I’ve got a WordPress plugin running on my website and I need to modify one of its functions. I’m wondering if I should put the custom code in my theme’s functions.php file or if there’s a better approach.
Here’s the function I want to customize:
/**
* display_lesson_enrollment_form function.
*
* @access public
* @param mixed $lesson_id
* @return void
*/
function display_lesson_enrollment_form( $lesson_id ) {
$requirements_met = validate_lesson_requirements( $lesson_id );
if ( $requirements_met ) {
?><form method="POST" action="<?php echo esc_url( get_permalink() ); ?>">
<input type="hidden" name="<?php echo esc_attr( 'my_plugin_enroll_nonce' ); ?>" id="<?php echo esc_attr( 'my_plugin_enroll_nonce' ); ?>" value="<?php echo esc_attr( wp_create_nonce( 'my_plugin_enroll_nonce' ) ); ?>" />
<span><input name="lesson_enroll" type="submit" class="enroll-button" value="<?php echo apply_filters( 'enroll_button_text', __( 'Enroll in this Lesson', 'my-plugin' ) ); ?>"/></span>
</form><?php
} // End If Statement
} // End display_lesson_enrollment_form()
What’s the proper way to override this without breaking things when the plugin updates?
First, check if the plugin has action hooks or filters around that function. Well-coded plugins usually include hooks for customization. If there aren’t any, you can override the function in your theme’s functions.php using a function_exists() check. This prevents conflicts if the plugin gets deactivated. But seriously, create a child theme if you haven’t already - theme updates will wipe out your changes just like plugin updates do. Even better: build a small custom plugin for your modifications. It keeps everything modular and survives both theme and plugin updates. I’ve done this on several client sites and it’s saved me tons of headaches during maintenance.
Honestly, check if the plugin fires any actions before/after that function runs. Most decent plugins have hooks like before_enrollment_form you can use without touching the original code. If there aren’t any hooks, you’ll need to unhook the original function and replace it entirely - but that’s risky and will break when the plugin updates.
Don’t put plugin overrides in functions.php - it’s a maintenance nightmare. First, check if the plugin has action or filter hooks you can use instead of replacing the whole function. If you have to override it, wrap your custom version in if (!function_exists('display_lesson_enrollment_form')) then define your modified version. But honestly? Create a Must Use plugin instead. Drop a PHP file in /wp-content/mu-plugins/ with your override code. Your changes won’t break when themes or plugins update, and it loads before regular plugins so the override actually works. I’ve done this on tons of client sites and it’s bulletproof.