From f17d168a0f72211a9bfd9d3fa680713069871bb6 Mon Sep 17 00:00:00 2001
From: Gary Pendergast <gary@pento.net>
Date: Thu, 20 Nov 2014 01:46:24 +0000
Subject: [PATCH] WPDB: Force `STRICT_ALL_TABLES` to be enabled as soon as we
 connect to the MySQL server.

This improves data integrity when inserting and updating rows in the database, particularly when trying to insert emoji into posts stored with character sets that don't support emoji.

See #21212.

Built from https://develop.svn.wordpress.org/trunk@30400


git-svn-id: http://core.svn.wordpress.org/trunk@30396 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/wp-db.php | 71 ++++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 35 deletions(-)

diff --git a/wp-includes/wp-db.php b/wp-includes/wp-db.php
index 924ea5dcc0..0948a84b21 100644
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -566,8 +566,16 @@ class wpdb {
 	 * @access protected
 	 * @var array
 	 */
-	protected $incompatible_modes = array( 'NO_ZERO_DATE', 'ONLY_FULL_GROUP_BY',
-		'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 'TRADITIONAL' );
+	protected $incompatible_modes = array( 'NO_ZERO_DATE', 'ONLY_FULL_GROUP_BY', 'TRADITIONAL' );
+
+	/**
+	 * A list of required SQL modes.
+	 *
+	 * @since 4.1.0
+	 * @access protected
+	 * @var array
+	 */
+	protected $required_modes = array( 'STRICT_ALL_TABLES' );
 
 	/**
 	 * Whether to use mysqli over mysql.
@@ -778,31 +786,12 @@ class wpdb {
 	 */
 	public function set_sql_mode( $modes = array() ) {
 		if ( empty( $modes ) ) {
-			if ( $this->use_mysqli ) {
-				$res = mysqli_query( $this->dbh, 'SELECT @@SESSION.sql_mode' );
+			$modes = $this->get_var( "SELECT @@SESSION.sql_mode" );
+			if ( $modes ) {
+				$modes = $original_modes = explode( ',', $modes );
 			} else {
-				$res = mysql_query( 'SELECT @@SESSION.sql_mode', $this->dbh );
+				$modes = $original_modes = array();
 			}
-
-			if ( empty( $res ) ) {
-				return;
-			}
-
-			if ( $this->use_mysqli ) {
-				$modes_array = mysqli_fetch_array( $res );
-				if ( empty( $modes_array[0] ) ) {
-					return;
-				}
-				$modes_str = $modes_array[0];
-			} else {
-				$modes_str = mysql_result( $res, 0 );
-			}
-
-			if ( empty( $modes_str ) ) {
-				return;
-			}
-
-			$modes = explode( ',', $modes_str );
 		}
 
 		$modes = array_change_key_case( $modes, CASE_UPPER );
@@ -812,24 +801,36 @@ class wpdb {
 		 *
 		 * @since 3.9.0
 		 *
-		 * @see wpdb::$incompatible_modes
-		 *
 		 * @param array $incompatible_modes An array of incompatible modes.
 		 */
 		$incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
 
-		foreach( $modes as $i => $mode ) {
-			if ( in_array( $mode, $incompatible_modes ) ) {
-				unset( $modes[ $i ] );
+		/**
+		 * Filter the list of required SQL modes to include.
+		 *
+		 * @since 4.1.0
+		 *
+		 * @param array $required_modes An array of required modes.
+		 */
+		$required_modes = (array) apply_filters( 'required_sql_modes', $this->required_modes );
+
+		$modes = array_diff( $modes, $incompatible_modes );
+		$modes = array_unique( array_merge( $modes, $required_modes ) );
+
+		// Don't run SET SESSION if we have nothing to change.
+		if ( isset( $original_modes ) ) {
+			sort( $original_modes );
+			sort( $modes );
+			if ( $original_modes === $modes ) {
+				return;
 			}
 		}
 
 		$modes_str = implode( ',', $modes );
 
-		if ( $this->use_mysqli ) {
-			mysqli_query( $this->dbh, "SET SESSION sql_mode='$modes_str'" );
-		} else {
-			mysql_query( "SET SESSION sql_mode='$modes_str'", $this->dbh );
+		$this->query( "SET SESSION sql_mode='$modes_str'" );
+		if ( $this->last_error ) {
+			dead_db();
 		}
 	}
 
@@ -1482,8 +1483,8 @@ class wpdb {
 		} else if ( $this->dbh ) {
 			$this->has_connected = true;
 			$this->set_charset( $this->dbh );
-			$this->set_sql_mode();
 			$this->ready = true;
+			$this->set_sql_mode();
 			$this->select( $this->dbname, $this->dbh );
 
 			return true;