Disable PHP warnings when running wp-cli

It is not uncommon to test sites on a development environment (locally or in a staging environment where others can see the work-in-progress). On a development environment, usually we have configured WP_DEBUG to be true. Here’s the sample of wp-config.php file in a development / test / staging environment…

<?php

<span class="hljs-function"><span class="hljs-keyword">define(<span class="hljs-string">'WP_CACHE'</span>, <span class="hljs-literal">false</span>)</span></span>;

<span class="hljs-function"><span class="hljs-keyword">define(<span class="hljs-string">'DB_NAME'</span>, <span class="hljs-string">'actual_db'</span>)</span></span>;
<span class="hljs-function"><span class="hljs-keyword">define(<span class="hljs-string">'DB_USER'</span>, <span class="hljs-string">'db_user'</span>)</span></span>;
<span class="hljs-function"><span class="hljs-keyword">define(<span class="hljs-string">'DB_PASSWORD'</span>, <span class="hljs-string">'Super_Secret_Passw0rd'</span>)</span></span>;
<span class="hljs-function"><span class="hljs-keyword">define(<span class="hljs-string">'DB_HOST'</span>, <span class="hljs-string">'localhost'</span>)</span></span>;

<span class="hljs-function"><span class="hljs-keyword">define(<span class="hljs-string">'WP_DEBUG'</span>, <span class="hljs-literal">true</span>)</span></span>;

/<span class="hljs-regexp">/ Other directives such as salts...</span>
<span class="hljs-regexp"></span>

While the above code is perfectly okay, if the site creates PHP warnings, it is a nuisance to see them repeatedly when using wp-cli multiple times. Even if you try configuring error_reporting to various values and turn off everything under the hood, you may still see PHP warning with the above code. It’s because the the warning are configured to be displayed when WP_DEBUG is set to true. In order to disable WP_DEBUG only for wp cli operations, the following modified code can be used…

<?php

define('WP_CACHE', false);

define('DB_NAME', 'actual_db');
define('DB_USER', 'db_user');
define('DB_PASSWORD', 'Super_Secret_Passw0rd');
define('DB_HOST', 'localhost');

if(!defined('$_SERVER["HTTP_HOST"]')) define('WP_DEBUG', false);
if( !defined( WP_DEBUG ) ) define('WP_DEBUG', true);

// Other directives such as salts...

Basically, we added the following code into the original code. The first line checks if it is a visit from a browser or from command line. When we evoke wp from command line, it doesn’t send HTTP_HOST. This way, we can tweak WP_DEBUG depending on the presence (or absence) of HTTP_HOST.

if(!defined('$_SERVER["HTTP_HOST"]')) define('WP_DEBUG', false);
if( !defined( WP_DEBUG ) ) define('WP_DEBUG', true);

The above code eliminates most PHP warnings when running WP-CLI. I hope this helps someone. There are multiple steps involved in getting a perfect development, local, test or staging environment for a WordPress site. If you are looking for a perfect hosting environment or a customized server to meet a better workflow for your developments, please get in touch.