Why is the error Conflicting cross-version suffixes? - scala

Question

I'm getting this error when I try to compile a Scala project in sbt.
Modules were resolved with conflicting cross-version suffixes in {file:/home/seven3n/caja/Flujo_de_caja/}flujo_de_caja:
[error] com.typesafe.akka:akka-actor _2.11, _2.10
[error] org.scalaz:scalaz-effect _2.10, _2.11
[error] org.scalaz:scalaz-core _2.10, _2.11
[trace] Stack trace suppressed: run last *:update for the full output.
[error] (*:update) Conflicting cross-version suffixes in: com.typesafe.akka:akka-actor, org.scalaz:scalaz-effect, org.scalaz:scalaz-core
This is my build.sbt file:
scalaVersion := "2.11.0"
resolvers ++= Seq(
"Sonatype snapshots repository" at "https://oss.sonatype.org/content/repositories/snapshots/",
"Spray repository" at "http://repo.spray.io/",
"Typesafe repository" at "http://repo.typesafe.com/typesafe/releases/"
)
libraryDependencies ++= {
val akkaVersion = "2.3.2"
val sprayVersion = "1.3.1-20140423"
val sprayJsonVersion = "1.2.6"
val reactiveMongoVersion = "0.11.0-SNAPSHOT"
val scalaTestVersion = "2.1.5"
val specs2Version = "2.3.11"
val foloneVersion = "0.12-SNAPSHOT"
Seq(
"com.typesafe.akka" %% "akka-actor" % akkaVersion,
"com.typesafe.akka" %% "akka-testkit" % akkaVersion,
"io.spray" %% "spray-can" % sprayVersion,
"io.spray" %% "spray-routing" % sprayVersion,
"io.spray" %% "spray-testkit" % sprayVersion,
"io.spray" %% "spray-json" % sprayJsonVersion,
"org.reactivemongo" % "reactivemongo_2.10" % reactiveMongoVersion,
"org.scalatest" %% "scalatest" % scalaTestVersion % "test",
"org.specs2" %% "specs2" % specs2Version % "test",
"info.folone" % "poi-scala_2.10" % foloneVersion
)
}
Any suggestions?

Answer 1

The conflicts appear because:
you've specified your Scala version to be 2.11
you've explicitly specified the Scala version (2.10) for the reactivemongo and poi-scala libraries.
The fix is to use the %% operator for those two libraries as well.
"org.reactivemongo" %% "reactivemongo" % reactiveMongoVersion,
"info.folone" %% "poi-scala" % foloneVersion
That's the purpose of the %% operator. To append the declared Scala version (2.11 in your case) to the artifact name.

Answer 2

I had the same problem and I simply removed the scalaVersion tag from my sbt file and modified the line
libraryDependencies += "org.apache.spark" %% "spark-core" % "1.6.0"
to
libraryDependencies += "org.apache.spark" % "spark-core_2.11" % "1.6.0"
and the problem went away.

Answer 3

I have tried using %% but it didn't work. I have manually excluded it using
("org.reactivemongo" % "reactivemongo" % reactiveMongoVersion)
.exclude("com.typesafe.akka", "akka-actor_2.10")
.exclude("org.scalaz", "scalaz-effect")
.exclude("org.scalaz", "scalaz-core")

Answer 4

To investigate who is caller you can use a plugin but an easier way to look into target/scala-2.*/resolution-cache/reports/.
There is Ivy's resolution report for each configuration.
Look for *-compile.xml and *-test.xml and search for conflicting library.
You can see similar with
<module organisation="com.github.nscala-time" name="nscala-time_2.11">
...
<caller organisation="com.tumblr" name="colossus-metrics_2.11" conf="compile, runtime" rev="1.2.0" rev-constraint-default="1.2.0" rev-constraint-dynamic="1.2.0" callerrev="0.7.2-RC1"/>
...
</module>
This should tell you the caller of the module.