Force Default Value

<?php
/**
 * Gravity Wiz // Gravity Forms // Force Default Value
 * https://gravitywiz.com/
 *
 * Instruction Video: https://www.loom.com/share/ce1cee94063348f09d57b404d26c4e8a
 *
 * Force the default value to be captured for fields hidden by conditional logic. Also reprocesses default values that
 * contain merge tags not available for prepopulation.
 *
 * The latter functionality is useful when wanting to combine data into specifically formatted values. For example, you
 * can use "{entry:gpaa_lat_1},{entry:gpaa_lng_1}" to format the latitude and longitude captured by GP Address Autocomplete
 * into a comma-delimited pair.
 *
 * Currently, this will only work with single input fields.
 *
 * Plugin Name:  Gravity Forms - Force Default Value
 * Plugin URI:   https://gravitywiz.com/
 * Description:  Force the default value to be captured for fields hidden by conditional logic.
 * Author:       Gravity Wiz
 * Version:      1.3
 * Author URI:   https://gravitywiz.com/
 */
class GW_Force_Default_Value {

	public function __construct( $args = array() ) {

		// set our default arguments, parse against the provided arguments, and store for use throughout the class
		$this->_args = wp_parse_args( $args, array(
			'form_id'   => false,
			'field_ids' => array(),
		) );

		// do version check in the init to make sure if GF is going to be loaded, it is already loaded
		add_action( 'init', array( $this, 'init' ) );

	}

	public function init() {

		// make sure we're running the required minimum version of Gravity Forms
		if ( ! property_exists( 'GFCommon', 'version' ) || ! version_compare( GFCommon::$version, '1.9', '>=' ) ) {
			return;
		}

		// carry on
		add_filter( 'gform_entry_post_save', array( $this, 'add_default_values_to_entry' ), 10, 2 );
		add_filter( 'gform_replace_merge_tags', array( $this, 'replace_unreplaced_merge_tags' ) );

	}

	public function add_default_values_to_entry( $entry, $form ) {

		if ( ! $this->is_applicable_form( $form ) ) {
			return $entry;
		}

		$requires_update = false;

		/** @var GF_Field $field */
		foreach ( $form['fields'] as $field ) {

			if ( ! $this->is_applicable_field( $field ) ) {
				continue;
			}

			$entry_value = rgar( $entry, $field->id );
			$is_hidden   = GFFormsModel::is_field_hidden( $form, $field, array(), $entry );

			// Get default value if field is hidden.
			if ( $is_hidden || ( empty( $entry_value ) && ! GFFormDisplay::is_field_validation_supported( $field ) ) ) {
				$value = $field->get_value_default_if_empty( $field->get_value_submission( array(), false ) );
			} else {
				$value = $entry_value;
			}

			if ( rgblank( $value ) ) {
				continue;
			}

			$value = GFCommon::replace_variables( $value, $form, $entry );

			if ( $value != $entry_value ) {
				$requires_update     = true;
				$entry[ $field->id ] = $value;
			}
		}

		if ( $requires_update ) {
			GFAPI::update_entry( $entry );
		}

		return $entry;
	}

	/**
	 * If default value *is* a merge tag (or multiple merge tags), and these merge tags still exist after prepopulation
	 * merge tags have been replaced, assume that this is a merge tag that should be replaced on submission and clear
	 * it from the default value so that the user does not see the merge tag if the field is visible.
	 *
	 * @param $text
	 *
	 * @return mixed|string
	 */
	public function replace_unreplaced_merge_tags( $text ) {
		if ( isset( $_POST['gform_submit'] ) ) {
			return $text;
		}
		$chars = str_split( trim( $text ) );
		if ( $chars[0] === '{' && $chars[ count( $chars ) - 1 ] === '}' ) {
			$text = '';
		}
		return $text;
	}

	function is_applicable_form( $form ) {

		$form_id = isset( $form['id'] ) ? $form['id'] : $form;

		return empty( $this->_args['form_id'] ) || $form_id == $this->_args['form_id'];
	}

	function is_applicable_field( $field ) {
		return empty( $this->_args['field_ids'] ) || in_array( $field->id, $this->_args['field_ids'] );
	}

}

# Configuration

new GW_Force_Default_Value( array(
	'form_id'   => 123,
	'field_ids' => array( 4, 5 ),
) );