From de33d35d1f9ea6da45259b172d617bfcb07073d9 Mon Sep 17 00:00:00 2001
From: Gary Pendergast <pento@git.wordpress.org>
Date: Tue, 18 Nov 2014 03:37:23 +0000
Subject: [PATCH] WPDB: When a `db.php` drop-in is being used, and it doesn't
 explicitly define itself as connecting to MySQL, skip the character set
 checks. This ensures that existing drop-ins won't accidentally run checks
 that they don't support.

See #21212.


git-svn-id: https://develop.svn.wordpress.org/trunk@30375 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/wp-db.php          | 16 ++++++++++------
 tests/phpunit/tests/db/charset.php | 28 +++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index e297152092..924ea5dcc0 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -2211,7 +2211,7 @@ class wpdb {
 		$this->col_meta[ $table ] = $columns;
 
 		foreach ( $columns as $column ) {
-			if ( $column->Collation ) {
+			if ( ! empty( $column->Collation ) ) {
 				list( $charset ) = explode( '_', $column->Collation );
 				$charsets[ strtolower( $charset ) ] = true;
 			}
@@ -2237,7 +2237,7 @@ class wpdb {
 			$charset = key( $charsets );
 		} elseif ( 0 === $count ) {
 			// No charsets, assume this table can store whatever.
-			$charset = 'latin1';
+			$charset = false;
 		} else {
 			// More than one charset. Remove latin1 if present and recalculate.
 			unset( $charsets['latin1'] );
@@ -2291,6 +2291,11 @@ class wpdb {
 			return $charset;
 		}
 
+		// Skip this entirely if this isn't a MySQL database.
+		if ( false === $this->is_mysql ) {
+			return false;
+		}
+
 		if ( empty( $this->table_charset[ $table ] ) ) {
 			// This primes column information for us.
 			$table_charset = $this->get_table_charset( $table );
@@ -2378,13 +2383,12 @@ class wpdb {
 		foreach ( $data as &$value ) {
 			$charset = $value['charset'];
 
-			// latin1 will happily store anything.
-			if ( 'latin1' === $charset ) {
+			// Column isn't a string, or is latin1, which will will happily store anything.
+			if ( false === $charset || 'latin1' === $charset ) {
 				continue;
 			}
 
-			// Column or value isn't a string.
-			if ( false === $charset || ! is_string( $value['value'] ) ) {
+			if ( ! is_string( $value['value'] ) ) {
 				continue;
 			}
 
diff --git a/tests/phpunit/tests/db/charset.php b/tests/phpunit/tests/db/charset.php
index fcad682e04..00f6e0b963 100755
--- a/tests/phpunit/tests/db/charset.php
+++ b/tests/phpunit/tests/db/charset.php
@@ -231,7 +231,7 @@ class Tests_DB_Charset extends WP_UnitTestCase {
 	protected $table_and_column_defs = array(
 		array(
 			'definition'      => '( a INT, b FLOAT )',
-			'table_expected'  => 'latin1',
+			'table_expected'  => false,
 			'column_expected' => array( 'a' => false, 'b' => false )
 		),
 		array(
@@ -346,6 +346,32 @@ class Tests_DB_Charset extends WP_UnitTestCase {
 		self::$_wpdb->query( $drop );
 	}
 
+	/**
+	 * @dataProvider data_test_get_column_charset
+	 * @ticket 21212
+	 */
+	function test_get_column_charset_non_mysql( $drop, $create, $table, $columns ) {
+		self::$_wpdb->query( $drop );
+
+		if ( ! self::$_wpdb->has_cap( 'utf8mb4' ) && preg_match( '/utf8mb[34]/i', $create ) ) {
+			$this->markTestSkipped( "This version of MySQL doesn't support utf8mb4." );
+			return;
+		}
+
+		self::$_wpdb->is_mysql = false;
+
+		self::$_wpdb->query( $create );
+
+		$columns = array_keys( $columns );
+		foreach ( $columns as $column => $charset ) {
+			$this->assertEquals( false, self::$_wpdb->get_col_charset( $table, $column ) );
+		}
+
+		self::$_wpdb->query( $drop );
+
+		self::$_wpdb->is_mysql = true;
+	}
+
 	/**
 	 * @ticket 21212
 	 */