count rows produced instead of getRow() in printRecords(ResultSet)

Author: rootvector2

src/main/java/org/apache/commons/csv/CSVPrinter.java

@@ -502,7 +502,11 @@ public void printRecords(final Object... values) throws IOException {
      */
     public void printRecords(final ResultSet resultSet) throws SQLException, IOException {
         final int columnCount = resultSet.getMetaData().getColumnCount();
-        while (resultSet.next() && format.useRow(resultSet.getRow())) {
+        // Count the rows produced here instead of ResultSet.getRow(): getRow() is the absolute cursor
+        // position, which is optional for TYPE_FORWARD_ONLY result sets and returns 0 there, silently
+        // disabling maxRows. Mirrors the row-produced counter the parser uses (CSV-327).
+        long rowCount = 0;
+        while (format.useRow(rowCount + 1) && resultSet.next()) {
             lock.lock();
             try {
                 for (int i = 1; i <= columnCount; i++) {
@@ -523,6 +527,7 @@ public void printRecords(final ResultSet resultSet) throws SQLException, IOExcep
             } finally {
                 lock.unlock();
             }
+            rowCount++;
         }
     }
 

src/test/java/org/apache/commons/csv/CSVPrinterTest.java

@@ -51,6 +51,7 @@
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.sql.Types;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.HashSet;
@@ -964,6 +965,30 @@ void testJdbcPrinterWithResultSetMetaData(final long maxRows) throws IOException
         }
     }
 
+    @Test
+    void testJdbcPrinterWithResultSetWithoutRowNumber() throws IOException, SQLException {
+        // JDBC makes ResultSet.getRow() optional for TYPE_FORWARD_ONLY result sets, where a driver may return 0.
+        // maxRows must still cap the output by rows produced rather than by getRow().
+        final StringWriter sw = new StringWriter();
+        final CSVFormat format = CSVFormat.DEFAULT.builder().setMaxRows(2).get();
+        try (SimpleResultSet resultSet = new SimpleResultSet() {
+            @Override
+            public int getRow() {
+                return 0;
+            }
+        }) {
+            resultSet.addColumn("ID", Types.INTEGER, 10, 0);
+            for (int i = 1; i <= 4; i++) {
+                resultSet.addRow(i);
+            }
+            try (CSVPrinter printer = new CSVPrinter(sw, format)) {
+                printer.printRecords(resultSet);
+                assertEquals(2, printer.getRecordCount());
+            }
+        }
+        assertEquals("1" + RECORD_SEPARATOR + "2" + RECORD_SEPARATOR, sw.toString());
+    }
+
     @Test
     void testJira135_part1() throws IOException {
         final CSVFormat format = CSVFormat.DEFAULT.withRecordSeparator('\n').withQuote(DQUOTE_CHAR).withEscape(BACKSLASH);