diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index 9759438a0c..a5903b4187 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -1479,7 +1479,7 @@ class wpdb {
 			$port    = null;
 			$socket  = null;
 			$is_ipv6 = false;
-			
+
 			if ( $host_data = $this->parse_db_host( $this->dbhost ) ) {
 				list( $host, $port, $socket, $is_ipv6 ) = $host_data;
 			}
@@ -1621,9 +1621,10 @@ class wpdb {
 			return false;
 		}
 
+		$host = '';
 		foreach ( array( 'host', 'port', 'socket' ) as $component ) {
-			if ( array_key_exists( $component, $matches ) ) {
-				$$component = $matches[$component];
+			if ( ! empty( $matches[ $component ] ) ) {
+				$$component = $matches[ $component ];
 			}
 		}
 
diff --git a/tests/phpunit/tests/db.php b/tests/phpunit/tests/db.php
index 208c70ed5b..23fc87f8c4 100644
--- a/tests/phpunit/tests/db.php
+++ b/tests/phpunit/tests/db.php
@@ -1208,10 +1208,10 @@ class Tests_DB extends WP_UnitTestCase {
 
 			list( $parsed_host, $parsed_port, $parsed_socket, $parsed_is_ipv6 ) = $data;
 
-			$this->assertEquals( $host, $parsed_host );
-			$this->assertEquals( $port, $parsed_port );
-			$this->assertEquals( $socket, $parsed_socket );
-			$this->assertEquals( $is_ipv6, $parsed_is_ipv6 );
+			$this->assertSame( $host, $parsed_host );
+			$this->assertSame( $port, $parsed_port );
+			$this->assertSame( $socket, $parsed_socket );
+			$this->assertSame( $is_ipv6, $parsed_is_ipv6 );
 		}
 	}
 
@@ -1220,7 +1220,7 @@ class Tests_DB extends WP_UnitTestCase {
 			array(
 				'',    // DB_HOST
 				false, // Expect parse_db_host to bail for this hostname
-				null,  // Parsed host
+				'',    // Parsed host
 				null,  // Parsed port
 				null,  // Parsed socket
 				false, // is_ipv6
@@ -1228,7 +1228,7 @@ class Tests_DB extends WP_UnitTestCase {
 			array(
 				':3306',
 				false,
-				null,
+				'',
 				'3306',
 				null,
 				false,
@@ -1236,7 +1236,7 @@ class Tests_DB extends WP_UnitTestCase {
 			array(
 				':/tmp/mysql.sock',
 				false,
-				null,
+				'',
 				null,
 				'/tmp/mysql.sock',
 				false,