Merge branch '3.1-stable' into develop

Conflicts resolved:
	.travis.yml
	system/core/CodeIgniter.php
	system/database/drivers/oci8/oci8_forge.php
	system/database/drivers/pdo/subdrivers/pdo_oci_forge.php
	system/helpers/path_helper.php
	system/libraries/Email.php
	user_guide_src/source/changelog.rst
	user_guide_src/source/conf.py
	user_guide_src/source/contributing/index.rst
	user_guide_src/source/general/requirements.rst
	user_guide_src/source/general/styleguide.rst
	user_guide_src/source/installation/downloads.rst
	user_guide_src/source/installation/upgrade_310.rst
	user_guide_src/source/installation/upgrading.rst

18 files changed, 172 insertions, 135 deletions

diff --git a/system/database/drivers/cubrid/cubrid_forge.php b/system/database/drivers/cubrid/cubrid_forge.php
index 8262beb6b..46a3b2185 100644
--- a/system/database/drivers/cubrid/cubrid_forge.php
+++ b/system/database/drivers/cubrid/cubrid_forge.php
@@ -178,6 +178,9 @@ class CI_DB_cubrid_forge extends CI_DB_forge {
 				$attributes['TYPE'] = 'INTEGER';
 				$attributes['UNSIGNED'] = FALSE;
 				return;
+			case 'LONGTEXT':
+				$attributes['TYPE'] = 'STRING';
+				return;
 			default: return;
 		}
 	}
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index 72e31e00d..76f58564b 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -159,6 +159,7 @@ class CI_DB_mssql_driver extends CI_DB {
 		if (mssql_select_db('['.$database.']', $this->conn_id))
 		{
 			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
diff --git a/system/database/drivers/mssql/mssql_forge.php b/system/database/drivers/mssql/mssql_forge.php
index 24d1fc204..91b5794bc 100644
--- a/system/database/drivers/mssql/mssql_forge.php
+++ b/system/database/drivers/mssql/mssql_forge.php
@@ -113,6 +113,11 @@ class CI_DB_mssql_forge extends CI_DB_forge {
 	 */
 	protected function _attr_type(&$attributes)
 	{
+		if (isset($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') !== FALSE)
+		{
+			unset($attributes['CONSTRAINT']);
+		}
+
 		switch (strtoupper($attributes['TYPE']))
 		{
 			case 'MEDIUMINT':
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index d903406d1..70b4f68ba 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -220,6 +220,7 @@ class CI_DB_mysql_driver extends CI_DB {
 		if (mysql_select_db($database, $this->conn_id))
 		{
 			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index 431bce50a..168533240 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -263,6 +263,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 		if ($this->conn_id->select_db($database))
 		{
 			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index 59f0e8456..df7e0848a 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -559,23 +559,29 @@ class CI_DB_oci8_driver extends CI_DB {
 	 */
 	public function error()
 	{
-		/* oci_error() returns an array that already contains the
-		 * 'code' and 'message' keys, so we can just return it.
-		 */
+		// oci_error() returns an array that already contains
+		// 'code' and 'message' keys, but it can return false
+		// if there was no error ....
 		if (is_resource($this->curs_id))
 		{
-			return oci_error($this->curs_id);
+			$error = oci_error($this->curs_id);
 		}
 		elseif (is_resource($this->stmt_id))
 		{
-			return oci_error($this->stmt_id);
+			$error = oci_error($this->stmt_id);
 		}
 		elseif (is_resource($this->conn_id))
 		{
-			return oci_error($this->conn_id);
+			$error = oci_error($this->conn_id);
+		}
+		else
+		{
+			$error = oci_error();
 		}
 
-		return oci_error();
+		return is_array($error)
+			? $error
+			: array('code' => '', 'message' => '');
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/oci8/oci8_forge.php b/system/database/drivers/oci8/oci8_forge.php
index 989c7a8b7..23e025757 100644
--- a/system/database/drivers/oci8/oci8_forge.php
+++ b/system/database/drivers/oci8/oci8_forge.php
@@ -182,5 +182,4 @@ class CI_DB_oci8_forge extends CI_DB_forge {
 			default: return;
 		}
 	}
-
 }
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index 19b7b744b..63df2963d 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -50,7 +50,7 @@ defined('BASEPATH') OR exit('No direct script access allowed');
  * @author		EllisLab Dev Team
  * @link		https://codeigniter.com/user_guide/database/
  */
-class CI_DB_odbc_driver extends CI_DB {
+class CI_DB_odbc_driver extends CI_DB_driver {
 
