Using Gravity Forms ‘gform_mailchimp_override_empty_fields’ PHP filter

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The gform_mailchimp_override_empty_fields filter allows you to prevent empty form fields from erasing values already stored in the mapped Mailchimp MMERGE fields when updating an existing subscriber.

Usage

A generic example of the filter, which runs for all Mailchimp feeds:

add_filter('gform_mailchimp_override_empty_fields', 'your_function_name', 10, 4);

To target a specific form, append the form ID to the hook name (format: gform_mailchimp_override_empty_fields_FORMID):

add_filter('gform_mailchimp_override_empty_fields_10', 'your_function_name', 10, 4);

Parameters

  • $override (boolean): The default is true.
  • $form (Form Object): The form currently being processed.
  • $entry (Entry Object): The entry currently being processed.
  • $feed (Feed Object): The feed currently being processed.

More information

See Gravity Forms Docs: gform_mailchimp_override_empty_fields

Examples

Override all feeds

This example shows how to apply the filter to all Mailchimp feeds:

add_filter('gform_mailchimp_override_empty_fields', '__return_false');

Override specific feed

This example shows how to target a specific Mailchimp feed:

add_filter('gform_mailchimp_override_empty_fields', function($override, $form, $entry, $feed) {
$feed_name = rgars($feed, 'meta/feedName');
return $feed_name == 'Your feed name' ? false : $override;
}, 10, 4);

Override feed for a specific form

This example shows how to target a specific Mailchimp feed for a specific form:

add_filter('gform_mailchimp_override_empty_fields_5', function($override, $form, $entry, $feed) {
$feed_name = rgars($feed, 'meta/feedName');
return $feed_name == 'Your feed name' ? false : $override;
}, 10, 4);

Override based on form field value

This example shows how to override the empty fields behavior based on a form field value:

add_filter('gform_mailchimp_override_empty_fields', function($override, $form, $entry, $feed) {
$field_value = rgar($entry, '1'); // Replace '1' with the field ID
return $field_value == 'Your desired value' ? false : $override;
}, 10, 4);

Override based on a custom condition

This example shows how to override the empty fields behavior based on a custom condition:

add_filter('gform_mailchimp_override_empty_fields', function($override, $form, $entry, $feed) {
    // Add your custom condition here
    $custom_condition = true;
    return $custom_condition ? false : $override;
}, 10, 4);

Place your code snippet in the functions.php file of your active theme.