Only allow jar and tasty as input for -from-tasty

This ensures that we don't accidentally load other versions of the classes that are on the current classpath.

Author: nicolasstucki

compiler/src/dotty/tools/dotc/Driver.scala

@@ -86,26 +86,28 @@ class Driver {
   protected def fromTastySetup(fileNames0: List[String], ctx0: Context): (List[String], Context) =
     given Context = ctx0
     if (ctx0.settings.fromTasty.value) {
+      val fromTastyFilter = ctx0.settings.YfromTastyFilter.value
+      val filter =
+        if fromTastyFilter.isEmpty then ".*".r
+        else fromTastyFilter.r
       // Resolve classpath and class names of tasty files
-      val (classPaths, classNames) = fileNames0.flatMap { name =>
-        val path = Paths.get(name)
-        if (name.endsWith(".jar"))
-          new dotty.tools.io.Jar(File(name)).toList.collect {
-            case e if e.getName.endsWith(".tasty") =>
-              (name, e.getName.stripSuffix(".tasty").replace("/", "."))
+      val (classPaths, classNames) = fileNames0.flatMap { fileName =>
+        val path = Paths.get(fileName)
+        if (fileName.endsWith(".jar"))
+          new dotty.tools.io.Jar(File(fileName)).toList.collect {
+            case e if e.getName.endsWith(".tasty") && filter.matches(e.getName) =>
+              (fileName, e.getName.stripSuffix(".tasty").replace("/", "."))
           }
-        else if (!name.endsWith(".tasty"))
-          ("", name) :: Nil
-        else if (Files.exists(path))
+        else if Files.exists(path) then
           TastyFileUtil.getClassName(path) match {
             case Some(res) => res:: Nil
             case _ =>
-              report.error(s"Could not load classname from $name.")
-              ("", name) :: Nil
+              report.error(s"Could not load classname from: $fileName")
+              Nil
           }
         else {
-          report.error(s"File $name does not exist.")
-          ("", name) :: Nil
+          report.error(s"File not found: $fileName")
+          Nil
         }
       }.unzip
       val ctx1 = ctx0.fresh

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

@@ -45,7 +45,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val language: Setting[List[String]] = MultiStringSetting("-language", "feature", "Enable one or more language features.") withAbbreviation "--language"
   val rewrite: Setting[Option[Rewrites]] = OptionSetting[Rewrites]("-rewrite", "When used in conjunction with a `...-migration` source version, rewrites sources to migrate to new version.") withAbbreviation "--rewrite"
   val silentWarnings: Setting[Boolean] = BooleanSetting("-nowarn", "Silence all warnings.") withAbbreviation "--no-warnings"
-  val fromTasty: Setting[Boolean] = BooleanSetting("-from-tasty", "Compile classes from tasty in classpath. The arguments are used as class names.") withAbbreviation "--from-tasty"
+  val fromTasty: Setting[Boolean] = BooleanSetting("-from-tasty", "Compile classes from tasty files. The arguments are .tasty or .jar files.") withAbbreviation "--from-tasty"
 
   val newSyntax: Setting[Boolean] = BooleanSetting("-new-syntax", "Require `then` and `do` in control expressions.")
   val oldSyntax: Setting[Boolean] = BooleanSetting("-old-syntax", "Require `(...)` around conditions.")
@@ -158,6 +158,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val YretainTrees: Setting[Boolean] = BooleanSetting("-Yretain-trees", "Retain trees for top-level classes, accessible from ClassSymbol#tree")
   val Ysemanticdb: Setting[Boolean] = BooleanSetting("-Ysemanticdb", "Store information in SemanticDB.")
   val YshowTreeIds: Setting[Boolean] = BooleanSetting("-Yshow-tree-ids", "Uniquely tag all tree nodes in debugging output.")
+  val YfromTastyFilter: Setting[String] = StringSetting("-Yfrom-tasty-filter", "file", "Filter tasty files in jar files when using -from-tasty", "")
 
   val YprofileEnabled: Setting[Boolean] = BooleanSetting("-Yprofile-enabled", "Enable profiling.")
   val YprofileDestination: Setting[String] = StringSetting("-Yprofile-destination", "file", "Where to send profiling output - specify a file, default is to the console.", "")