如何在从sourceGenerators编译时修改AutoPlugin？

Question

我正在使用新的AutoPlugin机制为sbt编写代码生成插件。我需要修改sourceGenerators in Compile设置，但是当我从插件中执行它时，它还是不起作用。调用编译后，屏幕上不会打印任何内容。

但是，如果我将行sourceGenerators in Compile <+= (mySourceGenerator in Compile)移到项目的build.sbt中，那么sourceGenerators in Compile设置就会突然被修改，当我运行编译任务时，消息会被写到屏幕上。

有什么东西我错过了吗？插件的代码如下：

package net.lopezbobeda.plugin

import sbt._
import Keys._
import java.io.{ File, Writer }

object MyPlugin extends AutoPlugin {
  // by defining autoImport, the settings are automatically imported into user's `*.sbt`
  object autoImport {
    // configuration points, like the built-in `version`, `libraryDependencies`, or `compile`
    lazy val mySourceGenerator = taskKey[Seq[File]]("Generate")

    // default values for the tasks and settings
    lazy val baseXtendPluginSettings: Seq[Def.Setting[_]] = Seq(
      mySourceGenerator in Compile := {
        val s: TaskStreams = streams.value
        s.log.info("Generating! "  + sourceManaged.value)
        Nil
      },
      sourceGenerators in Compile <+= (mySourceGenerator in Compile) // if I put this line in build.sbt everything works as expected.
      )

  }

  override def trigger = allRequirements

  import autoImport._

  override val projectSettings = baseXtendPluginSettings


}

Answer 1

问题是JVM插件重置了sourceGenerators设置。解决方案只是添加：

override def requires = JvmPlugin

我在另一个问题中找到了解决办法：

How to generate sources in an sbt plugin?