[DBAL-2546] Prevent exception when fetching from closed cursor

lib/Doctrine/DBAL/Driver/IBMDB2/DB2Statement.php

@@ -48,6 +48,13 @@ class DB2Statement implements \IteratorAggregate, Statement
      */
     private $_defaultFetchMode = \PDO::FETCH_BOTH;
 
+    /**
+     * Indicates whether the statement is in the state when fetching results is possible
+     *
+     * @var bool
+     */
+    private $result = false;
+
     /**
      * DB2_BINARY, DB2_CHAR, DB2_DOUBLE, or DB2_LONG
      *
@@ -105,7 +112,13 @@ class DB2Statement implements \IteratorAggregate, Statement
 
         $this->_bindParam = array();
 
-        return db2_free_result($this->_stmt);
+        if (!db2_free_result($this->_stmt)) {
+            return false;
+        }
+
+        $this->result = false;
+
+        return true;
     }
 
     /**
@@ -164,6 +177,8 @@ class DB2Statement implements \IteratorAggregate, Statement
             throw new DB2Exception(db2_stmt_errormsg());
         }
 
+        $this->result = true;
+
         return $retval;
     }
 
@@ -194,6 +209,12 @@ class DB2Statement implements \IteratorAggregate, Statement
      */
     public function fetch($fetchMode = null)
     {
+        // do not try fetching from the statement if it's not expected to contain result
+        // in order to prevent exceptional situation
+        if (!$this->result) {
+            return false;
+        }
+
         $fetchMode = $fetchMode ?: $this->_defaultFetchMode;
         switch ($fetchMode) {
             case \PDO::FETCH_BOTH:

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

@@ -80,6 +80,13 @@ class MysqliStatement implements \IteratorAggregate, Statement
      */
     protected $_defaultFetchMode = PDO::FETCH_BOTH;
 
+    /**
+     * Indicates whether the statement is in the state when fetching results is possible
+     *
+     * @var bool
+     */
+    private $result = false;
+
     /**
      * @param \mysqli $conn
      * @param string  $prepareString
@@ -209,6 +216,8 @@ class MysqliStatement implements \IteratorAggregate, Statement
             }
         }
 
+        $this->result = true;
+
         return true;
     }
 
@@ -256,6 +265,12 @@ class MysqliStatement implements \IteratorAggregate, Statement
      */
     public function fetch($fetchMode = null)
     {
+        // do not try fetching from the statement if it's not expected to contain result
+        // in order to prevent exceptional situation
+        if (!$this->result) {
+            return false;
+        }
+
         $values = $this->_fetch();
         if (null === $values) {
             return false;
@@ -341,6 +356,7 @@ class MysqliStatement implements \IteratorAggregate, Statement
     public function closeCursor()
     {
         $this->_stmt->free_result();
+        $this->result = false;
 
         return true;
     }

lib/Doctrine/DBAL/Driver/OCI8/OCI8Statement.php

@@ -80,6 +80,13 @@ class OCI8Statement implements \IteratorAggregate, Statement
      */
     private $boundValues = array();
 
+    /**
+     * Indicates whether the statement is in the state when fetching results is possible
+     *
+     * @var bool
+     */
+    private $result = false;
+
     /**
      * Creates a new OCI8Statement that uses the given connection handle and SQL statement.
      *
@@ -176,12 +183,19 @@ class OCI8Statement implements \IteratorAggregate, Statement
      */
     public function closeCursor()
     {
+        // not having the result means there's nothing to close
+        if (!$this->result) {
+            return true;
+        }
+
         // emulate it by fetching and discarding rows, similarly to what PDO does in this case
         // @link http://php.net/manual/en/pdostatement.closecursor.php
         // @link https://github.com/php/php-src/blob/php-7.0.11/ext/pdo/pdo_stmt.c#L2075
         // deliberately do not consider multiple result sets, since doctrine/dbal doesn't support them
         while (oci_fetch($this->_sth));
 
+        $this->result = false;
+
         return true;
     }
 
@@ -235,6 +249,8 @@ class OCI8Statement implements \IteratorAggregate, Statement
             throw OCI8Exception::fromErrorInfo($this->errorInfo());
         }
 
