From 086095399e73ef62652cc918959b9cdbedbd4ae8 Mon Sep 17 00:00:00 2001
From: "Jason T. Greene" <jason.greene@redhat.com>
Date: Wed, 11 Nov 2020 14:48:13 -0600
Subject: [PATCH] Ignore bogus type annotation entries - Fixes #93

---
 src/main/java/org/jboss/jandex/Indexer.java | 29 ++++++++++++++-------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/main/java/org/jboss/jandex/Indexer.java b/src/main/java/org/jboss/jandex/Indexer.java
index 95438432..e46461dc 100644
--- a/src/main/java/org/jboss/jandex/Indexer.java
+++ b/src/main/java/org/jboss/jandex/Indexer.java
@@ -534,10 +534,12 @@ private TypeAnnotationState processTypeAnnotation(DataInputStream data, Annotati
             }
             case 0x10: // CLASS_EXTENDS
             {
-                if (!(target instanceof ClassInfo)) {
-                    throw new IllegalStateException("Class extends type annotation appeared on a non class target");
+                int position = data.readUnsignedShort();
+
+                // Skip invalid usage (observed bad bytecode on method attributes)
+                if (target instanceof ClassInfo) {
+                    typeTarget = new ClassExtendsTypeTarget((ClassInfo)target, position);
                 }
-                typeTarget = new ClassExtendsTypeTarget((ClassInfo)target, data.readUnsignedShort());
                 break;
             }
             case 0x11: // CLASS_TYPE_PARAMETER_BOUND
@@ -553,18 +555,18 @@ private TypeAnnotationState processTypeAnnotation(DataInputStream data, Annotati
                 break;
             case 0x16: // METHOD_FORMAL_PARAMETER
             {
-                if (!(target instanceof MethodInfo)) {
-                    throw new IllegalStateException("Method parameter type annotation appeared on a non-method target");
+                int position = data.readUnsignedByte();
+                if (target instanceof MethodInfo) {
+                    typeTarget = new MethodParameterTypeTarget((MethodInfo)target, position);
                 }
-                typeTarget = new MethodParameterTypeTarget((MethodInfo)target, data.readUnsignedByte());
                 break;
             }
             case 0x17: // THROWS
             {
-                if (!(target instanceof MethodInfo)) {
-                    throw new IllegalStateException("Throws type annotation appeared on a non-method target");
+                int position = data.readUnsignedShort();
+                if (target instanceof MethodInfo) {
+                    typeTarget = new ThrowsTypeTarget((MethodInfo) target, position);
                 }
-                typeTarget = new ThrowsTypeTarget((MethodInfo) target, data.readUnsignedShort());
                 break;
             }
             // Skip code attribute values, which shouldn't be present
@@ -595,6 +597,10 @@ private TypeAnnotationState processTypeAnnotation(DataInputStream data, Annotati
         }
 
         if (typeTarget == null) {
+            skipTargetPath(data);
+            // eat
+            // TODO - introduce an allocation free annotation skip
+            processAnnotation(data, null);
             return null;
         }
 
@@ -1055,6 +1061,11 @@ private ArrayList<PathElement> processTargetPath(DataInputStream data, BooleanHo
         return elements;
     }
 
+    private void skipTargetPath(DataInputStream data) throws IOException {
+           int numElements = data.readUnsignedByte();
+           skipFully(data, numElements * 2);
+    }
+
     private void processExceptions(DataInputStream data, MethodInfo target) throws IOException {
         int numExceptions = data.readUnsignedShort();