fix: fix pretty-printing of special characters in literals (#3209)

src/main/java/spoon/reflect/visitor/LiteralHelper.java

@@ -105,16 +105,6 @@ public static <T> String getLiteralToken(CtLiteral<T> literal) {
 	static void appendCharLiteral(StringBuilder sb, Character c, boolean mayContainsSpecialCharacter) {
 		if (!mayContainsSpecialCharacter) {
 			sb.append(c);
-		} else if (Character.UnicodeBlock.of(c) != Character.UnicodeBlock.BASIC_LATIN) {
-			if (c < 0x10) {
-				sb.append("\\u000" + Integer.toHexString(c));
-			} else if (c < 0x100) {
-				sb.append("\\u00" + Integer.toHexString(c));
-			} else if (c < 0x1000) {
-				sb.append("\\u0" + Integer.toHexString(c));
-			} else {
-				sb.append("\\u" + Integer.toHexString(c));
-			}
 		} else {
 			switch (c) {
 				case '\b':

src/test/java/spoon/test/literal/UnicodeBugTest.java

@@ -0,0 +1,45 @@
+package spoon.test.literal;
+
+import org.junit.Test;
+import spoon.Launcher;
+import spoon.processing.AbstractProcessor;
+import spoon.reflect.CtModel;
+import spoon.reflect.code.CtBinaryOperator;
+import spoon.reflect.code.CtCodeElement;
+import spoon.reflect.code.CtLiteral;
+import spoon.reflect.declaration.CtField;
+import spoon.reflect.visitor.filter.TypeFilter;
+import spoon.support.compiler.VirtualFile;
+
+import static org.junit.Assert.assertEquals;
+
+// bug case kindly provided by @Banbury
+// in https://github.com/INRIA/spoon/issues/3203
+public class UnicodeBugTest {
+
+	@Test
+	public void testUnicodeBug() {
+		Launcher launcher = new Launcher();
+		launcher.addInputResource(new VirtualFile("class A { String s = \"Hellö \" + \"Wörld!\"; }"));
+		launcher.buildModel();
+		launcher.addProcessor(new StringConcatProcessor());
+		launcher.process();
+		CtModel model = launcher.getModel();
+		CtField<?> field = model.getElements(new TypeFilter<>(CtField.class)).get(0);
+		assertEquals(field.toString(), "java.lang.String s = \"Hellö Wörld!\";");
+	}
+
+	private class StringConcatProcessor extends AbstractProcessor<CtLiteral<?>> {
+		@Override
+		public boolean isToBeProcessed(CtLiteral<?> candidate) {
+			return candidate.getType().isSubtypeOf(getFactory().Type().STRING) &&
+					candidate.getParent() instanceof CtBinaryOperator;
+		}
+
+		@Override
+		public void process(CtLiteral<?> element) {
+			CtCodeElement s = ((CtBinaryOperator<?>) element.getParent()).partiallyEvaluate();
+			element.getParent().replace(s);
+		}
+	}
+}

src/test/java/spoon/test/strings/StringLiteralTest.java

@@ -61,8 +61,8 @@ public void testSnippetFullClass() {
 		assertEquals("java.lang.String f0 = \"toto\";", f0.toString());
 		assertEquals("java.lang.String f1 = \"\\n\";", f1.toString());
 		assertEquals("char c1 = '\\n';", c1.toString());
-		assertEquals("java.lang.String f2 = \"\\u20ac\";", f2.toString());
-		assertEquals("char c2 = '\\u20ac';", c2.toString());
+		assertEquals("java.lang.String f2 = \"€\";", f2.toString());
+		assertEquals("char c2 = '€';", c2.toString());
 		assertEquals("java.lang.String f3 = \"€\";", f3.toString());
 		assertEquals("char c3 = '€';", c3.toString());
 		assertEquals("java.lang.String f4 = \"\\t\";", f4.toString());