 	/**
 	 * Database driver
@@ -94,6 +94,22 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * ODBC result ID resource returned from odbc_prepare()
+	 *
+	 * @var	resource
+	 */
+	private $odbc_result;
+
+	/**
+	 * Values to use with odbc_execute() for prepared statements
+	 *
+	 * @var	array
+	 */
+	private $binds = array();
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Class constructor
 	 *
 	 * @param	array	$params
@@ -128,6 +144,74 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * Compile Bindings
+	 *
+	 * @param	string	$sql	SQL statement
+	 * @param	array	$binds	An array of values to bind
+	 * @return	string
+	 */
+	public function compile_binds($sql, $binds)
+	{
+		if (empty($binds) OR empty($this->bind_marker) OR strpos($sql, $this->bind_marker) === FALSE)
+		{
+			return $sql;
+		}
+		elseif ( ! is_array($binds))
+		{
+			$binds = array($binds);
+			$bind_count = 1;
+		}
+		else
+		{
+			// Make sure we're using numeric keys
+			$binds = array_values($binds);
+			$bind_count = count($binds);
+		}
+
+		// We'll need the marker length later
+		$ml = strlen($this->bind_marker);
+
+		// Make sure not to replace a chunk inside a string that happens to match the bind marker
+		if ($c = preg_match_all("/'[^']*'/i", $sql, $matches))
+		{
+			$c = preg_match_all('/'.preg_quote($this->bind_marker, '/').'/i',
+				str_replace($matches[0],
+					str_replace($this->bind_marker, str_repeat(' ', $ml), $matches[0]),
+					$sql, $c),
+				$matches, PREG_OFFSET_CAPTURE);
+
+			// Bind values' count must match the count of markers in the query
+			if ($bind_count !== $c)
+			{
+				return $sql;
+			}
+		}
+		elseif (($c = preg_match_all('/'.preg_quote($this->bind_marker, '/').'/i', $sql, $matches, PREG_OFFSET_CAPTURE)) !== $bind_count)
+		{
+			return $sql;
+		}
+
+		if ($this->bind_marker !== '?')
+		{
+			do
+			{
+				$c--;
+				$sql = substr_replace($sql, '?', $matches[0][$c][1], $ml);
+			}
+			while ($c !== 0);
+		}
+
+		if (FALSE !== ($this->odbc_result = odbc_prepare($this->conn_id, $sql)))
+		{
+			$this->binds = array_values($binds);
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Execute the query
 	 *
 	 * @param	string	$sql	an SQL query
@@ -135,7 +219,25 @@ class CI_DB_odbc_driver extends CI_DB {
 	 */
 	protected function _execute($sql)
 	{
-		return odbc_exec($this->conn_id, $sql);
+		if ( ! isset($this->odbc_result))
+		{
+			return odbc_exec($this->conn_id, $sql);
+		}
+		elseif ($this->odbc_result === FALSE)
+		{
+			return FALSE;
+		}
+
+		if (TRUE === ($success = odbc_execute($this->odbc_result, $this->binds)))
+		{
+			// For queries that return result sets, return the result_id resource on success
+			$this->is_write_type($sql) OR $success = $this->odbc_result;
+		}
+
+		$this->odbc_result = NULL;
+		$this->binds       = array();
+
+		return $success;
 	}
 
 	// --------------------------------------------------------------------
@@ -214,7 +316,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	 */
 	protected function _escape_str($str)
 	{
-		return remove_invisible_characters($str);
+		$this->db->display_error('db_unsupported_feature');
 	}
 
 	// --------------------------------------------------------------------
@@ -312,58 +414,6 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Update statement
-	 *
-	 * Generates a platform-specific update string from the supplied data
-	 *
-	 * @param	string	$table
-	 * @param	array	$values
-	 * @return	string
-	 */
-	protected function _update($table, $values)
-	{
-		$this->qb_limit = FALSE;
-		$this->qb_orderby = array();
-		return parent::_update($table, $values);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Truncate statement
-	 *
-	 * Generates a platform-specific truncate string from the supplied data
-	 *
-	 * If the database does not support the TRUNCATE statement,
-	 * then this method maps to 'DELETE FROM table'
-	 *
-	 * @param	string	$table
-	 * @return	string
-	 */
-	protected function _truncate($table)
-	{
-		return 'DELETE FROM '.$table;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Delete statement
-	 *
-	 * Generates a platform-specific delete string from the supplied data
-	 *
-	 * @param	string	$table
-	 * @return	string
-	 */
-	protected function _delete($table)
-	{
-		$this->qb_limit = FALSE;
-		return parent::_delete($table);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
@@ -372,5 +422,4 @@ class CI_DB_odbc_driver extends CI_DB {
 	{
 		odbc_close($this->conn_id);
 	}
-
 }
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index c6f84e0f9..c27607e55 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -126,7 +126,10 @@ class CI_DB_pdo_driver extends CI_DB {
 	 */
 	public function db_connect($persistent = FALSE)
 	{
-		$this->options[PDO::ATTR_PERSISTENT] = $persistent;
+		if ($persistent === TRUE)
+		{
+			$this->options[PDO::ATTR_PERSISTENT] = TRUE;
+		}
 
