Known issues

Scala 3: conflict between Lightbend Telemetry and Jackson

Lightbend Telemetry’s cinnamon-opentracing-datadog module (up to and including 2.22.3) is published as a plain Java artifact but declares a compile-scope dependency on the Scala 2.13 build of Jackson, com.fasterxml.jackson.module:jackson-module-scala_2.13. Because that suffix is fixed in the artifact’s POM, it is pulled regardless of the Scala version your project builds with.

On Scala 3, any project that also depends on akka-serialization-jackson (directly or transitively) pulls jackson-module-scala_3, so both cross-version variants of the module end up on the classpath:

• with sbt, resolution fails with Conflicting cross-version suffixes in: com.fasterxml.jackson.module:jackson-module-scala (_3, _2.13);
• with Maven and Gradle, the build succeeds but ships both jackson-module-scala_2.13 and jackson-module-scala_3, which is a latent runtime hazard.

Only the cinnamon-opentracing-datadog module is affected — every other Lightbend Telemetry module resolves cleanly on Scala 3. A fix is being tracked in Lightbend Telemetry.

Workaround

Until a fixed Lightbend Telemetry release is available, exclude the Scala 2.13 Jackson module from cinnamon-opentracing-datadog in your own build. This is safe on Scala 3: akka-serialization-jackson already provides jackson-module-scala_3.

sbt

("com.lightbend.cinnamon" % "cinnamon-opentracing-datadog" % cinnamonVersion)
  .exclude("com.fasterxml.jackson.module", "jackson-module-scala_2.13")

Maven

<dependency>
  <groupId>com.lightbend.cinnamon</groupId>
  <artifactId>cinnamon-opentracing-datadog</artifactId>
  <version>${cinnamon.version}</version>
  <exclusions>
    <exclusion>
      <groupId>com.fasterxml.jackson.module</groupId>
      <artifactId>jackson-module-scala_2.13</artifactId>
    </exclusion>
  </exclusions>
</dependency>

Gradle

implementation("com.lightbend.cinnamon:cinnamon-opentracing-datadog:${cinnamonVersion}") {
    exclude group: "com.fasterxml.jackson.module", module: "jackson-module-scala_2.13"
}