WPDB: Add a close() method to wpdb, for when the connection needs to be manually closed.

In the event that it was closed prematurely, `wpdb::query()` will re-open the connection automatically.

Fixes #34903.



git-svn-id: https://develop.svn.wordpress.org/trunk@36433 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/wp-db.php

@@ -3093,6 +3093,32 @@ class wpdb {
 		wp_die($message);
 	}
 
+
+	/**
+	 * Closes the current database connection.
+	 *
+	 * @since 4.5.0
+	 *
+	 * @return bool True if the connection was succesfully closed, false if it wasn't, or the connection doesn't exist.
+	 */
+	public function close() {
+		if ( ! $this->dbh ) {
+			return false;
+		}
+
+		if ( $this->use_mysqli ) {
+			$closed = mysqli_close( $this->dbh );
+		} else {
+			$closed = mysql_close( $this->dbh );
+		}
+
+		if ( $closed ) {
+			$this->dbh = null;
+		}
+
+		return $closed;
+	}
+
 	/**
 	 * Whether MySQL database is at least the required minimum version.
 	 *

tests/phpunit/tests/db.php

@@ -941,4 +941,20 @@ class Tests_DB extends WP_UnitTestCase {
 
 		$this->assertNull( $row );
 	}
+
+	/**
+	 * @ticket 34903
+	 */
+	function test_close() {
+		global $wpdb;
+
+		$this->assertTrue( $wpdb->close() );
+		$this->assertFalse( $wpdb->close() );
+
+		$wpdb->check_connection();
+
+		$this->assertTrue( $wpdb->close() );
+
+		$wpdb->check_connection();
+	}
 }