Avoid overeager completion of annotations in classfile parser

Author: griggt

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -961,13 +961,9 @@ class Definitions {
   @tu lazy val NativeAnnot: ClassSymbol = requiredClass("scala.native")
   @tu lazy val RepeatedAnnot: ClassSymbol = requiredClass("scala.annotation.internal.Repeated")
   @tu lazy val SourceFileAnnot: ClassSymbol = requiredClass("scala.annotation.internal.SourceFile")
-  @tu lazy val ScalaSignatureAnnot: ClassSymbol = requiredClass("scala.reflect.ScalaSignature")
-  @tu lazy val ScalaLongSignatureAnnot: ClassSymbol = requiredClass("scala.reflect.ScalaLongSignature")
   @tu lazy val ScalaStrictFPAnnot: ClassSymbol = requiredClass("scala.annotation.strictfp")
   @tu lazy val ScalaStaticAnnot: ClassSymbol = requiredClass("scala.annotation.static")
   @tu lazy val SerialVersionUIDAnnot: ClassSymbol = requiredClass("scala.SerialVersionUID")
-  @tu lazy val TASTYSignatureAnnot: ClassSymbol = requiredClass("scala.annotation.internal.TASTYSignature")
-  @tu lazy val TASTYLongSignatureAnnot: ClassSymbol = requiredClass("scala.annotation.internal.TASTYLongSignature")
   @tu lazy val TailrecAnnot: ClassSymbol = requiredClass("scala.annotation.tailrec")
   @tu lazy val ThreadUnsafeAnnot: ClassSymbol = requiredClass("scala.annotation.threadUnsafe")
   @tu lazy val ConstructorOnlyAnnot: ClassSymbol = requiredClass("scala.annotation.constructorOnly")

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

@@ -51,6 +51,12 @@ object ClassfileParser {
         mapOver(tp)
     }
   }
+
+  private inline def sigOfClassName(n: String) = s"L$n;"
+  val ScalaSignatureAnnot: String = sigOfClassName("scala.reflect.ScalaSignature")
+  val ScalaLongSignatureAnnot: String = sigOfClassName("scala.reflect.ScalaLongSignature")
+  val TASTYSignatureAnnot: String = sigOfClassName("scala.annotation.internal.TASTYSignature")
+  val TASTYLongSignatureAnnot: String = sigOfClassName("scala.annotation.internal.TASTYLongSignature")
 }
 
 class ClassfileParser(
@@ -1033,19 +1039,19 @@ class ClassfileParser(
         val nAnnots = in.nextChar
         var i = 0
         while (i < nAnnots) {
-          val attrClass = pool.getType(in.nextChar).typeSymbol
+          val attrSig = pool.getExternalName(in.nextChar).value
           val nArgs = in.nextChar
           var j = 0
           while (j < nArgs) {
             val argName = pool.getName(in.nextChar)
             if (argName.name == nme.bytes) {
-              if (attrClass == defn.ScalaSignatureAnnot)
+              if attrSig == ScalaSignatureAnnot then
                 return unpickleScala(parseScalaSigBytes)
-              else if (attrClass == defn.ScalaLongSignatureAnnot)
+              else if attrSig == ScalaLongSignatureAnnot then
                 return unpickleScala(parseScalaLongSigBytes)
-              else if (attrClass == defn.TASTYSignatureAnnot)
+              else if attrSig == TASTYSignatureAnnot then
                 return unpickleTASTY(parseScalaSigBytes)
-              else if (attrClass == defn.TASTYLongSignatureAnnot)
+              else if attrSig == TASTYLongSignatureAnnot then
                 return unpickleTASTY(parseScalaLongSigBytes)
             }
             parseAnnotArg(skip = true)

tests/pos/i15166/InterfaceAudience_JAVA_ONLY_1.java

@@ -0,0 +1,8 @@
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@InterfaceStability_JAVA_ONLY_1.Evolving(bytes="no")
+public class InterfaceAudience_JAVA_ONLY_1 {
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface Public { String bytes(); }
+}

tests/pos/i15166/InterfaceStability_JAVA_ONLY_1.java

@@ -0,0 +1,8 @@
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@InterfaceAudience_JAVA_ONLY_1.Public(bytes="yes")
+public class InterfaceStability_JAVA_ONLY_1 {
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface Evolving { String bytes(); }
+}

tests/pos/i15166/Test_2.scala

@@ -0,0 +1,4 @@
+// scalac: -Xfatal-warnings
+object Test {
+  val x: InterfaceAudience_JAVA_ONLY_1.Public = ???
+}