BuildTarget: Resolve exception when no parent modules available

This fixes a regression introduced in 62d654e.

src/main/scala/seed/cli/BuildTarget.scala

@@ -85,15 +85,16 @@ object BuildTarget {
         val modulePath = build(m).path
         val target     = build(m).module.target(t)
 
-        val moduleSourcePaths = parentModules((m, t)).flatMap { module =>
-          val targets = BuildConfig.allTargets(build, module)
-          targets
-            .flatMap {
-              case (m, t) => BuildConfig.platformModule(build(m).module, t)
-            }
-            .flatMap(_.sources)
-            .map(_.toAbsolutePath.toString)
-        }
+        val moduleSourcePaths =
+          parentModules.getOrElse((m, t), List()).flatMap { module =>
+            val targets = BuildConfig.allTargets(build, module)
+            targets
+              .flatMap {
+                case (m, t) => BuildConfig.platformModule(build(m).module, t)
+              }
+              .flatMap(_.sources)
+              .map(_.toAbsolutePath.toString)
+          }
 
         target.`class` match {
           case Some(c) =>

src/test/scala/seed/generation/BloopIntegrationSpec.scala

@@ -6,19 +6,17 @@ import bloop.config.Config.JsConfig
 import bloop.config.ConfigEncoderDecoders
 import minitest.TestSuite
 import org.apache.commons.io.FileUtils
-import seed.{Log, LogLevel, cli}
+import seed.{Log, cli}
 import seed.Cli.{Command, PackageConfig}
 import seed.cli.util.RTS
 import seed.config.BuildConfig
-import seed.generation.util.TestProcessHelper
+import seed.generation.util.{CustomTargetUtil, TestProcessHelper}
 import seed.generation.util.TestProcessHelper.ec
 import seed.model.Config
 
 import scala.concurrent.Future
 import seed.generation.util.BuildUtil.tempPath
 
-import scala.collection.mutable.ListBuffer
-
 object BloopIntegrationSpec extends TestSuite[Unit] {
   override def setupSuite(): Unit    = TestProcessHelper.semaphore.acquire()
   override def tearDownSuite(): Unit = TestProcessHelper.semaphore.release()
@@ -278,72 +276,44 @@ object BloopIntegrationSpec extends TestSuite[Unit] {
       }
   }
 
-  def buildCustomTarget(
+  def buildCustomTargetAndRun(
     name: String,
     expectFailure: Boolean = false
   ): Future[Either[List[String], List[String]]] = {
-    val path = Paths.get("test", name)
-
-    val config = BuildConfig.load(path, Log.urgent).get
+    val (config, lines, uio) = CustomTargetUtil.buildCustomTarget(name, "demo")
     import config._
-    val buildPath = tempPath.resolve(name)
-    Files.createDirectory(buildPath)
-    cli.Generate.ui(
-      Config(),
-      projectPath,
-      buildPath,
-      resolvers,
-      build,
-      Command.Bloop(packageConfig),
-      Log.urgent
-    )
-
-    val lines = ListBuffer[String]()
-
-    val result = seed.cli.Build.build(
-      path,
-      Some(buildPath),
-      List("demo"),
-      watch = false,
-      tmpfs = false,
-      progress = false,
-      new Log(lines += _, identity, LogLevel.Warn, false),
-      stdOut => lines ++= stdOut.split('\n'),
-      _ => ()
-    )
-
-    val uio = result.right.get
 
     if (expectFailure)
       RTS.unsafeRunToFuture(uio).failed.map { _ =>
         assert(lines.nonEmpty)
-        Left(lines.toList)
+        Left(lines)
       } else {
       RTS.unsafeRunSync(uio)
 
       val generatedFile = projectPath.resolve("demo").resolve("Generated.scala")
       assert(Files.exists(generatedFile))
 
