fix: Remove escaping of ' in a CtLiteral<String> (#5070)

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

@@ -99,7 +99,7 @@ public static <T> String getLiteralToken(CtLiteral<T> literal) {
 			}
 			StringBuilder sb = new StringBuilder(10);
 			sb.append('\'');
-			appendCharLiteral(sb, (Character) literal.getValue(), mayContainsSpecialCharacter);
+			appendCharLiteral(sb, (Character) literal.getValue(), mayContainsSpecialCharacter, false);
 			sb.append('\'');
 			return sb.toString();
 		} else if (literal.getValue() instanceof String) {
@@ -120,7 +120,7 @@ public static <T> String getLiteralToken(CtLiteral<T> literal) {
 		}
 	}
 
-	static void appendCharLiteral(StringBuilder sb, Character c, boolean mayContainsSpecialCharacter) {
+	static void appendCharLiteral(StringBuilder sb, Character c, boolean mayContainsSpecialCharacter, boolean isInsideString) {
 		if (!mayContainsSpecialCharacter) {
 			sb.append(c);
 		} else {
@@ -144,7 +144,11 @@ static void appendCharLiteral(StringBuilder sb, Character c, boolean mayContains
 					sb.append("\\\""); //$NON-NLS-1$
 					break;
 				case '\'':
-					sb.append("\\'"); //$NON-NLS-1$
+					if (isInsideString) {
+						sb.append("'"); //$NON-NLS-1$
+					} else {
+						sb.append("\\'"); //$NON-NLS-1$
+					}
 					break;
 				case '\\': // take care not to display the escape as a potential
 					// real char
@@ -159,12 +163,11 @@ static void appendCharLiteral(StringBuilder sb, Character c, boolean mayContains
 	static String getStringLiteral(String value, boolean mayContainsSpecialCharacter) {
 		if (!mayContainsSpecialCharacter) {
 			return value;
-		} else {
-			StringBuilder sb = new StringBuilder(value.length() * 2);
-			for (int i = 0; i < value.length(); i++) {
-				appendCharLiteral(sb, value.charAt(i), mayContainsSpecialCharacter);
-			}
-			return sb.toString();
 		}
+		StringBuilder sb = new StringBuilder(value.length() * 2);
+		for (int i = 0; i < value.length(); i++) {
+			appendCharLiteral(sb, value.charAt(i), true, true);
+		}
+		return sb.toString();
 	}
 }

src/test/java/spoon/test/literal/LiteralTest.java

@@ -22,14 +22,16 @@
 import spoon.reflect.declaration.CtType;
 import spoon.reflect.code.CtLiteral;
 import spoon.reflect.factory.CodeFactory;
+import spoon.test.GitHubIssue;
 import spoon.test.literal.testclasses.Tacos;
 import spoon.Launcher;
 import spoon.reflect.code.LiteralBase;
+import spoon.reflect.cu.SourcePosition;
 import spoon.reflect.factory.TypeFactory;
 import spoon.reflect.declaration.CtClass;
 import org.junit.jupiter.api.Test;
 import spoon.testing.utils.ModelTest;
-
+import java.util.List;
 import java.util.TreeSet;
 
 import static spoon.testing.utils.ModelUtils.buildClass;
@@ -257,4 +259,27 @@ public void testLiteralBasePrinter(Factory factory) {
 		assertEquals("'c'", ctClass.getField("c1").getDefaultExpression().toString());
 		assertEquals("\"hello\"", ctClass.getField("s1").getDefaultExpression().toString());
 	}
+
+	@GitHubIssue(issueNumber = 5070, fixed = true)
+	void tooStrictEscaping() {
+		// contract: inside a string without a position ' are not escaped.
+		List<CtLiteral<?>> literals = Launcher.parseClass("class Foo { String s = \"'\"; }")
+				.getElements(new TypeFilter<>(CtLiteral.class));
+		CtLiteral<?> ctLiteral = literals.get(0);
+		ctLiteral.setPosition(SourcePosition.NOPOSITION);
+		String literal = (String) ctLiteral.getValue();
+		assertEquals("'", literal);
+		assertEquals("\"'\"", ctLiteral.toString());
+	}
+
+	@GitHubIssue(issueNumber = 5070, fixed = true)
+	void tooStrictEscapingCharTest() {
+		// contract: inside a string with a position ' are escaped.
+		List<CtLiteral<?>> literals = Launcher.parseClass("class Foo { char c = \'\\'\'; }")
+				.getElements(new TypeFilter<>(CtLiteral.class));
+		CtLiteral<?> ctLiteral = literals.get(0);
+		char literal = (char) ctLiteral.getValue();
+		assertEquals('\'', literal);
+		assertEquals("\'\\'\'", ctLiteral.toString());
+	}
 }