Even with a simple Hello program, if I add the play-json as a library dependency in the build.sbt file, I always get the an merge error when I execute the 'assembly' command in sbt (sbt-assembly plugin).
[error] stack trace is suppressed; run last assembly for the full output
[error] (assembly) deduplicate: different file contents found in the following:
[error] /home/heitor/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-annotations/2.10.1/jackson-annotations-2.10.1.jar:module-info.class
[error] /home/heitor/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-core/2.10.1/jackson-core-2.10.1.jar:module-info.class
[error] /home/heitor/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-databind/2.10.1/jackson-databind-2.10.1.jar:module-info.class
[error] /home/heitor/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.10.1/jackson-datatype-jdk8-2.10.1.jar:module-info.class
[error] /home/heitor/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.10.1/jackson-datatype-jsr310-2.10.1.jar:module-info.class
MergeApp.scala
object MergeApp extends App {
println("Hello")
}
build.sbt
name := "MergeBug"
version := "0.1"
scalaVersion := "2.13.1"
val playJsonVersion = "2.8.1"
libraryDependencies ++= Seq("com.typesafe.play" %% "play-json" % playJsonVersion)
project/build.properties
sbt.version = 1.3.8
project/plugins.sbt
addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.10")
You need to define a custom merge strategy. See https://github.com/sbt/sbt-assembly#merge-strategy
Since module-info.class files are only useful for Java 9+ modules, you can safely discard them:
assemblyMergeStrategy in assembly := {
case "module-info.class" => MergeStrategy.discard
case x =>
val oldStrategy = (assemblyMergeStrategy in assembly).value
oldStrategy(x)
}