From a7d4abaedc27497d570ae06ddc9cdde05930ec15 Mon Sep 17 00:00:00 2001
From: Andrey Andreev <narf@devilix.net>
Date: Mon, 19 Oct 2015 14:39:44 +0300
Subject: Fix #4171 and a number of other transaction bugs

---
 system/database/DB_driver.php | 115 +++++++++++++++++++++++++++++++++---------
 1 file changed, 91 insertions(+), 24 deletions(-)

(limited to 'system/database/DB_driver.php')

diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index cc94edc16..0ea679432 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -668,7 +668,13 @@ abstract class CI_DB_driver {
 				{
 					do
 					{
+						$trans_depth = $this->_trans_depth;
 						$this->trans_complete();
+						if ($trans_depth === $this->_trans_depth)
+						{
+							log_message('error', 'Database: Failure during an automated transaction commit/rollback!');
+							break;
+						}
 					}
 					while ($this->_trans_depth !== 0);
 				}
@@ -813,24 +819,16 @@ abstract class CI_DB_driver {
 	 * Start Transaction
 	 *
 	 * @param	bool	$test_mode = FALSE
-	 * @return	void
+	 * @return	bool
 	 */
 	public function trans_start($test_mode = FALSE)
 	{
 		if ( ! $this->trans_enabled)
 		{
-			return;
-		}
-
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
-		{
-			$this->_trans_depth += 1;
-			return;
+			return FALSE;
 		}
 
-		$this->trans_begin($test_mode);
-		$this->_trans_depth += 1;
+		return $this->trans_begin($test_mode);
 	}
 
 	// --------------------------------------------------------------------
@@ -847,17 +845,6 @@ abstract class CI_DB_driver {
 			return FALSE;
 		}
 
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 1)
-		{
-			$this->_trans_depth -= 1;
-			return TRUE;
-		}
-		else
-		{
-			$this->_trans_depth = 0;
-		}
-
 		// The query() function will set this flag to FALSE in the event that a query failed
 		if ($this->_trans_status === FALSE OR $this->_trans_failure === TRUE)
 		{
@@ -875,8 +862,7 @@ abstract class CI_DB_driver {
 			return FALSE;
 		}
 
-		$this->trans_commit();
-		return TRUE;
+		return $this->trans_commit();
 	}
 
 	// --------------------------------------------------------------------
@@ -893,6 +879,87 @@ abstract class CI_DB_driver {
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * Begin Transaction
+	 *
+	 * @param	bool	$test_mode
+	 * @return	bool
+	 */
+	public function trans_begin($test_mode = FALSE)
+	{
+		if ( ! $this->trans_enabled)
+		{
+			return FALSE;
+		}
+		// When transactions are nested we only begin/commit/rollback the outermost ones
+		elseif ($this->_trans_depth > 0)
+		{
+			$this->_trans_depth++;
+			return TRUE;
+		}
+
+		// Reset the transaction failure flag.
+		// If the $test_mode flag is set to TRUE transactions will be rolled back
+		// even if the queries produce a successful result.
+		$this->_trans_failure = ($test_mode === TRUE);
+
+		if ($this->_trans_begin())
+		{
+			$this->_trans_depth++;
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Commit Transaction
+	 *
+	 * @return	bool
+	 */
+	public function trans_commit()
+	{
+		if ( ! $this->trans_enabled OR $this->_trans_depth === 0)
+		{
+			return FALSE;
+		}
+		// When transactions are nested we only begin/commit/rollback the outermost ones
+		elseif ($this->_trans_depth > 1 OR $this->_trans_commit())
+		{
+			$this->_trans_depth--;
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Rollback Transaction
+	 *
+	 * @return	bool
+	 */
+	public function trans_rollback()
+	{
+		if ( ! $this->trans_enabled OR $this->_trans_depth === 0)
+		{
+			return FALSE;
+		}
+		// When transactions are nested we only begin/commit/rollback the outermost ones
+		elseif ($this->_trans_depth > 1 OR $this->_trans_rollback())
+		{
+			$this->_trans_depth--;
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
 	/**
 	 * Compile Bindings
 	 *
-- 
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