Fix SQL formatting bug where a newline is missing after a single-line comment

Author: pdxzzz

hibernate-core/src/main/java/org/hibernate/engine/jdbc/internal/BasicFormatterImpl.java

@@ -76,20 +76,21 @@ public String perform() {
 						token = tokens.nextToken();
 					}
 					while ( !"\n".equals( token ) && tokens.hasMoreTokens() );
+					result.append( "\n" );
 				}
 
 				lcToken = token.toLowerCase( Locale.ROOT );
 				switch ( lcToken ) {
 					case "'":
 					case "`":
 					case "\"":
-						appendUntilToken(lcToken);
+						appendUntilToken( lcToken );
 						misc();
 						break;
 					// SQL Server uses "[" and "]" to escape reserved words
 					// see SQLServerDialect.openQuote and SQLServerDialect.closeQuote
 					case "[":
-						appendUntilToken("]");
+						appendUntilToken( "]" );
 						misc();
 						break;
 

hibernate-core/src/test/java/org/hibernate/orm/test/jdbc/util/BasicFormatterTest.java

@@ -78,6 +78,20 @@ public void testProblematic() {
 		assertNoLoss( "select * from ((select e.id from Entity e union all select e.id from Entity e) union select e.id from Entity e) grp" );
 	}
 
+	@Test
+	public void  testSingleLineComment(){
+		assertNoLoss("CREATE TRIGGER before_employee_delete\n"
+					+ "BEFORE DELETE ON employees\n"
+					+ "FOR EACH ROW\n"
+					+ "BEGIN\n"
+					+ "    -- abcd\n"
+					+ "    IF EXISTS (SELECT 1 FROM orders WHERE employee_id = OLD.id) THEN\n"
+					+ "        SIGNAL SQLSTATE '45000'\n"
+					+ "        SET MESSAGE_TEXT = 'Cannot delete employee because they have related orders';\n"
+					+ "    END IF;\n"
+					+ "END ");
+	}
+
 	private void assertNoLoss(String query) {
 		String formattedQuery = FormatStyle.BASIC.getFormatter().format( query );
 		StringTokenizer formatted = new StringTokenizer( formattedQuery, " \t\n\r\f()" );