如何获取SBT项目所有项目依赖性的源目录

Question

我正在尝试实现一个SBT任务，该任务收集了使用项目的dependsOn方法指定的项目的所有源目录。我最终得到了这件代码：

def sourcesOfDependencies(p: Project): Def.Initialize[Task[Seq[File]]] = 
  Def.taskDyn {
    p.dependencies
     .map(dep => (sourceDirectory in dep.project).toTask.map(Seq(_)))
     .reduce((t1, t2) =>
        t1.flatMap(s1 => t2.map(s2 => s1 ++ s2).taskValue)
     )
  }
sources := Def.taskDyn { sourcesOfDependencies(myProject) }.value

至于我应该有效，但无法编译：

[error] /home/visa/src/Playtech-BIT/project/SparkDeployment.scala:57:32: The evaluation of `map` inside an anonymous function is prohibited.
[error]
[error] Problem: Task invocations inside anonymous functions are evaluated independently of whether the anonymous function is invoked or not.
[error]
[error] Solution:
[error]   1. Make `map` evaluation explicit outside of the function body if you don't care about its evaluation.
[error]   2. Use a dynamic task to evaluate `map` and pass that value as a parameter to an anonymous function.
[error]
[error]         t1.flatMap(s1 => t2.map(s2 => s1 ++ s2).taskValue)
[error]                                ^
[error] /home/visa/src/Playtech-BIT/project/SparkDeployment.scala:57:26: Illegal dynamic reference: t2
[error]         t1.flatMap(s1 => t2.map(s2 => s1 ++ s2).taskValue)
[error]                          ^
[error] /home/visa/src/Playtech-BIT/project/SparkDeployment.scala:57:39: Illegal dynamic reference: s1
[error]         t1.flatMap(s1 => t2.map(s2 => s1 ++ s2).taskValue)

任何人都可以建议如何应用拟议的解决方案吗？也许有一种更简单的方法可以实现我的目标？

Answer 1

我一直在努力解决类似问题，但终于找到了答案。

所以，您可能要做的就是定义执行复杂计算的动态任务，例如

val buildMaping: Def.Initialize[Task[Seq[Def.Initialize[(ProjectRef, Seq[Seq[File]])]]]] = {
  Def.taskDyn {
    val refs = loadedBuild.value.allProjectRefs
    val tt = refs.map(_._1).map {
      ref =>
        sourceDirectories.all(ScopeFilter(inProjects(ref)))
          .zipWith(Def.setting(ref)) { case (a, b) => b -> a }
    }
    Def.task {
      tt
    }
  }
}

因此，此buildMapping允许您获取针对其源目录的项目参考的地图。

然后以这种方式调用您的任务：

Def.task {
    val sd = settingsData.in(Global).value
    val mapping = buildMaping.value.map(_.evaluate(sd)).toMap
    val allProjectRefs = loadedBuild.value.allProjectRefs.map(_._1)
    //... now you may iterate over each project, 
    // get deps and use the mapping to resolve your values
}