Add helper method to get WooCommerce object meta value

[nmolham-godaddy]

Summary

Adds SV_WC_Helper::getWooCommerceObjectMetaValue that gets value of a meta key from WooCommerce object based on its data type.

Story: MWC-17547

QA

• Code review
• Checks pass

Before merge

• I have confirmed these changes in each supported minor WooCommerce version

[agibson-godaddy]

Reading through the Woo source code, I understand what you have here will absolutely work for any WC class that extends WC_Data (such as products).

Just wondering if it's at all weird/risky to use the OrderUtil class anyway? That class is described as a utility class for orders, and it does work with products anyway, but do you think there's a risk of that ever changing so that it is orders only?

[nmolham-godaddy]

Good question, as far as I can tell, the same OrderUtil class is used in many places in WC codebase to get all sort of meta data for objects despite being orders or not! I know it is weird and sounds risky, but if you look into OrderUtil::get_post_or_object_meta source code, it doesn't case if the passed object is an order or not, it just loos for the WC_Data or WP_Post

I can't find an equivalent to is within WC codebase for products or any other WC_Data/WP_Post based objects

[ajaynes-godaddy]

Knowing it's considered to be an internal utility class, it might not be the worst idea to abstract the source of get_post_or_object_meta() to our own trait or helper.

	public function get_post_or_object_meta( ?WP_Post $post, ?\WC_Data $data, string $key, bool $single ) {
		if ( isset( $data ) ) {
			if ( method_exists( $data, "get$key" ) ) {
				return $data->{"get$key"}();
			}
			return $data->get_meta( $key, $single );
		} else {
			return isset( $post->ID ) ? get_post_meta( $post->ID, $key, $single ) : false;
		}
	}

[nmolham-godaddy]

At first I thought about doing so, but I remembered how many time WC change stuff internally that causes compatibility issues. So, the idea here is to use their implementation with fallback with our own implementation.

Make sense?

[ajaynes-godaddy]

I think I'm going to try just adding it as a second method to the helper, see how annoying the tests are to write.

[ajaynes-godaddy]

Added the compat method in 9f45812 and 287c7be

Feel free to revert or adjust as needed.

[nmolham-godaddy]

That looks good to me, how about you @agibson-godaddy, what do you think?