Added empty result set check to nextRowset()

source/pdo_sqlsrv/pdo_stmt.cpp

@@ -1067,6 +1067,14 @@ int pdo_sqlsrv_stmt_next_rowset( _Inout_ pdo_stmt_t *stmt TSRMLS_DC )
 
         SQLSRV_ASSERT( driver_stmt != NULL, "pdo_sqlsrv_stmt_next_rowset: driver_data object was null" );
 
+        // If SQLNumResultCols returns 0, the result set is empty. Normally this error is 
+        // handled in core_sqlsrv_fetch, but if the user calls nextRowset() before fetch()
+        // the error message won't show up unless we handle it here.
+        SQLSMALLINT has_fields = core::SQLNumResultCols( driver_stmt TSRMLS_CC );
+        CHECK_CUSTOM_ERROR( has_fields == 0, driver_stmt, SQLSRV_ERROR_NO_FIELDS ) {
+            throw core::CoreException();
+        }
+
         core_sqlsrv_next_result( static_cast<sqlsrv_stmt*>( stmt->driver_data ) TSRMLS_CC );
 
         // clear the current meta data since the new result will generate new meta data

test/functional/pdo_sqlsrv/pdo_empty_result_error.phpt

@@ -0,0 +1,96 @@
+--TEST--
+Test that calling nextRowset() on an empty result set produces the correct error message. Fix for Github 507.
+--SKIPIF--
+<?php require('skipif.inc'); ?>
+--FILE--
+<?php
+require_once("MsSetup.inc");
+
+$conn = new PDO( "sqlsrv:Server = $server; Database = $databaseName; ", $uid, $pwd );
+$conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
+
+$stmt = $conn->query("IF OBJECT_ID('TestEmptySetTable', 'U') IS NOT NULL DROP TABLE TestEmptySetTable");
+$stmt = $conn->query("CREATE TABLE TestEmptySetTable ([c1] nvarchar(10),[c2] nvarchar(10))");
+
+$stmt = $conn->query("INSERT INTO TestEmptySetTable (c1, c2) VALUES ('a', 'b')");
+$stmt = $conn->query("IF OBJECT_ID('TestEmptySetProc', 'P') IS NOT NULL DROP PROCEDURE TestEmptySetProc");
+$stmt = $conn->query("CREATE PROCEDURE TestEmptySetProc @a nvarchar(10), @b nvarchar(10)
+                      AS SET NOCOUNT ON
+                      BEGIN
+                          IF @b='b'
+                          BEGIN
+                              SELECT 'a' as testValue
+                          END
+                          ELSE
+                          BEGIN
+                              UPDATE TestEmptySetTable SET c2 = 'c' WHERE c1 = @a
+                          END
+                      END");
+
+// errors out when reaching the second nextRowset() call
+// returned error indicates there are no more results
+echo "Return a nonempty result set:\n";
+try
+{
+    $stmt = $conn->query("TestEmptySetProc @a='a', @b='b'");
+    $result = $stmt->fetchAll();
+    print_r($result);
+    $stmt->nextRowset();
+    $result = $stmt->fetchAll();
+    print_r($result);
+    $stmt->nextRowset();
+}
+catch(Exception $e)
+{
+    echo $e->getMessage()."\n";
+}
+
+// errors out indicating the result set contains no fields
+echo "Return an empty result set, call nextRowset on it before fetching anything:\n";
+try
+{
+    $stmt = $conn->query("TestEmptySetProc @a='a', @b='c'");
+    $stmt->nextRowset();
+}
+catch(Exception $e)
+{
+    echo $e->getMessage()."\n";
+}
+
+// errors out indicating the result set contains no fields
+echo "Return an empty result set, call fetch on it:\n";
+try
+{
+    $stmt = $conn->query("TestEmptySetProc @a='a', @b='c'");
+    $result = $stmt->fetchAll();
+    print_r($result);
+}
+catch(Exception $e)
+{
+    echo $e->getMessage()."\n";
+}
+
+$stmt = $conn->query("DROP TABLE TestEmptySetTable");
+$stmt = $conn->query("DROP PROCEDURE TestEmptySetProc");
+
+$conn = null;
+?>
+--EXPECT--
+Return a nonempty result set:
+Array
+(
+    [0] => Array
+        (
+            [testValue] => a
+            [0] => a
+        )
+
+)
+Array
+(
+)
+SQLSTATE[IMSSP]: There are no more results returned by the query.
+Return an empty result set, call nextRowset on it before fetching anything:
+SQLSTATE[IMSSP]: The active result for the query contains no fields.
+Return an empty result set, call fetch on it:
+SQLSTATE[IMSSP]: The active result for the query contains no fields.