From 01356e100eb02ac866806e2db6b440ca0f0fb1c9 Mon Sep 17 00:00:00 2001
From: Gary Pendergast <pento@git.wordpress.org>
Date: Tue, 24 May 2016 05:23:06 +0000
Subject: [PATCH] Database: Don't generate unnecessary warnings in
 `wpdb::query()`.

In the event that the database has gone away for some reason, calls to `mysqli_errno()` and `mysqli_error()` (and their `ext/mysql` equivalents, of course), will generate PHP warnings, which are unsightly, and not how we do things in these parts.

Props mbijon, craig-ralston for the original patch.

Fixes #23085.



git-svn-id: https://develop.svn.wordpress.org/trunk@37548 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/wp-db.php | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index cffa68452e..c9fe6a31ad 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -1719,18 +1719,28 @@ class wpdb {
 
 		$this->check_current_query = true;
 
-		// Keep track of the last query for debug..
+		// Keep track of the last query for debug.
 		$this->last_query = $query;
 
 		$this->_do_query( $query );
 
-		// MySQL server has gone away, try to reconnect
+		// MySQL server has gone away, try to reconnect.
 		$mysql_errno = 0;
 		if ( ! empty( $this->dbh ) ) {
 			if ( $this->use_mysqli ) {
-				$mysql_errno = mysqli_errno( $this->dbh );
+				if ( $this->dbh instanceof mysqli ) {
+					$mysql_errno = mysqli_errno( $this->dbh );
+				} else {
+					// $dbh is defined, but isn't a real connection.
+					// Something has gone horribly wrong, let's try a reconnect.
+					$mysql_errno = 2006;
+				}
 			} else {
-				$mysql_errno = mysql_errno( $this->dbh );
+				if ( is_resource( $this->dbh ) ) {
+					$mysql_errno = mysql_errno( $this->dbh );
+				} else {
+					$mysql_errno = 2006;
+				}
 			}
 		}
 
@@ -1743,11 +1753,19 @@ class wpdb {
 			}
 		}
 
-		// If there is an error then take note of it..
+		// If there is an error then take note of it.
 		if ( $this->use_mysqli ) {
-			$this->last_error = mysqli_error( $this->dbh );
+			if ( $this->dbh instanceof mysqli ) {
+				$this->last_error = mysqli_error( $this->dbh );
+			} else {
+				$this->last_error = __( 'Unable to retrieve the error message from MySQL' );
+			}
 		} else {
-			$this->last_error = mysql_error( $this->dbh );
+			if ( is_resource( $this->dbh ) ) {
+				$this->last_error = mysql_error( $this->dbh );
+			} else {
+				$this->last_error = __( 'Unable to retrieve the error message from MySQL' );
+			}
 		}
 
 		if ( $this->last_error ) {