scala - 阐明 Scala 中的跨版本行为

Question

我想知道这两者之间有什么区别:

addCompilerPlugin("org.typelevel" %% "kind-projector" % "0.11.3" cross CrossVersion.full)

// if your project uses multiple Scala versions, use this for cross building
addCompilerPlugin("org.typelevel" % "kind-projector" % "0.11.3" cross CrossVersion.full)

我的理解是 cross CrossVersion.full将完整的 Scala 版本添加到库中，例如

kind-project_2.13.4:0.11.3

那 %%添加 Scala 二进制版本，例如

kind-project_2.13:0.11.3

因此我不明白为什么我们需要 cross CrossVersion.full与 %和 %% .有什么不同？

Answer 1

我很确定它们是一样的。
来自 Overriding the publishing convention :

crossVersion setting can override the publishing convention:

• CrossVersion.disabled (no suffix)
• CrossVersion.binary (_)
• CrossVersion.full (_)

The default is either CrossVersion.binary or CrossVersion.diabled depending on the value of crossPaths.

来自 More about using cross-built libraries :

These are equivalent:

"a" %% "b" % "1.0"
("a" % "b" % "1.0").cross(CrossVersion.binary)

所以最终重要的是 crossVersion 的值.
为了测试 crossVersion ，我在我的 build.sbt 中创建了一个简单的任务:

lazy val getVersion = taskKey[Unit]("A simple task")
getVersion := {
  List(dep1, dep2, dep3, dep4).foreach { d =>
    val att = Seq(d.organization ,d.name ,d.revision ,d.configurations ,d.isChanging ,d.isTransitive ,d.isForce ,d.explicitArtifacts ,d.inclusions ,d.exclusions ,d.extraAttributes ,d.crossVersion ,d.branchName)
    println(att)
  }
}
lazy val dep1 = "org.typelevel" % "kind-projector" % "0.11.3" cross CrossVersion.full
lazy val dep2 = "org.typelevel" %% "kind-projector" % "0.11.3" cross CrossVersion.full
lazy val dep3 = "org.typelevel" % "kind-projector" % "0.11.3"
lazy val dep4 = "org.typelevel" %% "kind-projector" % "0.11.3"

sbt getVersion 的输出是:

List(org.typelevel, kind-projector, 0.11.3, None, false, true, false, Vector(), Vector(), Vector(), Map(), Full(, ), None)
List(org.typelevel, kind-projector, 0.11.3, None, false, true, false, Vector(), Vector(), Vector(), Map(), Full(, ), None)
List(org.typelevel, kind-projector, 0.11.3, None, false, true, false, Vector(), Vector(), Vector(), Map(), Disabled(), None)
List(org.typelevel, kind-projector, 0.11.3, None, false, true, false, Vector(), Vector(), Vector(), Map(), Binary(, ), None)

正如我们所见，所有模块都是等价的，除了 crossVersion。 , 这两个 dep1 , 和 dep2是 Full(, ) .与其他两个不同的是 Disabled()和 Binary(, ) .