8026857: AnnoConstruct.getAnnotationsByType does not search supertype for inherited annotations if @SomeContainer({}) is present

An empty container should not stop javac from looking at supertypes for inherited repeating annotations

Reviewed-by: jjg

langtools/src/share/classes/com/sun/tools/javac/code/AnnoConstruct.java

@@ -117,17 +117,13 @@ public abstract class AnnoConstruct implements AnnotatedConstruct {
                 annoType.isAnnotationPresent(Inherited.class))
             return getInheritedAnnotations(annoType);
 
-        // Pack them in an array
-        Attribute[] contained0 = null;
-        if (container != null)
-            contained0 = unpackAttributes(container);
-        ListBuffer<Attribute.Compound> compounds = new ListBuffer<>();
-        if (contained0 != null) {
-            for (Attribute a : contained0)
-                if (a instanceof Attribute.Compound)
-                    compounds = compounds.append((Attribute.Compound)a);
-        }
-        Attribute.Compound[] contained = compounds.toArray(new Attribute.Compound[compounds.size()]);
+        Attribute.Compound[] contained = unpackContained(container);
+
+        // In case of an empty legacy container we might need to look for
+        // inherited annos as well
+        if (direct == null && contained.length == 0 &&
+                annoType.isAnnotationPresent(Inherited.class))
+            return getInheritedAnnotations(annoType);
 
         int size = (direct == null ? 0 : 1) + contained.length;
         @SuppressWarnings("unchecked") // annoType is the Class for A
@@ -159,6 +155,19 @@ public abstract class AnnoConstruct implements AnnotatedConstruct {
         return arr;
     }
 
+    private Attribute.Compound[] unpackContained(Attribute.Compound container) {
+        // Pack them in an array
+        Attribute[] contained0 = null;
+        if (container != null)
+            contained0 = unpackAttributes(container);
+        ListBuffer<Attribute.Compound> compounds = new ListBuffer<>();
+        if (contained0 != null) {
+            for (Attribute a : contained0)
+                if (a instanceof Attribute.Compound)
+                    compounds = compounds.append((Attribute.Compound)a);
+        }
+        return compounds.toArray(new Attribute.Compound[compounds.size()]);
+    }
 
     // This method is part of the javax.lang.model API, do not use this in javac code.
     public <A extends Annotation> A getAnnotation(Class<A> annoType) {

langtools/test/tools/javac/processing/model/element/TestEmptyContainer.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2013, 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
+ * @bug 8026857
+ * @summary Test that an empty container does not stop us from looking at
+ *          supertypes for inherited repeated annotations.
+ * @library /tools/javac/lib
+ * @build   JavacTestingAbstractProcessor TestEmptyContainer
+ * @compile -processor TestEmptyContainer -proc:only TestEmptyContainer.java
+ */
+
+import com.sun.tools.javac.util.Assert;
+
+import java.lang.annotation.*;
+import java.util.Arrays;
+import java.util.Set;
+import javax.annotation.processing.*;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.TypeElement;
+
+import static javax.lang.model.util.ElementFilter.*;
+
+@TestEmptyContainer.Foo(1)
+public class TestEmptyContainer extends JavacTestingAbstractProcessor {
+    public boolean process(Set<? extends TypeElement> annotations,
+                           RoundEnvironment roundEnv) {
+        if (!roundEnv.processingOver()) {
+            boolean hasRun = false;
+            for (Element element : roundEnv.getRootElements())
+                for (TypeElement te : typesIn(element.getEnclosedElements()))
+                    if (te.getQualifiedName().contentEquals("TestEmptyContainer.T2")) {
+                        hasRun = true;
+                        Foo[] foos = te.getAnnotationsByType(Foo.class);
+                        System.out.println("  " + te);
+                        System.out.println("  " + Arrays.asList(foos));
+                        Assert.check(foos.length == 1, "Should find one @Foo");
+                        Assert.check(foos[0].value() == 1, "Should find @Foo(1)");
+                    }
+            if (!hasRun)
+                throw new RuntimeException("Annotation processor couldn't find class T2, test broken!");
+        }
+        return true;
+    }
+
+    // This empty container should not stop us from finding @Foo(1) on TestEmptyContainer above
+    @TestEmptyContainer.FooContainer({})
+    public static class T2 extends TestEmptyContainer {
+    }
+
+    @Repeatable(FooContainer.class)
+    @Inherited
+    public static @interface Foo {
+        int value();
+    }
+
+    @Inherited
+    public static @interface FooContainer {
+        Foo[] value();
+    }
+}