+      val buildPath = tempPath.resolve(name)
       TestProcessHelper
         .runBloop(buildPath)("run", "demo")
         .map { x =>
           Files.delete(generatedFile)
-          assertEquals(lines.toList, List())
+          assertEquals(lines, List())
           Right(x.split("\n").toList)
         }
     }
   }
 
   testAsync("Build project with custom class target") { _ =>
-    buildCustomTarget("custom-class-target").map(
+    buildCustomTargetAndRun("custom-class-target").map(
       lines => assertEquals(lines.right.get.count(_ == "42"), 1)
     )
   }
 
   testAsync(
     "Build project with custom class target (shared by multiple modules)"
   ) { _ =>
-    buildCustomTarget("custom-class-target-shared").map(
+    buildCustomTargetAndRun("custom-class-target-shared").map(
       lines =>
         assertEquals(
           lines.right.get.map(_.split("test/").last),
@@ -356,7 +326,7 @@ object BloopIntegrationSpec extends TestSuite[Unit] {
   }
 
   testAsync("Build project with custom command target") { _ =>
-    buildCustomTarget("custom-command-target").map { lines =>
+    buildCustomTargetAndRun("custom-command-target").map { lines =>
       assertEquals(lines.right.get.count(_ == "42"), 1)
 
       val path = tempPath
@@ -377,12 +347,12 @@ object BloopIntegrationSpec extends TestSuite[Unit] {
   }
 
   testAsync("Build project with failing custom command target") { _ =>
-    buildCustomTarget("custom-command-target-fail", expectFailure = true)
+    buildCustomTargetAndRun("custom-command-target-fail", expectFailure = true)
       .map(_ => ())
   }
 
   testAsync("Build project with failing compilation") { _ =>
-    buildCustomTarget("compilation-failure", expectFailure = true).map(
+    buildCustomTargetAndRun("compilation-failure", expectFailure = true).map(
       log =>
         // Must indicate correct position
         assert(

src/test/scala/seed/generation/BuildTargetSpec.scala

@@ -0,0 +1,27 @@
+package seed.generation
+
+import java.nio.file.Files
+
+import minitest.TestSuite
+import seed.cli.util.RTS
+import seed.generation.util.{CustomTargetUtil, TestProcessHelper}
+import seed.generation.util.TestProcessHelper.ec
+
+object BuildTargetSpec extends TestSuite[Unit] {
+  override def setupSuite(): Unit    = TestProcessHelper.semaphore.acquire()
+  override def tearDownSuite(): Unit = TestProcessHelper.semaphore.release()
+
+  override def setup(): Unit             = ()
+  override def tearDown(env: Unit): Unit = ()
+
+  testAsync("Build custom target") { _ =>
+    val (config, _, uio) =
+      CustomTargetUtil.buildCustomTarget("custom-command-target", "utils")
+    import config._
+    RTS.unsafeRunToFuture(uio).map { _ =>
+      val generatedFile = projectPath.resolve("demo").resolve("Generated.scala")
+      assert(Files.exists(generatedFile))
+      Files.delete(generatedFile)
+    }
+  }
+}

src/test/scala/seed/generation/util/CustomTargetUtil.scala

@@ -0,0 +1,52 @@
+package seed.generation.util
+
+import java.nio.file.{Files, Paths}
+
+import seed.Cli.Command
+import seed.{Log, LogLevel, cli}
+import seed.config.BuildConfig
+import seed.generation.BloopIntegrationSpec.packageConfig
+import seed.generation.util.BuildUtil.tempPath
+import seed.model.Config
+
+import scala.collection.mutable.ListBuffer
+
+object CustomTargetUtil {
+  def buildCustomTarget(
+    name: String,
+    module: String
+  ): (BuildConfig.Result, List[String], zio.UIO[Unit]) = {
+    val path = Paths.get("test", name)
+
+    val config = BuildConfig.load(path, Log.urgent).get
+    import config._
+    val buildPath = tempPath.resolve(name)
+    Files.createDirectory(buildPath)
+    cli.Generate.ui(
+      Config(),
+      projectPath,
+      buildPath,
+      resolvers,
+      build,
+      Command.Bloop(packageConfig),
+      Log.urgent
+    )
+
+    val lines = ListBuffer[String]()
+
+    val result = seed.cli.Build.build(
+      path,
+      Some(buildPath),
+      List(module),
+      watch = false,
+      tmpfs = false,
+      progress = false,
+      new Log(lines += _, identity, LogLevel.Warn, false),
+      stdOut => lines ++= stdOut.split('\n'),
+      _ => ()
+    )
+
+    val uio = result.right.get
+    (config, lines.toList, uio)
+  }
+}