Extract Mill plugins also from build.mill{,.scala} files (#3537)

Author: fthomas

modules/core/src/main/scala/org/scalasteward/core/buildtool/mill/MillAlg.scala

@@ -36,14 +36,12 @@ final class MillAlg[F[_]](defaultResolver: Resolver)(implicit
   override def name: String = "Mill"
 
   override def containsBuild(buildRoot: BuildRoot): F[Boolean] =
-    workspaceAlg
-      .buildRootDir(buildRoot)
-      .flatMap(buildRootDir =>
-        Seq("build.sc", "build.mill", "build.mill.scala")
-          .map(buildRootDir / _)
-          .filterA(f => fileAlg.isRegularFile(f))
-          .map(_.nonEmpty)
-      )
+    workspaceAlg.buildRootDir(buildRoot).flatMap(findBuildFile).map(_.nonEmpty)
+
+  private def findBuildFile(buildRootDir: File): F[Option[File]] =
+    List("build.sc", "build.mill", "build.mill.scala")
+      .map(buildRootDir / _)
+      .findM(fileAlg.isRegularFile)
 
   private def runMill(buildRootDir: File, millBuildVersion: Option[Version]): F[List[String]] =
     millBuildVersion match {
@@ -103,7 +101,8 @@ final class MillAlg[F[_]](defaultResolver: Resolver)(implicit
       buildRootDir: File
   ): F[Seq[Scope[List[Dependency]]]] =
     for {
-      buildContent <- fileAlg.readFile(buildRootDir / "build.sc")
+      buildFile <- findBuildFile(buildRootDir)
+      buildContent <- buildFile.flatTraverse(fileAlg.readFile)
       deps = buildContent.toList.map(content =>
         Scope(parser.parseMillPluginDeps(content, millVersion), List(defaultResolver))
       )

modules/core/src/test/scala/org/scalasteward/core/buildtool/mill/MillAlgTest.scala

@@ -13,16 +13,16 @@ class MillAlgTest extends FunSuite {
   test("getDependencies, version < 0.11") {
     val repo = Repo("lihaoyi", "fastparse")
     val buildRoot = BuildRoot(repo, ".")
-    val repoDir = workspaceAlg.repoDir(repo).unsafeRunSync()
-    val predef = s"$repoDir/scala-steward.sc"
-    val millCmd = Cmd.execSandboxed(repoDir, "mill", "-i", "-p", predef, "show", extractDeps)
+    val buildRootDir = workspaceAlg.buildRootDir(buildRoot).unsafeRunSync()
+    val predef = s"$buildRootDir/scala-steward.sc"
+    val millCmd = Cmd.execSandboxed(buildRootDir, "mill", "-i", "-p", predef, "show", extractDeps)
     val initial =
       MockState.empty.copy(commandOutputs = Map(millCmd -> Right(List("""{"modules":[]}"""))))
     val state = millAlg.getDependencies(buildRoot).runS(initial).unsafeRunSync()
     val expected = initial.copy(
       trace = Vector(
-        Cmd("read", s"$repoDir/.mill-version"),
-        Cmd("read", s"$repoDir/.config/mill-version"),
+        Cmd("read", s"$buildRootDir/.mill-version"),
+        Cmd("read", s"$buildRootDir/.config/mill-version"),
         Cmd("write", predef),
         millCmd,
         Cmd("rm", "-rf", predef)
@@ -34,10 +34,9 @@ class MillAlgTest extends FunSuite {
   test("getDependencies, 0.11 <= version < 0.12") {
     val repo = Repo("lihaoyi", "fastparse")
     val buildRoot = BuildRoot(repo, ".")
-    val repoDir = workspaceAlg.repoDir(repo).unsafeRunSync()
     val buildRootDir = workspaceAlg.buildRootDir(buildRoot).unsafeRunSync()
     val millCmd = Cmd.execSandboxed(
-      repoDir,
+      buildRootDir,
       "mill",
       "--no-server",
       "--disable-ticker",
@@ -46,19 +45,17 @@ class MillAlgTest extends FunSuite {
       "show",
       extractDeps
     )
-    val initial =
-      MockState.empty
-        .copy(
-          commandOutputs = Map(millCmd -> Right(List("""{"modules":[]}""")))
-        )
-        .addFiles(buildRootDir / ".mill-version" -> "0.11.0")
-        .unsafeRunSync()
+    val initial = MockState.empty
+      .copy(commandOutputs = Map(millCmd -> Right(List("""{"modules":[]}"""))))
+      .addFiles(buildRootDir / ".mill-version" -> "0.11.0", buildRootDir / "build.sc" -> "")
+      .unsafeRunSync()
     val state = millAlg.getDependencies(buildRoot).runS(initial).unsafeRunSync()
     val expected = initial.copy(
       trace = Vector(
-        Cmd("read", s"$repoDir/.mill-version"),
+        Cmd("read", s"$buildRootDir/.mill-version"),
         millCmd,
-        Cmd("read", s"$repoDir/build.sc")
+        Cmd("test", "-f", s"$buildRootDir/build.sc"),
+        Cmd("read", s"$buildRootDir/build.sc")
       )
     )
     assertEquals(state, expected)
@@ -87,8 +84,8 @@ class MillAlgTest extends FunSuite {
     val expected = initial.copy(
       trace = Vector(
         Cmd("read", s"$buildRootDir/.mill-version"),
-        Cmd("read", s"$buildRootDir/.config/mill-version"),
         millCmd,
+        Cmd("test", "-f", s"$buildRootDir/build.sc"),
         Cmd("read", s"$buildRootDir/build.sc")
       )
     )