HV-591 Treating local and domain part separately

engine/src/main/java/org/hibernate/validator/internal/constraintvalidators/EmailValidator.java

@@ -2,11 +2,14 @@
 
 import java.net.IDN;
 import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import javax.validation.ConstraintValidator;
 import javax.validation.ConstraintValidatorContext;
 
 import org.hibernate.validator.constraints.Email;
 
+import static java.util.regex.Pattern.CASE_INSENSITIVE;
+
 /**
  * Checks that a given character sequence (e.g. string) is a well-formed email address.
  * <p>
@@ -23,16 +26,21 @@
  */
 public class EmailValidator implements ConstraintValidator<Email, CharSequence> {
 	private static String ATOM = "[a-z0-9!#$%&'*+/=?^_`{|}~-]";
-	private static String DOMAIN = "(" + ATOM + "+(\\." + ATOM + "+)*";
+	private static String DOMAIN = ATOM + "+(\\." + ATOM + "+)*";
 	private static String IP_DOMAIN = "\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\]";
 
-	private java.util.regex.Pattern pattern = java.util.regex.Pattern.compile(
-			"^" + ATOM + "+(\\." + ATOM + "+)*@"
-					+ DOMAIN
-					+ "|"
-					+ IP_DOMAIN
-					+ ")$",
-			java.util.regex.Pattern.CASE_INSENSITIVE
+	/**
+	 * Regular expression for the local part of an email address (everything before '@')
+	 */
+	private Pattern localPattern = java.util.regex.Pattern.compile(
+			ATOM + "+(\\." + ATOM + "+)*", CASE_INSENSITIVE
+	);
+
+	/**
+	 * Regular expression for the domain part of an email address (everything after '@')
+	 */
+	private Pattern domainPattern = java.util.regex.Pattern.compile(
+			DOMAIN + "|" + IP_DOMAIN, CASE_INSENSITIVE
 	);
 
 	public void initialize(Email annotation) {
@@ -42,8 +50,37 @@ public boolean isValid(CharSequence value, ConstraintValidatorContext context) {
 		if ( value == null || value.length() == 0 ) {
 			return true;
 		}
-		String asciiString = IDN.toASCII( value.toString() );
-		Matcher m = pattern.matcher( asciiString );
-		return m.matches();
+
+		// split email at '@' and consider local and domain part separately
+		String[] emailParts = value.toString().split( "@" );
+		if ( emailParts.length != 2 ) {
+			return false;
+		}
+
+		// if we have a trailing dot in local or domain part we have an invalid email address.
+		// the regular expression match would take care of this, but IDN.toASCII drops trailing the trailing '.'
+		// (imo a bug in the implementation)
+		if ( emailParts[0].endsWith( "." ) || emailParts[1].endsWith( "." ) ) {
+			return false;
+		}
+
+		if ( !matchPart( emailParts[0], localPattern ) ) {
+			return false;
+		}
+
+		return matchPart( emailParts[1], domainPattern );
+	}
+
+	private boolean matchPart(String part, Pattern pattern) {
+		try {
+			part = IDN.toASCII( part );
+		}
+		catch ( IllegalArgumentException e ) {
+			// occurs when the label is too long (>63, even though it should probably be 64 - see http://www.rfc-editor.org/errata_search.php?rfc=3696,
+			// practically that should not be a problem)
+			return false;
+		}
+		Matcher matcher = pattern.matcher( part );
+		return matcher.matches();
 	}
 }

engine/src/test/java/org/hibernate/validator/test/internal/constraintvalidators/EmailValidatorTest.java

@@ -147,6 +147,12 @@ public void testEmailRegExp() {
 		assertOrgAddressesAreNotValid( violations );
 	}
 
+	@Test
+	@TestForIssue(jiraKey = "HV-591")
+	public void testEmailAddressLength() {
+		isValidEmail( "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@hibernate.org" );
+	}
+
 	private void assertOrgAddressesAreNotValid(Set<ConstraintViolation<EmailContainer>> violations) {
 		assertNumberOfViolations( violations, 1 );
 		assertCorrectConstraintViolationMessages( violations, "ORG addresses are not valid" );
@@ -168,6 +174,7 @@ private void isInvalidEmail(CharSequence email) {
 		isInvalidEmail( email, "Expected a invalid email." );
 	}
 
+	@SuppressWarnings("unused")
 	private static abstract class EmailContainer {
 		public String email;