Debug, diagnose and solve

Last updated Jan 9, 2017


When customizing your theme with ACF functionality, you may experience some issues. These issues may resemble a blank page, a broken page, a value not being loaded or a visible error report. Although frustrating at first, these issues are in fact good feedback, and can be solved quickly. The process of solving these issues, of removing the bugs is known as debugging.

Exposing errors

Our first step to diagnosing any code related issue is to turn on error reporting. This will prevent the all too common “I’m getting no error message”  issue.

To enable error reporting, simply edit your wp-config.php file and look for the following:


 * For developers: WordPress debugging mode.
 * Change this to true to enable the display of notices during development.
 * It is strongly recommended that plugin and theme developers use WP_DEBUG
 * in their development environments.
define('WP_DEBUG', false);

By default, the WP_DEBUG setting is disabled, but to expose any potential PHP errors, you will need to enable it. You can do this by setting the value to true like so:

define('WP_DEBUG', true);

With error reporting now enabled, please refresh the page which contained the issue and look for any PHP errors. Each PHP error will contain the type of error, the file which caused the error and the line number that the error occurred on. If you see any PHP errors, please use this information to resolve the error.

You may find that the error is pointing to a line of code in your template or perhaps you have a section of code which is simply not performing the task you intended such as displaying an image. With an idea of where the issue is coming from, it’s time to debug the data!

Debugging data

It is likely that the issue your are experiencing is coming from a line of code which interacts with some ACF data. In this case, it is important to confirm that the data you are interacting with is as expected. This is possible by using the var_dump() function.

var_dump() is a native PHP function which displays structured, humanly readable information about one (or more) variables. This is particularly useful when dealing with arrays and objects as var_dump() displays their structure recursively giving you the best possible picture of what’s going on. Here’s an example of how to use var_dump() in context:


$image = get_field('image');

echo '<pre>';
    var_dump( $image );
echo '</pre>';


Please note that the above code also makes use of the pre tag to correctly render the line breaks and display an array or object in a more humanly readable format.

Now that you can see the data that your theme is interacting with, you may be able to spot where the problem lies. Perhaps you expected the value of $image to be a string containing the url, but upon inspection the value is an array containing lots of data.

JavaScript issues

Much of the ACF plugin uses JS to add interaction to form elements. For example, clicking on an image field ‘Select Image’ button will launch a popup. If an element seems unresponsive, it is most likely that a JS error exists on the page and is preventing the ACF JS from running.

Debugging JS is quite easy. Simply open the console log (via your browser’s inspector tool) and reload the page. With the console log open, look for any errors that may appear on page load or when interacting with the problem element. If an error appears, this is very useful information to include in your support ticket.

You may find that the JS error points to ‘line 1’ of a minified JS file. It is much more helpful to get the error line of an un-minified JS file. To do this, simply add the following code to your wp-config.php file:

define('SCRIPT_DEBUG', true);

This line of code will notify WP to load in the full versions of each JS script allowing more detailed JS error reporting.


Now that you can see the data, take a look at the code that is interacting with it. If the solution is not apparent at first, please spend a few minutes to research the issue by searching for the variable type (array, object, etc), the functions you are using and the issue you are experiencing. You may also find the solution over on the FAQ or Support pages.

If no solution can be found from the above, please contact our support team via the help desk on the support page and be sure to include any debugging information you have performed as this will greatly reduce the response time!