Kotlin compilation error with spring-cloud-function 4.2.0-

[bnasslahsen]

Describe the bug
Kotlin compilation error with spring-cloud-function 4.2.0

Versions of the framework:

• Spring Boot 3.4.0
• Spring Cloud: 2024.0.0
• Kotlin: 1.9.25
• Java: 17

Sample
To reproduce:

1. Generate the project from https://start.spring.io/#!type=maven-project&language=kotlin&platformVersion=3.4.0&packaging=jar&jvmVersion=17&groupId=com.example&artifactId=demo&name=demo&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.demo&dependencies=web,cloud-function
2. unzip and compile the project:

./mvnw compile

Current behavior
Compilation error:

[ERROR] Failed to execute goal org.jetbrains.kotlin:kotlin-maven-plugin:1.9.25:compile (compile) on project springdoc-openapi-starter-common: Compilation failure
[ERROR] /opt/repository/org/springframework/cloud/spring-cloud-function-context/4.2.0/spring-cloud-function-context-4.2.0.jar!/META-INF/spring-cloud-function-context.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 2.1.0, expected version is 1.9.0.
[ERROR] -> [Help 1]

Expected behavior
No compilation error

Added minimal reproducer project just in case:
demo3.zip

[olegz]

We do not specify Kotlin version anywhere in s-c-function, so it is pulled transitively.
Yes I was able to reproduce the issue with your reproducer (thank you) and it appears that something has changed upstream (perhaps in boot) since if you upgrade cloud version to 2024.0.1-SNAPSHOT, everything compiles just fine.

Please let me know, so I can close this issue

[spencergibb]

See #1015. In my tests, I see the kotlin-maven-plugin using a 2.1.0 plugin. There might be some times it gets 2.1.0 and other times it doesn't.

[olegz]

Seems like it is indeed random, so we need to be explicit about it. . .
Thank you @spencergibb for adding it - 0a43fc9

[bnasslahsen]

Wonderful, thanks @olegz and @spencergibb!
Looking forward to 4.2.1—maybe it’ll arrive just in time for Christmas!

[johnnymo87]

Hi @olegz is there a snapshot available anywhere that contains this fix? I'm unable to upgrade to Spring Boot 3.4.x until I can get access to this fix. 🙏

[10marianosikJoz]

Hi @olegz is there a snapshot available anywhere that contains this fix? I'm unable to upgrade to Spring Boot 3.4.x until I can get access to this fix. 🙏

I have same issue.

[StefanLobbenmeierObjego]

issue seems to be introduced from 4.1.4 onwards, here is what I tested

• spring-cloud-function-context-4.1.3.jar ✅
• spring-cloud-function-context-4.1.4.jar ❌
• spring-cloud-function-context-4.1.5.jar ❌
• spring-cloud-function-context-4.2.0.jar ❌
• spring-cloud-function-context-4.2.1.jar ✅

[spencergibb]

Can you try 4.2.1?

[StefanLobbenmeierObjego]

4.2.1 works on my machine, edited my comment for clarification.

There is no version of org.springframework.cloud:spring-cloud-dependencies yet that includes that release so I had to specify the version manually

	val cloudStreamVersion = "2024.0.0"
    implementation(platform("org.springframework.cloud:spring-cloud-dependencies:$cloudStreamVersion"))
    testImplementation(platform("org.springframework.cloud:spring-cloud-dependencies:$cloudStreamVersion"))
    implementation("org.springframework.cloud:spring-cloud-function-context:4.2.1")
    implementation("org.springframework.cloud:spring-cloud-starter")
    implementation("org.springframework.cloud:spring-cloud-starter-stream-kafka")

[spencergibb]

There is no version of org.springframework.cloud:spring-cloud-dependencies yet that includes that release so I had to specify the version manually

That is correct, it was specifically released outside the release train, in part, for this issue.

[matthew-js-porter]

Are there plans to backport the fix to 4.1?