Sbt 将设置放在文件中或放在多项目中的 commonSettings 中有何区别

Question

初学者问题，我有一个多项目 sbt 文件，如果我将常规设置放在文件开头，有什么区别吗？例如:

organization := "com.example"
  version := "0.0.1-SNAPSHOT"
  scalaVersion := "2.11.12"
resolvers ++= Seq(
    "Apache Development Snapshot Repository" at "https://repository.apache.org/content/repositories/snapshots/",
    "Typesafe repository" at "http://repo.typesafe.com/typesafe/releases/",

    Resolver.mavenLocal
  )
assemblyMergeStrategy in assembly := {
    case PathList("META-INF", xs @ _*) => MergeStrategy.discard
    case x => MergeStrategy.first
  }
lazy val commonSettings  = Seq(  libraryDependencies ++= commonDependencies ++ testingDependencies)
lazy val sharedProject = (project in file(...))
.settings(commonSettings: _*)
val projectA = .....dependsOn(sharedPorject)
val projectB = .....dependsOn(sharedPorject)

或者如果我把它放在通用设置中

lazy val commonSettings  = Seq(  
organization := "com.example",
  version := "0.0.1-SNAPSHOT",
  scalaVersion := "2.11.12",
resolvers ++= Seq(
    "Apache Development Snapshot Repository" at "https://repository.apache.org/content/repositories/snapshots/",
    "Typesafe repository" at "http://repo.typesafe.com/typesafe/releases/",
    Resolver.mavenLocal
  ),
assemblyMergeStrategy in assembly := {
    case PathList("META-INF", xs @ _*) => MergeStrategy.discard
    case x => MergeStrategy.first
  },
libraryDependencies ++= commonDependencies ++ testingDependencies)
lazy val sharedProject = (project in file(...))
.settings(commonSettings: _*)
val projectA = .....dependsOn(sharedPorject)
val projectB = .....dependsOn(sharedPorject)

有什么区别？

Answer 1

任何未附加到特定项目设置(即 .settings())而定义的设置都会附加到根项目。

因此代码如下

organization := "foo"

与

相同

lazy val root = (project in file(".")).settings(organization := "foo")

现在，如果您定义了一个新的子项目，例如 common 并向其中添加 organization

lazy val common = (project in file("common")).settings(organization := "bar")

只有它的值 organization 设置为 bar。

当根项目也定义了自己的组织时，这将在示例中成立。

lazy val root = (project in file(".")).settings(organization := "foo")

lazy val common = (project in file("common")).settings(organization := "bar")

使用命令 sbt“showorganization” 和 sbt“show common/organization” 可以轻松测试这一点。它将分别打印 foo 和 bar。

最后，如果您希望为所有子项目定义相同的值，请在根项目中为 ThisBuild 范围添加设置，如下例所示:

organization in ThisBuild := "foo"

lazy val common = (project in file("common")).settings(???)

或者将设置存储在Seq中并将其应用到所有子项目和根目录。这将具有与 ThisBuild 范围类似的效果，但更明确一点:

val commonSettings = Seq(organization := "foo")

lazy val root = (project in file(".")).settings(commonSettings)
lazy val common = (project in file("common")).settings(commonSettings)