Adds warning if private properties are accessed outside its class.

[krutidugade]

Changes proposed in this Pull Request:

We defined some private properties to eliminate dynamic property warnings in #2606. In the recent dev call, the team discussed and decided to display a warning if the private properties are accessed outside its class. This PR displays the warning with help of __get and _doing_it_wrong functions.

Related to #2606.

• Do the changed files pass phpcs checks? Please remove phpcs:ignore comments in changed files and fix any issues, or delete if not practical.

Detailed test instructions:

1. Checkout this branch
2. Set WP_DEBUG and WP_DEBUG_LOG to true
3. Access private properties by adding the following block of code under admin_notices() function in facebook-for-woocommerce.php file

$wcprod = new WC_Product();
$accessprivate = new WC_Facebook_Product($wcprod->get_id());
print_r('Hello1');
print_r($accessprivate->fb_description);
print_r($accessprivate->gallery_urls);
print_r($accessprivate->fb_use_parent_image);
print_r($accessprivate->main_description);
print_r($accessprivate->sync_short_description); 
print_r('Hello2');
$fbcom = new WC_Facebookcommerce();
print_r($fbcom->configuration_detection);
print_r($fbcom->fb_categories);
print_r('Hello3');
$integ = new WC_Facebookcommerce_Integration($fbcom);
print_r($integ->events_tracker);
print_r($integ->messenger_chat);
print_r($integ->background_processor);
print_r('Hello4');
print_r((new WooCommerce\Facebook\Admin)->product_sets);
print_r('Hello5');
print_r((new WooCommerce\Facebook\ProductSync\ProductValidator($integ, $wcprod))->facebook_product);
print_r('Hello6');
print_r((new WC_Facebookcommerce_Background_Process($integ))->commerce);
print_r('Hello7');
$enh = new WooCommerce\Facebook\Admin\Enhanced_Catalog_Attribute_Fields("Page");
print_r($enh->page_type);
print_r($enh->term);
print_r($enh->product);
print_r($enh->category_handler);
print_r('Hello8');
$settings = [
	'fb_page_id' => 'abc123',
	'facebook_jssdk_version' => '1.2.3',
];
$messen = new WC_Facebookcommerce_MessengerChat($settings);
print_r($messen->page_id);
print_r($messen->jssdk_version);

5. Verify you see the PHP notices in debug.log and in header of admin page.

[17-Aug-2023 14:49:40 UTC] PHP Notice:  Function __get was called <strong>incorrectly</strong>. The fb_description property is private and should not be accessed outside its class. Please see <a href="https://wordpress.org/documentation/article/debugging-in-wordpress/">Debugging in WordPress</a> for more information. (This message was added in version x.x.x.) in /var/www/html/wp-includes/functions.php on line 5905
[17-Aug-2023 14:49:40 UTC] PHP Notice:  Function __get was called <strong>incorrectly</strong>. The gallery_urls property is private and should not be accessed outside its class. Please see <a href="https://wordpress.org/documentation/article/debugging-in-wordpress/">Debugging in WordPress</a> for more information. (This message was added in version x.x.x.) in /var/www/html/wp-includes/functions.php on line 5905

Changelog entry

Tweak - Displays warnings on accessing private/protected properties incorrectly.

[ibndawood]

Thank you, @krutidugade, for the changes. They look good to me. I've added small nitpicks but they are not a blocker.

[rawdreeg]

Shouldn't we add a getter and fix the warning in our own code base? That can be another PR.

[krutidugade]

Shouldn't we add a getter and fix the warning in our own code base? That can be another PR.

I agree with you. There is some room for improvement with the notice. As you suggested, we can look into it in a different PR. Currently, we'll merge this PR to proceed with the release.