[DBAL-2546] Bind result variables after each execution in order to prevent string truncation

lib/Doctrine/DBAL/Driver/Mysqli/MysqliStatement.php

@@ -168,9 +168,6 @@ class MysqliStatement implements \IteratorAggregate, Statement
         if (null === $this->_columnNames) {
             $meta = $this->_stmt->result_metadata();
             if (false !== $meta) {
-                // We have a result.
-                $this->_stmt->store_result();
-
                 $columnNames = array();
                 foreach ($meta->fetch_fields() as $col) {
                     $columnNames[] = $col->name;
@@ -178,7 +175,29 @@ class MysqliStatement implements \IteratorAggregate, Statement
                 $meta->free();
 
                 $this->_columnNames = $columnNames;
-                $this->_rowBindedValues = array_fill(0, count($columnNames), null);
+            } else {
+                $this->_columnNames = false;
+            }
+        }
+
+        if (false !== $this->_columnNames) {
+            // Store result of every execution which has it. Otherwise it will be impossible
+            // to execute a new statement in case if the previous one has non-fetched rows
+            // @link http://dev.mysql.com/doc/refman/5.7/en/commands-out-of-sync.html
+            $this->_stmt->store_result();
+
+            // Bind row values _after_ storing the result. Otherwise, if mysqli is compiled with libmysql,
+            // it will have to allocate as much memory as it may be needed for the given column type
+            // (e.g. for a LONGBLOB field it's 4 gigabytes)
+            // @link https://bugs.php.net/bug.php?id=51386#1270673122
+            //
+            // Make sure that the values are bound after each execution. Otherwise, if closeCursor() has been
+            // previously called on the statement, the values are unbound making the statement unusable.
+            //
+            // It's also important that row values are bound after _each_ call to store_result(). Otherwise,
+            // if mysqli is compiled with libmysql, subsequently fetched string values will get truncated
+            // to the length of the ones fetched during the previous execution.
+            $this->_rowBindedValues = array_fill(0, count($this->_columnNames), null);
 
             $refs = array();
             foreach ($this->_rowBindedValues as $key => &$value) {
@@ -188,9 +207,6 @@ class MysqliStatement implements \IteratorAggregate, Statement
             if (!call_user_func_array(array($this->_stmt, 'bind_result'), $refs)) {
                 throw new MysqliException($this->_stmt->error, $this->_stmt->sqlstate, $this->_stmt->errno);
             }
-            } else {
-                $this->_columnNames = false;
-            }
         }
 
         return true;

tests/Doctrine/Tests/DBAL/Functional/StatementTest.php

@@ -53,4 +53,37 @@ class StatementTest extends \Doctrine\Tests\DbalFunctionalTestCase
 
         $this->assertFalse($value);
     }
+
+    public function testReuseStatementWithLongerResults()
+    {
+        $sm = $this->_conn->getSchemaManager();
+        $table = new Table('stmt_test_longer_results');
+        $table->addColumn('param', 'string');
+        $table->addColumn('val', 'text');
+        $sm->createTable($table);
+
+        $row1 = array(
+            'param' => 'param1',
+            'val' => 'X',
+        );
+        $this->_conn->insert('stmt_test_longer_results', $row1);
+
+        $stmt = $this->_conn->prepare('SELECT param, val FROM stmt_test_longer_results ORDER BY param');
+        $stmt->execute();
+        $this->assertArraySubset(array(
+            array('param1', 'X'),
+        ), $stmt->fetchAll(\PDO::FETCH_NUM));
+
+        $row2 = array(
+            'param' => 'param2',
+            'val' => 'A bit longer value',
+        );
+        $this->_conn->insert('stmt_test_longer_results', $row2);
+
+        $stmt->execute();
+        $this->assertArraySubset(array(
+            array('param1', 'X'),
+            array('param2', 'A bit longer value'),
+        ), $stmt->fetchAll(\PDO::FETCH_NUM));
+    }
 }