depends on the newer version of the library 0.12.0.

[Marc]

but the dependency used by the swagger one is 0.12.0 right? we would see is downgraded in the :dependencies task otherwise

[Marc]

or am I mistaken?

[Aleksei Tirman [JB]]

That's right

[Marc]

then do you still think is this the mistake? 🤔

[Aleksei Tirman [JB]]

What do you mean by mistake?

[Marc]

the fact that we see the crash from swagger at /swagger

[Marc]

I would understand if swagger fails because its somehow using the version 0.7.5 but it looks its using the correct one (0.12.0)

[Aleksei Tirman [JB]]

You're right. The only version used at runtime is 0.12.0. The problem is in the features/propertyscrapper/jars/skrapit-shadowed.jar which contains a different version of the kotlinx-html library (krapit-shadowed.jar!/kotlinx/html ). No exception is thrown without that JAR in the classpath.

[Marc]

fortunately this is a library that i had to cerate to shadow ktor xD so i can shadow html as well, hahah. let me try

[Marc]

thank you very much for the help. very insightful indeed. 🤘🏻

[Marc]

I confirm it worked. thanks for helping out troubleshooting it. And sorry for opening a question that was my fault 😅