error when reading class file with unknown newer jdk version

Author: bishabosha

compiler/src/dotty/tools/dotc/core/classfile/ClassfileConstants.scala

@@ -11,6 +11,7 @@ object ClassfileConstants {
   inline val JAVA_MINOR_VERSION = 3
 
   inline val JAVA8_MAJOR_VERSION = 52
+  inline val JAVA_LATEST_MAJOR_VERSION = 65
 
   /** (see http://java.sun.com/docs/books/jvms/second_edition/jvms-clarify.html)
    *

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -55,6 +55,22 @@ object ClassfileParser {
     }
   }
 
+  private[classfile] def parseHeader(classfile: AbstractFile)(using in: DataReader): Unit = {
+    val magic = in.nextInt
+    if (magic != JAVA_MAGIC)
+      throw new IOException(s"class file '${classfile}' has wrong magic number 0x${toHexString(magic)}, should be 0x${toHexString(JAVA_MAGIC)}")
+    val minorVersion = in.nextChar.toInt
+    val majorVersion = in.nextChar.toInt
+    if ((majorVersion < JAVA_MAJOR_VERSION) ||
+        ((majorVersion == JAVA_MAJOR_VERSION) &&
+         (minorVersion < JAVA_MINOR_VERSION)))
+      throw new IOException(
+        s"class file '${classfile}' has unknown version $majorVersion.$minorVersion, should be at least $JAVA_MAJOR_VERSION.$JAVA_MINOR_VERSION")
+    if majorVersion > JAVA_LATEST_MAJOR_VERSION then
+      throw new IOException(
+        s"class file '${classfile}' has unknown version $majorVersion.$minorVersion, and was compiled by a newer JDK than supported by this Scala version, please update to a newer Scala version.")
+  }
+
   abstract class AbstractConstantPool(using in: DataReader) {
     protected val len = in.nextChar
     protected val starts = new Array[Int](len)
@@ -257,7 +273,7 @@ class ClassfileParser(
   def run()(using Context): Option[Embedded] = try ctx.base.reusableDataReader.withInstance { reader =>
     implicit val reader2 = reader.reset(classfile)
     report.debuglog("[class] >> " + classRoot.fullName)
-    parseHeader()
+    parseHeader(classfile)
     this.pool = new ConstantPool
     val res = parseClass()
     this.pool =  null
@@ -271,19 +287,6 @@ class ClassfileParser(
            |${Option(e.getMessage).getOrElse("")}""")
   }
 
-  private def parseHeader()(using in: DataReader): Unit = {
-    val magic = in.nextInt
-    if (magic != JAVA_MAGIC)
-      throw new IOException(s"class file '${classfile}' has wrong magic number 0x${toHexString(magic)}, should be 0x${toHexString(JAVA_MAGIC)}")
-    val minorVersion = in.nextChar.toInt
-    val majorVersion = in.nextChar.toInt
-    if ((majorVersion < JAVA_MAJOR_VERSION) ||
-        ((majorVersion == JAVA_MAJOR_VERSION) &&
-         (minorVersion < JAVA_MINOR_VERSION)))
-      throw new IOException(
-        s"class file '${classfile}' has unknown version $majorVersion.$minorVersion, should be at least $JAVA_MAJOR_VERSION.$JAVA_MINOR_VERSION")
-  }
-
   /** Return the class symbol of the given name. */
   def classNameToSymbol(name: Name)(using Context): Symbol =
     val nameStr = name.toString

compiler/src/dotty/tools/dotc/core/classfile/ClassfileTastyUUIDParser.scala

@@ -25,7 +25,7 @@ class ClassfileTastyUUIDParser(classfile: AbstractFile)(ictx: Context) {
 
   def checkTastyUUID(tastyUUID: UUID)(using Context): Unit = try ctx.base.reusableDataReader.withInstance { reader =>
     implicit val reader2 = reader.reset(classfile)
-    parseHeader()
+    ClassfileParser.parseHeader(classfile)
     this.pool = new ConstantPool
     checkTastyAttr(tastyUUID)
     this.pool =  null
@@ -38,19 +38,6 @@ class ClassfileTastyUUIDParser(classfile: AbstractFile)(ictx: Context) {
            |${Option(e.getMessage).getOrElse("")}""")
   }
 
-  private def parseHeader()(using in: DataReader): Unit = {
-    val magic = in.nextInt
-    if (magic != JAVA_MAGIC)
-      throw new IOException(s"class file '${classfile}' has wrong magic number 0x${toHexString(magic)}, should be 0x${toHexString(JAVA_MAGIC)}")
-    val minorVersion = in.nextChar.toInt
-    val majorVersion = in.nextChar.toInt
-    if ((majorVersion < JAVA_MAJOR_VERSION) ||
-        ((majorVersion == JAVA_MAJOR_VERSION) &&
-         (minorVersion < JAVA_MINOR_VERSION)))
-      throw new IOException(
-        s"class file '${classfile}' has unknown version $majorVersion.$minorVersion, should be at least $JAVA_MAJOR_VERSION.$JAVA_MINOR_VERSION")
-  }
-
   private def checkTastyAttr(tastyUUID: UUID)(using ctx: Context, in: DataReader): Unit = {
     in.nextChar // jflags
     in.nextChar // nameIdx