sbt testQuick遇传递依赖代码变更时不重新运行的问题

我用testQuick做TDD测试时碰到个问题，已简化成最小复现示例，怀疑是配置问题，求排查：

有三个Scala项目：tests、foo、bar，依赖关系是tests → foo → bar。修改foo的代码时，源码会重新编译，测试也会自动重新运行；但修改bar的代码（比如把返回值改成false），只有bar的源码会重新编译，测试完全没跑，输出如下：

[info] 1. Monitoring source files for testquick/tests/Test/testQuick...
[info]    Press <enter> to interrupt or '?' for more options.
[info] Build triggered by <shortened>/bar/src/main/scala/Bar.scala. Running 'tests/Test/testQuick'.
[info] compiling 1 Scala source to <shortened>/bar/target/scala-3.2.2/classes ...
[info] Passed: Total 0, Failed 0, Errors 0, Passed 0
[info] No tests to run for tests / Test / testQuick
[success] Total time: 1 s, completed May 19, 2023, 11:18:15 PM
[info] 2. Monitoring source files for testquick/tests/Test/testQuick...
[info]    Press <enter> to interrupt or '?' for more options.

测试环境：sbt 1.8.3，执行命令：
sbt "~tests/Test/testQuick"

项目配置与代码 #

build.sbt #

ThisBuild / version := "0.1.0-SNAPSHOT"
ThisBuild / scalaVersion := "3.2.2"

lazy val tests = project.dependsOn(foo).settings(
  libraryDependencies += "org.scalactic" %% "scalactic" % "3.2.16",
  libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.16" % "test"
)
lazy val foo = project.dependsOn(bar)
lazy val bar = project

tests/src/test/scala/TestSpec.scala #

import org.scalatest.*
import flatspec.*

class TestSpec extends AnyFlatSpec {
  "Foo" should "be true" in {
    assert(Foo.doFoo())
  }
}

foo/src/main/scala/Foo.scala #

object Foo {
  def doFoo(): Boolean = Bar.doBar()
}

bar/src/main/scala/Bar.scala #

object Bar {
  def doBar(): Boolean = true
}

解决方案 #

这是因为sbt的testQuick默认只会检测直接依赖的变更。tests模块直接依赖foo，所以foo变更会触发tests的测试；但bar是tests的间接依赖，默认不会被testQuick的监听逻辑识别。

有两种靠谱的解决方法：

1. 让tests直接依赖bar（语义上可能冗余，但能快速解决触发问题）
   修改build.sbt中tests项目的配置：

lazy val tests = project.dependsOn(foo, bar).settings(
  libraryDependencies += "org.scalactic" %% "scalactic" % "3.2.16",
  libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.16" % "test"
)

2. 配置watchTriggeredBy监听间接依赖变更
   在tests项目的settings里添加监听规则，让tests的测试任务感知bar的编译变更：

lazy val tests = project.dependsOn(foo).settings(
  libraryDependencies += "org.scalactic" %% "scalactic" % "3.2.16",
  libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.16" % "test",
  // 添加这行配置
  Test / watchTriggeredBy += bar / Compile / compile
)

如果暂时不想调整配置，也可以用~tests/Test/test代替testQuick，但test会运行所有测试，而testQuick只跑受影响的测试，所以更推荐前两种方法。

内容的提问来源于stack exchange，提问作者Tanju Erinmez