HV-1774 Do not interpret '$\A{1+1}' in message templates

Author: yrodiere

Diff for: engine/src/main/java/org/hibernate/validator/internal/engine/messageinterpolation/parser/ELState.java

@@ -56,7 +56,11 @@ public void handleEndTerm(char character, TokenCollector tokenCollector) throws
 	@Override
 	public void handleEscapeCharacter(char character, TokenCollector tokenCollector)
 			throws MessageDescriptorFormatException {
-		tokenCollector.transitionState( new EscapedState( this ) );
+		tokenCollector.appendToToken( EL_DESIGNATOR );
+		tokenCollector.appendToToken( character );
+		// Do not go back to this state after the escape: $\ is not the start of an EL expression
+		ParserState stateAfterEscape = new MessageState();
+		tokenCollector.transitionState( new EscapedState( stateAfterEscape ) );
 	}
 
 	@Override

Diff for: engine/src/test/java/org/hibernate/validator/test/internal/engine/messageinterpolation/TokenCollectorTest.java

@@ -8,7 +8,11 @@
 
 import org.hibernate.validator.internal.engine.messageinterpolation.InterpolationTermType;
 import org.hibernate.validator.internal.engine.messageinterpolation.parser.MessageDescriptorFormatException;
+import org.hibernate.validator.internal.engine.messageinterpolation.parser.Token;
 import org.hibernate.validator.internal.engine.messageinterpolation.parser.TokenCollector;
+
+import org.assertj.core.api.Assertions;
+import org.assertj.core.api.ListAssert;
 import org.testng.annotations.Test;
 
 /**
@@ -29,10 +33,25 @@ public void testParameterWithoutOpeningBraceThrowsException() throws Exception {
 	}
 
 	@Test(expectedExceptions = MessageDescriptorFormatException.class, expectedExceptionsMessageRegExp = "HV000168.*")
-	public void testELExpressionWithoutOpeningBraceThrowsException() throws Exception {
+	public void testELExpressionDollarThenClosingBraceThrowsException() throws Exception {
 		new TokenCollector( "$}", InterpolationTermType.EL );
 	}
 
+	@Test
+	public void testELExpressionDollarThenEscapeInterpretedAsLiterals() {
+		ListAssert<Token> assertion = Assertions.assertThat(
+				new TokenCollector( "$\\A{1+1}", InterpolationTermType.EL )
+						.getTokenList()
+		)
+				.hasSize( 2 );
+		assertion.element( 0 )
+				.returns( "$\\A", Token::getTokenValue )
+				.returns( false, Token::isParameter );
+		assertion.element( 1 )
+				.returns( "{1+1}", Token::getTokenValue )
+				.returns( false, Token::isParameter );
+	}
+
 	@Test(expectedExceptions = MessageDescriptorFormatException.class, expectedExceptionsMessageRegExp = "HV000168.*")
 	public void testTermWithoutClosingBraceThrowsException() throws Exception {
 		new TokenCollector( "{foo", InterpolationTermType.PARAMETER );