From 923c6c981bec3da7e012a85b92b2ee26e0ee1be9 Mon Sep 17 00:00:00 2001
From: Gary Pendergast <pento@git.wordpress.org>
Date: Wed, 6 May 2015 05:00:39 +0000
Subject: [PATCH] WPDB: Allow queries to reference tables in the
 `dbname.tablename` format, and allow table names to contain any valid
 character, rather than just ASCII.

Props pento, willstedt for the initial patch.

See #32090.



git-svn-id: https://develop.svn.wordpress.org/trunk@32368 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/wp-db.php  | 17 ++++++++++-------
 tests/phpunit/tests/db.php | 10 ++++++++--
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index 4be05e6ec6..c6ceabab1c 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -2266,7 +2266,10 @@ class wpdb {
 		}
 
 		$charsets = $columns = array();
-		$results = $this->get_results( "SHOW FULL COLUMNS FROM `$table`" );
+
+		$table_parts = explode( '.', $table );
+		$table = '`' . implode( '`.`', $table_parts ) . '`';
+		$results = $this->get_results( "SHOW FULL COLUMNS FROM $table" );
 		if ( ! $results ) {
 			return new WP_Error( 'wpdb_get_table_charset_failure' );
 		}
@@ -2838,16 +2841,16 @@ class wpdb {
 				. '|REPLACE(?:\s+LOW_PRIORITY|\s+DELAYED)?(?:\s+INTO)?'
 				. '|UPDATE(?:\s+LOW_PRIORITY)?(?:\s+IGNORE)?'
 				. '|DELETE(?:\s+LOW_PRIORITY|\s+QUICK|\s+IGNORE)*(?:\s+FROM)?'
-				. ')\s+`?([\w-]+)`?/is', $query, $maybe ) ) {
-			return $maybe[1];
+				. ')\s+((?:[0-9a-zA-Z$_.`]|[\xC2-\xDF][\x80-\xBF])+)/is', $query, $maybe ) ) {
+			return str_replace( '`', '', $maybe[1] );
 		}
 
 		// SHOW TABLE STATUS and SHOW TABLES
 		if ( preg_match( '/^\s*(?:'
 				. 'SHOW\s+TABLE\s+STATUS.+(?:LIKE\s+|WHERE\s+Name\s*=\s*)'
 				. '|SHOW\s+(?:FULL\s+)?TABLES.+(?:LIKE\s+|WHERE\s+Name\s*=\s*)'
-				. ')\W([\w-]+)\W/is', $query, $maybe ) ) {
-			return $maybe[1];
+				. ')\W((?:[0-9a-zA-Z$_.`]|[\xC2-\xDF][\x80-\xBF])+)\W/is', $query, $maybe ) ) {
+			return str_replace( '`', '', $maybe[1] );
 		}
 
 		// Big pattern for the rest of the table-related queries.
@@ -2865,8 +2868,8 @@ class wpdb {
 				. '|LOAD\s+DATA.*INFILE.*INTO\s+TABLE'
 				. '|(?:GRANT|REVOKE).*ON\s+TABLE'
 				. '|SHOW\s+(?:.*FROM|.*TABLE)'
-				. ')\s+\(*\s*`?([\w-]+)`?\s*\)*/is', $query, $maybe ) ) {
-			return $maybe[1];
+				. ')\s+\(*\s*((?:[0-9a-zA-Z$_.`]|[\xC2-\xDF][\x80-\xBF])+)\s*\)*/is', $query, $maybe ) ) {
+			return str_replace( '`', '', $maybe[1] );
 		}
 
 		return false;
diff --git a/tests/phpunit/tests/db.php b/tests/phpunit/tests/db.php
index ce0a4a519d..a8524aa2cb 100644
--- a/tests/phpunit/tests/db.php
+++ b/tests/phpunit/tests/db.php
@@ -526,6 +526,7 @@ class Tests_DB extends WP_UnitTestCase {
 	 */
 	function data_get_table_from_query() {
 		$table = 'a_test_table_name';
+		$db_table = '`a_test_db`.`another_test_table`';
 
 		$queries = array(
 			// Basic
@@ -628,8 +629,13 @@ class Tests_DB extends WP_UnitTestCase {
 			"SHOW INDEX FROM $table",
 		);
 
-		foreach ( $queries as &$query ) {
-			$query = array( $query, $table );
+		$querycount = count( $queries );
+		for ( $ii = 0; $ii < $querycount; $ii++ ) {
+			$db_query = str_replace( $table, $db_table, $queries[ $ii ] );
+			$expected_db_table = str_replace( '`', '', $db_table );
+
+			$queries[ $ii ] = array( $queries[ $ii ], $table );
+			$queries[] = array( $db_query, $expected_db_table );
 		}
 		return $queries;
 	}