8337302: Undefined type variable results in null

Reviewed-by: liach

Author: raphw

src/java.base/share/classes/java/lang/TypeNotPresentException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,9 +28,9 @@
 /**
  * Thrown when an application tries to access a type using a string
  * representing the type's name, but no definition for the type with
- * the specified name can be found.   This exception differs from
- * {@link ClassNotFoundException} in that {@code ClassNotFoundException} is a
- * checked exception, whereas this exception is unchecked.
+ * the specified name can be found. This exception differs from
+ * {@link ClassNotFoundException} in that {@code ClassNotFoundException}
+ * is a checked exception, whereas this exception is unchecked.
  *
  * <p>Note that this exception may be used when undefined type variables
  * are accessed as well as when types (e.g., classes, interfaces or
@@ -48,15 +48,15 @@ public class TypeNotPresentException extends RuntimeException {
     private static final long serialVersionUID = -5101214195716534496L;
 
     /**
-     * The type name.
+     * The type name or the name of a type variable.
      */
     private String typeName;
 
     /**
-     * Constructs a {@code TypeNotPresentException} for the named type
-     * with the specified cause.
+     * Constructs a {@code TypeNotPresentException} for the named type or
+     * type variable with the specified cause.
      *
-     * @param typeName the fully qualified name of the unavailable type
+     * @param typeName the fully qualified name of the unavailable type or type variable
      * @param cause the exception that was thrown when the system attempted to
      *    load the named type, or {@code null} if unavailable or inapplicable
      */
@@ -66,9 +66,9 @@ public TypeNotPresentException(String typeName, Throwable cause) {
     }
 
     /**
-     * Returns the fully qualified name of the unavailable type.
+     * Returns the fully qualified name of the unavailable type or type variable name.
      *
-     * @return the fully qualified name of the unavailable type
+     * @return the fully qualified name of the unavailable type or type variable name
      */
     public String typeName() { return typeName;}
 }

src/java.base/share/classes/sun/reflect/generics/factory/CoreReflectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -106,7 +106,11 @@ public ParameterizedType makeParameterizedType(Type declaration,
     }
 
     public TypeVariable<?> findTypeVariable(String name){
-        return getScope().lookup(name);
+        TypeVariable<?> variable = getScope().lookup(name);
+        if (variable == null) {
+            throw new TypeNotPresentException(name, null);
+        }
+        return variable;
     }
 
     public Type makeNamedType(String name){

test/jdk/java/lang/reflect/Generics/TestMissingTypeVariable.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @library /test/lib
+ * @bug 8337302
+ * @enablePreview
+ * @summary Tests that an exception is thrown if a type variable is not declared
+ */
+
+import jdk.test.lib.ByteCodeLoader;
+
+import java.lang.classfile.ClassFile;
+import java.lang.classfile.Signature;
+import java.lang.classfile.attribute.SignatureAttribute;
+import java.lang.constant.ClassDesc;
+import java.lang.reflect.AccessFlag;
+import java.lang.reflect.Type;
+
+public class TestMissingTypeVariable {
+
+    public static void main(String[] args) throws Exception {
+        ClassFile cf = ClassFile.of();
+        byte[] bytes = cf.build(
+                ClassDesc.of("sample.MissingVariable"),
+                classBuilder -> {
+                    classBuilder.withSuperclass(ClassDesc.of("java.lang.Object"));
+                    classBuilder.withFlags(AccessFlag.PUBLIC);
+                    classBuilder.withField("f",
+                            ClassDesc.of("java.lang.Object"),
+                            fieldBuilder -> fieldBuilder.withFlags(AccessFlag.PUBLIC).with(SignatureAttribute.of(Signature.parseFrom("TA;"))));
+                });
+        /*
+          package sample;
+          public class MissingVariable {
+            public A f; // undeclared type variable
+          }
+         */
+        Class<?> missing = ByteCodeLoader.load("sample.MissingVariable", bytes);
+        try {
+            Type type = missing.getField("f").getGenericType();
+            throw new IllegalStateException("Expected TypeNotPresentException but got: " + type);
+        } catch (TypeNotPresentException e) {
+            if (!"A".equals(e.typeName())) {
+                throw new IllegalStateException("Unexpected name: " + e.typeName());
+            }
+        }
+    }
+}