在SBT中的多模块项目中将scala非交叉发布的库隔离在单独的模块中

Question

这是一个恼人的问题，但我需要一个scala库，用于一个只为2.12发布的大型项目。理想情况下，我会将这个库隔离到它自己的模块中，这样就不会强迫整个项目处于scala 2.12中，因为最终这个项目需要在scala3中。有没有一种方法可以让多模块sbt项目允许Scala2.12项目依赖于scala3项目，或者与不同的scala版本共存？

到目前为止，这大致是我所拥有的(下面的例子实际上使用的是2.13.8，但想法应该是相同的)：

lazy val scala213 = "2.13.8"
lazy val scala212 = "2.12.15"

lazy val supportedScalaVersions = List(scala212, scala213)

val Versions = 
  new {
    val parser = "9.0.20210312"
    val catseffect = "3.3.3"
}

val commonSettings = Seq(
  scalacOptions -= "-Xfatal-warnings"
)

def full(p: Project) = p % "test->test;compile->compile"

lazy val cypherparser = (project in file("modules/cypherparser"))
  .settings(
    scalaVersion := scala212,
    crossScalaVersions := supportedScalaVersions,
    libraryDependencies ++= Seq(
      "org.opencypher" % "parser-9.0" % Versions.parser
    )
  ).dependsOn(shared)

lazy val shared = (project in file("modules/shared"))
  .settings(
    scalaVersion := scala213,
    crossScalaVersions := supportedScalaVersions,
    commonSettings,
    libraryDependencies ++= Seq(
      "org.typelevel" %% "cats-effect" % Versions.catseffect,
      "org.typelevel" %% "munit-cats-effect-3" % "1.0.7" % Test,
    )
  )

lazy val root = (project in file("."))
  .aggregate(shared, cypherparser)
  .settings(
    crossScalaVersions := Nil,
    publish / skip := false
  )

运行上面我得到

sbt.librarymanagement.ResolveException: Error downloading shared:shared_2.12:0.1.0-SNAPSHOT

Answer 1

因此，在评论讨论之后，我决定交叉构建我的共享模块，这样cypherparser就可以依赖它了。但是我发现了sbt-projectmatrix插件，并使用以下方法进行了一些实验

ThisBuild / version      := "0.1.0-SNAPSHOT"

lazy val scala213 = "2.13.8"
lazy val scala212 = "2.12.15"

val Versions = 
  new {
    val parser = "9.0.20210312"
    val catseffect = "3.3.3"
}

val commonSettings = Seq(
  scalacOptions -= "-Xfatal-warnings"
)

def full(p: Project) = p % "test->test;compile->compile"

lazy val cypherparser = (projectMatrix in file("modules/cypherparser"))
  .dependsOn(shared)
  .settings(
    libraryDependencies ++= Seq(
      "org.opencypher" % "parser-9.0" % Versions.parser
    )
  )
  .jvmPlatform(scalaVersions = Seq(scala212))

lazy val shared = (projectMatrix in file("modules/shared"))
  .settings(
    commonSettings,
    libraryDependencies ++= Seq(
      "org.typelevel" %% "cats-effect" % Versions.catseffect,
      "org.typelevel" %% "munit-cats-effect-3" % "1.0.7" % Test,
    )
  )
  .jvmPlatform(scalaVersions = Seq(scala212, scala213))

lazy val root = (project in file("."))
  // .aggregate(cypherparser)
  .aggregate(shared.projectRefs ++ cypherparser.projectRefs: _*)
  .settings(
    publish / skip := false
  )

..。我可以像我想的那样依赖shared。神奇的是，我还可以使用不同的版本来aggregate这些模块(仍然不太确定这是如何/为什么工作的，我只是遵循了文档)。注意:您不能在设置中使用scalaVersion，否则这会破坏事情--只在platform声明中声明scala版本。