8012722: Single comma in array initializer should parse

Annotations of the form @Foo({,}) should parse

Reviewed-by: jjg

langtools/src/share/classes/com/sun/tools/javac/parser/JavacParser.java

@@ -2914,7 +2914,9 @@ public class JavacParser implements Parser {
             pos = token.pos;
             accept(LBRACE);
             ListBuffer<JCExpression> buf = new ListBuffer<JCExpression>();
-            if (token.kind != RBRACE) {
+            if (token.kind == COMMA) {
+                nextToken();
+            } else if (token.kind != RBRACE) {
                 buf.append(annotationValue());
                 while (token.kind == COMMA) {
                     nextToken();

langtools/test/tools/javac/parser/SingleCommaAnnotationValue.java

@@ -0,0 +1,39 @@
+/*
+ * 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 8012722
+ * @summary Single comma in array initializer should parse
+ * @compile SingleCommaAnnotationValue.java
+ */
+
+public class SingleCommaAnnotationValue {
+    @Foo({}) void a() { }
+    @Foo({,}) void b() { }
+    @Foo({0}) void c() { }
+    @Foo({0,}) void d() { }
+    @Foo({0,0}) void e() { }
+    @Foo({0,0,}) void f() { }
+}
+@interface Foo { int[] value(); }

langtools/test/tools/javac/parser/SingleCommaAnnotationValueFail.java

@@ -0,0 +1,36 @@
+/*
+ * 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 8012722
+ * @summary Single comma in array initializer should parse
+ * @compile/fail/ref=SingleCommaAnnotationValueFail.out -XDrawDiagnostics
+ * SingleCommaAnnotationValueFail.java
+ */
+
+public class SingleCommaAnnotationValueFail {
+    // Non-example
+    @Foo({,0}) void a() { }
+}
+@interface Foo { int[] value(); }

langtools/test/tools/javac/parser/SingleCommaAnnotationValueFail.out

@@ -0,0 +1,6 @@
+SingleCommaAnnotationValueFail.java:34:12: compiler.err.expected: '}'
+SingleCommaAnnotationValueFail.java:34:13: compiler.err.illegal.start.of.type
+SingleCommaAnnotationValueFail.java:34:14: compiler.err.expected: token.identifier
+SingleCommaAnnotationValueFail.java:34:15: compiler.err.expected: ';'
+SingleCommaAnnotationValueFail.java:34:21: compiler.err.invalid.meth.decl.ret.type.req
+5 errors