+        $this->result = true;
+
         return $ret;
     }
 
@@ -263,6 +279,12 @@ class OCI8Statement implements \IteratorAggregate, Statement
      */
     public function fetch($fetchMode = null)
     {
+        // do not try fetching from the statement if it's not expected to contain result
+        // in order to prevent exceptional situation
+        if (!$this->result) {
+            return false;
+        }
+
         $fetchMode = $fetchMode ?: $this->_defaultFetchMode;
         if ( ! isset(self::$fetchModeMap[$fetchMode])) {
             throw new \InvalidArgumentException("Invalid fetch style: " . $fetchMode);
@@ -292,6 +314,12 @@ class OCI8Statement implements \IteratorAggregate, Statement
                 $fetchStructure = OCI_FETCHSTATEMENT_BY_COLUMN;
             }
 
+            // do not try fetching from the statement if it's not expected to contain result
+            // in order to prevent exceptional situation
+            if (!$this->result) {
+                return array();
+            }
+
             oci_fetch_all($this->_sth, $result, 0, -1,
                 self::$fetchModeMap[$fetchMode] | OCI_RETURN_NULLS | $fetchStructure | OCI_RETURN_LOBS);
 
@@ -308,6 +336,12 @@ class OCI8Statement implements \IteratorAggregate, Statement
      */
     public function fetchColumn($columnIndex = 0)
     {
+        // do not try fetching from the statement if it's not expected to contain result
+        // in order to prevent exceptional situation
+        if (!$this->result) {
+            return false;
+        }
+
         $row = oci_fetch_array($this->_sth, OCI_NUM | OCI_RETURN_NULLS | OCI_RETURN_LOBS);
 
         if (false === $row) {

lib/Doctrine/DBAL/Driver/SQLSrv/SQLSrvStatement.php

@@ -98,6 +98,13 @@ class SQLSrvStatement implements IteratorAggregate, Statement
      */
     private $lastInsertId;
 
+    /**
+     * Indicates whether the statement is in the state when fetching results is possible
+     *
+     * @var bool
+     */
+    private $result = false;
+
     /**
      * Append to any INSERT query to retrieve the last insert id.
      *
@@ -150,12 +157,19 @@ class SQLSrvStatement implements IteratorAggregate, Statement
      */
     public function closeCursor()
     {
+        // not having the result means there's nothing to close
+        if (!$this->result) {
+            return true;
+        }
+
         // emulate it by fetching and discarding rows, similarly to what PDO does in this case
         // @link http://php.net/manual/en/pdostatement.closecursor.php
         // @link https://github.com/php/php-src/blob/php-7.0.11/ext/pdo/pdo_stmt.c#L2075
         // deliberately do not consider multiple result sets, since doctrine/dbal doesn't support them
         while (sqlsrv_fetch($this->stmt));
 
+        $this->result = false;
+
         return true;
     }
 
@@ -211,6 +225,8 @@ class SQLSrvStatement implements IteratorAggregate, Statement
             sqlsrv_fetch($this->stmt);
             $this->lastInsertId->setId(sqlsrv_get_field($this->stmt, 0));
         }
+
+        $this->result = true;
     }
 
     /**
@@ -240,6 +256,12 @@ class SQLSrvStatement implements IteratorAggregate, Statement
      */
     public function fetch($fetchMode = null)
     {
+        // do not try fetching from the statement if it's not expected to contain result
+        // in order to prevent exceptional situation
+        if (!$this->result) {
+            return false;
+        }
+
         $args      = func_get_args();
         $fetchMode = $fetchMode ?: $this->defaultFetchMode;
 

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

@@ -44,15 +44,7 @@ class StatementTest extends \Doctrine\Tests\DbalFunctionalTestCase
         $stmt->execute();
         $stmt->closeCursor();
 
-        try {
-            $value = $stmt->fetchColumn();
-        } catch (\Exception $e) {
-            // some adapters trigger PHP error or throw adapter-specific exception in case of fetching
-            // from a closed cursor, which still proves that it has been closed
-            return;
-        }
-
-        $this->assertFalse($value);
+        $this->assertFalse($stmt->fetchColumn());
     }
 
     public function testReuseStatementWithLongerResults()