Warn on output multiply set

Author: som-snytt

compiler/src/dotty/tools/dotc/config/Settings.scala

@@ -146,10 +146,11 @@ object Settings:
             case arg :: rest =>
               val path = Directory(arg)
               val isJar = path.extension == "jar"
-              if (!isJar && !path.isDirectory) fail(s"'$arg' does not exist or is not a directory or .jar file", rest)
+              if !isJar && !path.isDirectory then fail(s"'$arg' does not exist or is not a directory or .jar file", rest)
               else
-                val output = if (isJar) JarArchive.create(path) else new PlainDirectory(path)
-                update(output, rest)
+                val output = if isJar then JarArchive.create(path) else PlainDirectory(path)
+                if changed && output != valueIn(sstate).asInstanceOf[AbstractFile] then update(output, rest).warn(s"Option $name was updated")
+                else update(output, rest)
             case _ => missingArg
         case IntTag if argRest.nonEmpty => setInt(argRest, args)
         case IntTag =>

compiler/test/dotty/tools/dotc/SettingsTests.scala

@@ -7,15 +7,18 @@ import reporting.StoreReporter
 import vulpix.TestConfiguration
 
 import core.Contexts.{Context, ContextBase}
-import dotty.tools.dotc.config.Settings._
+import dotty.tools.Useables.given
+import dotty.tools.dotc.config.Settings.*
 import dotty.tools.vulpix.TestConfiguration.mkClasspath
 
-import java.nio.file._
+import java.nio.file.*, Files.*
 
 import org.junit.Test
 import org.junit.Assert.{assertEquals, assertFalse, assertTrue}
 
-class SettingsTests {
+import scala.util.Using
+
+class SettingsTests:
 
   @Test def missingOutputDir: Unit =
     val options = Array("-d", "not_here")
@@ -227,10 +230,25 @@ class SettingsTests {
     assertFalse("Multiple conflicting options is a warning", summary.warnings.isEmpty)
     assertTrue(summary.warnings.forall(_.contains("updated")))
 
+  @Test def `dir option also warns`: Unit =
+    import java.nio.file.Paths
+    import io.PlainFile, PlainFile.*
+    val abc: PlainFile = Paths.get("a", "b", "c").toPlainFile
+    object Settings extends SettingGroup:
+      val option = OutputSetting("-option", "out", "A file", Paths.get("a", "b", "c").toPlainFile)
+    Using.resource(createTempDirectory("i13887")) { dir =>
+      val target = createDirectory(dir.resolve("x"))
+      val mistake = createDirectory(dir.resolve("y"))
+      val args = List("-option", target.toString, "-option", mistake.toString)
+      val summary = Settings.processArguments(args, processAll = true)
+      assertTrue("Multiple options is not an error", summary.errors.isEmpty)
+      assertFalse("Multiple conflicting options is a warning", summary.warnings.isEmpty)
+      assertTrue(summary.warnings.forall(_.contains("updated")))
+    }
+
   // use the supplied summary for evaluating settings
   private def withProcessedArgs(summary: ArgsSummary)(f: SettingsState ?=> Unit) = f(using summary.sstate)
 
   // evaluate a setting using only a SettingsState (instead of a full-blown Context)
   extension [T](setting: Setting[T])
     private def value(using ss: SettingsState): T = setting.valueIn(ss)
-}

compiler/test/dotty/tools/utils.scala

@@ -11,7 +11,7 @@ import java.nio.file.{Files, Path => JPath}
 import scala.io.Source
 import scala.jdk.StreamConverters._
 import scala.reflect.ClassTag
-import scala.util.Using.resource
+import scala.util.Using.{Releasable, resource}
 import scala.util.chaining.given
 import scala.util.control.{ControlThrowable, NonFatal}
 
@@ -35,6 +35,24 @@ def withFile[T](file: File)(action: Source => T): T = resource(Source.fromFile(f
 def readLines(f: File): List[String]                = withFile(f)(_.getLines.toList)
 def readFile(f: File): String                       = withFile(f)(_.mkString)
 
+// Make common types useable with Using.
+object Useables:
+  import java.io.IOException
+  import java.nio.file.{FileVisitResult, SimpleFileVisitor}, FileVisitResult.{CONTINUE => Continue}
+  import java.nio.file.attribute.*
+  import scala.util.Properties
+
+  // delete the result of createTempDirectory
+  given Releasable[JPath] with
+    override def release(released: JPath) = if (!Properties.isWin) remove(released)
+  private def remove(path: JPath): Unit = if Files.isDirectory(path) then removeRecursively(path) else Files.delete(path)
+  private def removeRecursively(path: JPath): Unit = Files.walkFileTree(path, ZappingFileVisitor())
+  private class ZappingFileVisitor extends SimpleFileVisitor[JPath]:
+    private def zap(path: JPath) = { Files.delete(path) ; Continue }
+    override def postVisitDirectory(path: JPath, e: IOException): FileVisitResult = if e != null then throw e else zap(path)
+    override def visitFile(path: JPath, attrs: BasicFileAttributes): FileVisitResult = zap(path)
+end Useables
+
 private object Unthrown extends ControlThrowable
 
 def assertThrows[T <: Throwable: ClassTag](p: T => Boolean)(body: => Any): Unit =
@@ -68,4 +86,4 @@ def toolArgsParse(lines: List[String]): List[String] = {
     // but avoid picking up comments like "% scalac ./a.scala" and "$ scalac a.scala"
   }.map(stripped).headOption
   args.map(dotc.config.CommandLineParser.tokenize).getOrElse(Nil)
-}
+}