Error downloading ch.epfl.lamp:sbt-dotty;sbtVersion=1.0;scalaVersion=3.0.0-M2:0.4.6

[dejvid]

I have very simple sbt project and can't get it run. What can I do? What am I doing wrong?

sbt version is 1.4.4

This is build.sbt

val dottyVersion = "3.0.0-M2"

lazy val root = project
  .in(file("."))
  .settings(
    name := "dotty-simple",
    version := "0.1.0",

    scalaVersion := dottyVersion
  )

sbt outputs the following:

/usr/lib/jvm/java-11-openjdk-amd64/bin/java -Djline.terminal=jline.UnsupportedTerminal -Dsbt.log.noformat=true -Dfile.encoding=UTF-8 -Didea.managed=true -Dfile.encoding=UTF-8 -jar /home/snet/.local/share/JetBrains/IntelliJIdea2020.3/Scala/launcher/sbt-launch.jar
[info] welcome to sbt 1.4.4 (Ubuntu Java 11.0.9.1)
[info] loading global plugins from /home/snet/.sbt/1.0/plugins
[info] loading settings for project dotty-workaround-build from plugins.sbt ...
[info] loading project definition from /home/snet/Documents/razvoj/dotty-workaround/project
[info] loading settings for project root from build.sbt,project\plugins.sbt ...
[info] set current project to dotty-simple (in build file:/home/snet/Documents/razvoj/dotty-workaround/)
[info] sbt server started at local:///home/snet/.sbt/1.0/server/026a91eb7bb819c87101/sock
[info] started sbt server
sbt:dotty-simple>
;set _root_.scala.collection.Seq(historyPath := None,shellPrompt := { _ => "" },SettingKey[_root_.scala.Option[_root_.sbt.File]]("sbtStructureOutputFile")
in _root_.sbt.Global := _root_.scala.Some(_root_.sbt.file("/tmp/sbt-structure.xml")),SettingKey[_root_.java.lang.String]("sbtStructureOptions")
in _root_.sbt.Global := "download, resolveClassifiers")
[info] Defining Global / sbtStructureOptions, Global / sbtStructureOutputFile and 1 others.
[info] The new values will be used by cleanKeepGlobs
[info] 	Run `last` for details.
[info] Reapplying settings...
[info] set current project to dotty-simple (in build file:/home/snet/Documents/razvoj/dotty-workaround/)
[info] Applying State transformations org.jetbrains.sbt.CreateTasks from /home/snet/.local/share/JetBrains/IntelliJIdea2020.3/Scala/repo/org.jetbrains/sbt-structure-extractor/scala_2.12/sbt_1.0/2020.3/jars/sbt-structure-extractor.jar
[info] Reapplying settings...
[info] set current project to dotty-simple (in build file:/home/snet/Documents/razvoj/dotty-workaround/)
[warn]
[warn] 	Note: Some unresolved dependencies have extra attributes.  Check that these dependencies exist with the requested attributes.
[warn] 		ch.epfl.lamp:sbt-dotty:0.4.6 (sbtVersion=1.0, scalaVersion=3.0.0-M2)
[warn]
[warn] 	Note: Unresolved dependencies path:
[error] stack trace is suppressed; run 'last update' for the full output
[error] stack trace is suppressed; run 'last ssExtractDependencies' for the full output
[error] (update) sbt.librarymanagement.ResolveException: Error downloading ch.epfl.lamp:sbt-dotty;sbtVersion=1.0;scalaVersion=3.0.0-M2:0.4.6
[error]   Not found
[error]   Not found
[error]   not found: /home/snet/.ivy2/local/ch.epfl.lamp/sbt-dotty/scala_3.0.0-M2/sbt_1.0/0.4.6/ivys/ivy.xml
[error]   not found: https://repo1.maven.org/maven2/ch/epfl/lamp/sbt-dotty_3.0.0-M2_1.0/0.4.6/sbt-dotty-0.4.6.pom
[error] Error downloading org.scala-lang:scala-library:3.0.0-M2
[error]   Not found
[error]   Not found
[error]   not found: /home/snet/.ivy2/local/org.scala-lang/scala-library/3.0.0-M2/ivys/ivy.xml
[error]   not found: https://repo1.maven.org/maven2/org/scala-lang/scala-library/3.0.0-M2/scala-library-3.0.0-M2.pom
[error] (ssExtractDependencies) sbt.librarymanagement.ResolveException: Error downloading ch.epfl.lamp:sbt-dotty;sbtVersion=1.0;scalaVersion=3.0.0-M2:0.4.6
[error]   Not found
[error]   Not found
[error]   not found: /home/snet/.ivy2/local/ch.epfl.lamp/sbt-dotty/scala_3.0.0-M2/sbt_1.0/0.4.6/ivys/ivy.xml
[error]   not found: https://repo1.maven.org/maven2/ch/epfl/lamp/sbt-dotty_3.0.0-M2_1.0/0.4.6/sbt-dotty-0.4.6.pom
[error] Error downloading org.scala-lang:scala-library:3.0.0-M2
[error]   Not found
[error]   Not found
[error]   not found: /home/snet/.ivy2/local/org.scala-lang/scala-library/3.0.0-M2/ivys/ivy.xml
[error]   not found: https://repo1.maven.org/maven2/org/scala-lang/scala-library/3.0.0-M2/scala-library-3.0.0-M2.pom
[error] Total time: 1 s, completed 16. dec. 2020 11:00:38
[info] shutting down sbt server

[SethTisue]

I tried to reproduce this with the given build.sbt and a project/plugins.sbt of

addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.4.6")

and I didn't get the same error.

So I suspect there is something different about what you're doing, but I don't know what.

[dejvid]

Interesting... Now that I have added this line to project/plugins.sbt

addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.4.6")

it works. Also works now with 0.5.0. So it doesn't automatically add the dotty plugin by specifying scala version to 3.0.0-M2.

Thanks for your help.

The conclusion:
So if you are running SBT from the command line you have to specify sbt-dotty plugin. But in my case, I was doing the SBT project sync with the IntelliJ idea(2020.3). So I think this issue is related to IntelliJ Idea when it syncs the sbt project and it doesn't take into account plugins.sbt while doing that. Specifying sbt-dotty plugin in IntellJ Idea project doesn't resolve this error. So I think this is not related to this project. You can close the issue.

[SethTisue]

Eventually sbt will support Scala 3 directly, without requiring an extra plugin: sbt/sbt#6080