Report error if scala script not exists

modules/build/src/main/scala/scala/build/preprocessing/PreprocessingUtil.scala

@@ -0,0 +1,14 @@
+package scala.build.preprocessing
+
+import java.nio.charset.StandardCharsets
+
+import scala.build.errors.{BuildException, FileNotFoundException}
+
+object PreprocessingUtil {
+
+  private def defaultCharSet = StandardCharsets.UTF_8
+
+  def maybeRead(f: os.Path): Either[BuildException, String] =
+    if (os.isFile(f)) Right(os.read(f, defaultCharSet))
+    else Left(new FileNotFoundException(f))
+}

modules/build/src/main/scala/scala/build/preprocessing/ScalaPreprocessor.scala

@@ -9,12 +9,7 @@ import java.nio.charset.StandardCharsets
 
 import scala.build.EitherCps.{either, value}
 import scala.build.Ops._
-import scala.build.errors.{
-  BuildException,
-  CompositeBuildException,
-  DependencyFormatError,
-  FileNotFoundException
-}
+import scala.build.errors.{BuildException, CompositeBuildException, DependencyFormatError}
 import scala.build.internal.{AmmUtil, Util}
 import scala.build.options.{BuildOptions, BuildRequirements, ClassPathOptions}
 import scala.build.preprocessing.directives._
@@ -72,12 +67,6 @@ case object ScalaPreprocessor extends Preprocessor {
     RequireScopeDirectiveHandler
   )
 
-  private def defaultCharSet = StandardCharsets.UTF_8
-
-  private def maybeRead(f: os.Path): Either[BuildException, String] =
-    if (os.isFile(f)) Right(os.read(f, defaultCharSet))
-    else Left(new FileNotFoundException(f))
-
   def preprocess(
     input: Inputs.SingleElement,
     logger: Logger
@@ -89,7 +78,7 @@ case object ScalaPreprocessor extends Preprocessor {
           (pkg :+ wrapper).map(_.raw).mkString(".")
         }
         val res = either {
-          val content   = value(maybeRead(f.path))
+          val content   = value(PreprocessingUtil.maybeRead(f.path))
           val scopePath = ScopePath.fromPath(f.path)
           val source = value(process(content, Right(f.path), scopePath / os.up, logger)) match {
             case None =>

modules/build/src/main/scala/scala/build/preprocessing/ScriptPreprocessor.scala

@@ -16,9 +16,8 @@ final case class ScriptPreprocessor(codeWrapper: CodeWrapper) extends Preprocess
   ): Option[Either[BuildException, Seq[PreprocessedSource]]] =
     input match {
       case script: Inputs.Script =>
-        val content = os.read(script.path)
-
         val res = either {
+          val content = value(PreprocessingUtil.maybeRead(script.path))
           val preprocessed = value {
             ScriptPreprocessor.preprocess(
               Right(script.path),

modules/build/src/test/scala/scala/build/tests/PreprocessingTests.scala

@@ -0,0 +1,34 @@
+package scala.build.tests
+
+import scala.build.Inputs
+import scala.build.preprocessing.{ScalaPreprocessor, ScriptPreprocessor}
+import com.eed3si9n.expecty.Expecty.{expect, assert => expect}
+
+import scala.build.internal.CustomCodeWrapper
+
+class PreprocessingTests extends munit.FunSuite {
+
+  test("Report error if scala file not exists") {
+    val logger    = TestLogger()
+    val scalaFile = Inputs.ScalaFile(os.temp.dir(), os.SubPath("NotExists.scala"))
+
+    val res             = ScalaPreprocessor.preprocess(scalaFile, logger)
+    val expectedMessage = s"File not found: ${scalaFile.path}"
+
+    assert(res.nonEmpty)
+    assert(res.get.isLeft)
+    expect(res.get.left.get.message == expectedMessage)
+  }
+
+  test("Report error if scala script not exists") {
+    val logger      = TestLogger()
+    val scalaScript = Inputs.Script(os.temp.dir(), os.SubPath("NotExists.sc"))
+
+    val res             = ScriptPreprocessor(CustomCodeWrapper).preprocess(scalaScript, logger)
+    val expectedMessage = s"File not found: ${scalaScript.path}"
+
+    assert(res.nonEmpty)
+    assert(res.get.isLeft)
+    expect(res.get.left.get.message == expectedMessage)
+  }
+}