Changes after Fuzz Testing useFmtOnly

src/main/java/com/microsoft/sqlserver/jdbc/ParameterUtils.java

@@ -87,7 +87,7 @@ static int scanSQLForChar(char ch, String sql, int offset) {
 
                     // Fall through - will fail next if and end up in default case
                 case '-':
-                    if (sql.charAt(offset) == '-') { // If '-- ... \n' comment
+                    if (offset >= 0 && offset < sql.length() && sql.charAt(offset) == '-') { // If '-- ... \n' comment
                         while (++offset < len) { // Go thru comment.
                             if (sql.charAt(offset) == '\n' || sql.charAt(offset) == '\r') {
                                 // If end of comment

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerFMTQuery.java

@@ -13,7 +13,10 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
+import org.antlr.v4.runtime.BaseErrorListener;
 import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.RecognitionException;
+import org.antlr.v4.runtime.Recognizer;
 import org.antlr.v4.runtime.Token;
 
 
@@ -89,25 +92,42 @@ String getFMTQuery() {
     private SQLServerFMTQuery() {};
 
     SQLServerFMTQuery(String userSql) throws SQLServerException {
-        if (null == userSql || userSql.length() == 0) {
+        if (null == userSql || 0 == userSql.length()) {
             SQLServerException.makeFromDriverError(null, this,
-                    SQLServerResource.getResource("R_noTokensFoundInUserQuery"), "", false);
+                    SQLServerResource.getResource("R_noTokensFoundInUserQuery"), null, false);
         }
         InputStream stream = new ByteArrayInputStream(userSql.getBytes(StandardCharsets.UTF_8));
         SQLServerLexer lexer = null;
         try {
             lexer = new SQLServerLexer(CharStreams.fromStream(stream));
         } catch (IOException e) {
-            SQLServerException.makeFromDriverError(null, userSql, e.getLocalizedMessage(), "", false);
+            SQLServerException.makeFromDriverError(null, userSql, e.getLocalizedMessage(), null, false);
         }
-
+        lexer.removeErrorListeners();
+        lexer.addErrorListener(new SQLServerErrorListener());
         this.tokenList = (ArrayList<? extends Token>) lexer.getAllTokens();
         if (tokenList.size() <= 0) {
             SQLServerException.makeFromDriverError(null, this,
-                    SQLServerResource.getResource("R_noTokensFoundInUserQuery"), "", false);
+                    SQLServerResource.getResource("R_noTokensFoundInUserQuery"), null, false);
         }
         SQLServerTokenIterator iter = new SQLServerTokenIterator(tokenList);
         this.prefix = SQLServerParser.getCTE(iter);
         SQLServerParser.parseQuery(iter, this);
     }
 }
+
+
+class SQLServerErrorListener extends BaseErrorListener {
+    static final private java.util.logging.Logger logger = java.util.logging.Logger
+            .getLogger("com.microsoft.sqlserver.jdbc.internals.SQLServerFMTQuery");
+
+    @Override
+    public void syntaxError(Recognizer<?, ?> recognizer, Object offendingSymbol, int line, int charPositionInLine,
+            String msg, RecognitionException e) {
+        if (logger.isLoggable(java.util.logging.Level.FINE)) {
+            logger.fine("Error occured during token parsing: " + msg);
+            logger.fine("line " + line + ":" + charPositionInLine + " token recognition error at: "
+                    + offendingSymbol.toString());
+        }
+    }
+}