8340568: Incorrect escaping of single quotes when pretty-printing character literals

Reviewed-by: mcimadamore

Author: cushon

src/jdk.compiler/share/classes/com/sun/tools/javac/tree/Pretty.java

@@ -1467,7 +1467,7 @@ public void visitLiteral(JCLiteral tree) {
                     break;
                 case CHAR:
                     print('\'');
-                    print(Convert.quote(String.valueOf((char)((Number)tree.value).intValue())));
+                    print(Convert.quote((char)((Number)tree.value).intValue(), true));
                     print('\'');
                     break;
                 case BOOLEAN:

test/langtools/tools/javac/tree/PrettyCharLiteral.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2024, Google LLC. 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 8340568
+ * @summary Incorrect escaping of single quotes when pretty-printing character literals
+ * @modules jdk.compiler/com.sun.tools.javac.api
+ *          jdk.compiler/com.sun.tools.javac.file
+ *          jdk.compiler/com.sun.tools.javac.tree
+ *          jdk.compiler/com.sun.tools.javac.util
+ */
+
+import com.sun.tools.javac.file.JavacFileManager;
+import com.sun.tools.javac.tree.Pretty;
+import com.sun.tools.javac.tree.TreeMaker;
+import com.sun.tools.javac.util.Context;
+
+import java.io.IOException;
+import java.io.StringWriter;
+
+public class PrettyCharLiteral {
+    public static void main(String... args) throws Exception {
+        new PrettyCharLiteral().run();
+    }
+
+    private final TreeMaker make;
+
+    private PrettyCharLiteral() {
+        Context ctx = new Context();
+        JavacFileManager.preRegister(ctx);
+        this.make = TreeMaker.instance(ctx);
+    }
+
+    void run() throws Exception {
+        assertEquals(
+                prettyPrintLiteral('\''),
+                """
+                '\\''
+                """.trim());
+        assertEquals(
+                prettyPrintLiteral('"'),
+                """
+                '"'
+                """.trim());
+        assertEquals(
+                prettyPrintLiteral("'"),
+                """
+                "'"
+                """.trim());
+        assertEquals(
+                prettyPrintLiteral("\""),
+                """
+                "\\""
+                """.trim());
+    }
+
+    private void assertEquals(String actual, String expected) {
+        if (!actual.equals(expected)) {
+            throw new AssertionError("expected: " + expected + ", actual: " + actual);
+        }
+    }
+
+    private String prettyPrintLiteral(Object value) throws IOException {
+        StringWriter sw = new StringWriter();
+        new Pretty(sw, true).printExpr(make.Literal(value));
+        return sw.toString();
+    }
+}