 		try
 		{
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php
index 5f854061d..b5b95078e 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php
@@ -178,6 +178,9 @@ class CI_DB_pdo_cubrid_forge extends CI_DB_pdo_forge {
 				$attributes['TYPE'] = 'INTEGER';
 				$attributes['UNSIGNED'] = FALSE;
 				return;
+			case 'LONGTEXT':
+				$attributes['TYPE'] = 'STRING';
+				return;
 			default: return;
 		}
 	}
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index 84695ee9b..9a1cbcaf4 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -126,7 +126,12 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 */
 	public function db_connect($persistent = FALSE)
 	{
-		$this->conn_id = parent::db_connect($persistent);
+		if ($persistent === TRUE)
+		{
+			log_message('debug', "dblib driver doesn't support persistent connections");
+		}
+
+		$this->conn_id = parent::db_connect(FALSE);
 
 		if ( ! is_object($this->conn_id))
 		{
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php
index d5dd9aad1..830200325 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php
@@ -111,6 +111,11 @@ class CI_DB_pdo_dblib_forge extends CI_DB_pdo_forge {
 	 */
 	protected function _attr_type(&$attributes)
 	{
+		if (isset($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') !== FALSE)
+		{
+			unset($attributes['CONSTRAINT']);
+		}
+
 		switch (strtoupper($attributes['TYPE']))
 		{
 			case 'MEDIUMINT':
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index 70f2bfd4e..38a5a8aff 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -218,6 +218,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 		if (FALSE !== $this->simple_query('USE '.$this->escape_identifiers($database)))
 		{
 			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php b/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php
index 94a52ffc8..705b1c711 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php
@@ -173,5 +173,4 @@ class CI_DB_pdo_oci_forge extends CI_DB_pdo_forge {
 			default: return;
 		}
 	}
-
 }
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
index 333448838..82554ec80 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
@@ -161,6 +161,19 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
+	 * Platform-dependant string escape
+	 *
+	 * @param	string
+	 * @return	string
+	 */
+	protected function _escape_str($str)
+	{
+		$this->db->display_error('db_unsupported_feature');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Determines if a query is a "write" type.
 	 *
 	 * @param	string	An SQL query string
@@ -213,72 +226,4 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	{
 		return 'SELECT column_name FROM information_schema.columns WHERE table_name = '.$this->escape($table);
 	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Update statement
-	 *
-	 * Generates a platform-specific update string from the supplied data
-	 *
-	 * @param	string	$table
-	 * @param	array	$values
-	 * @return	string
-	 */
-	protected function _update($table, $values)
-	{
-		$this->qb_limit = FALSE;
-		$this->qb_orderby = array();
-		return parent::_update($table, $values);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Truncate statement
-	 *
-	 * Generates a platform-specific truncate string from the supplied data
-	 *
-	 * If the database does not support the TRUNCATE statement,
-	 * then this method maps to 'DELETE FROM table'
-	 *
-	 * @param	string	$table
-	 * @return	string
-	 */
-	protected function _truncate($table)
-	{
-		return 'DELETE FROM '.$table;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Delete statement
-	 *
-	 * Generates a platform-specific delete string from the supplied data
-	 *
-	 * @param	string	the table name
-	 * @return	string
-	 */
-	protected function _delete($table)
-	{
-		$this->qb_limit = FALSE;
-		return parent::_delete($table);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * LIMIT
-	 *
-	 * Generates a platform-specific LIMIT clause
-	 *
-	 * @param	string	$sql	SQL Query
-	 * @return	string
-	 */
-	protected function _limit($sql)
-	{
-		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$this->qb_limit.' ', $sql);
-	}
-
 }
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php
index 602f895f1..56bf87f3a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php
@@ -111,6 +111,11 @@ class CI_DB_pdo_sqlsrv_forge extends CI_DB_pdo_forge {
 	 */
 	protected function _attr_type(&$attributes)
 	{
+		if (isset($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') !== FALSE)
+		{
+			unset($attributes['CONSTRAINT']);
+		}
+
 		switch (strtoupper($attributes['TYPE']))
 		{
 			case 'MEDIUMINT':
diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index 0cd9ce16d..c55d5f7b7 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -171,6 +171,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 		if ($this->_execute('USE '.$this->escape_identifiers($database)))
 		{
 			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
diff --git a/system/database/drivers/sqlsrv/sqlsrv_forge.php b/system/database/drivers/sqlsrv/sqlsrv_forge.php
index f915dad3e..4f0ce9d6f 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_forge.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_forge.php
@@ -111,6 +111,11 @@ class CI_DB_sqlsrv_forge extends CI_DB_forge {
 	 */
 	protected function _attr_type(&$attributes)
 	{
+		if (isset($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') !== FALSE)
+		{
+			unset($attributes['CONSTRAINT']);
+		}
+
 		switch (strtoupper($attributes['TYPE']))
 		{
 			case 'MEDIUMINT':