Merchant request: enable GTIN from 3pd plugin

[sophiegyo]

User story

Reference 7873440-zen

• The merchant uses a 3pd plugin to insert GTIN: https://wordpress.org/plugins/woo-add-gtin/
• They are aware this plugin has not been updated in a while
• They would like Google Listings & Ads to be able to pick up the GTIN from this plugin
• They do not wish to use the prescribed method in the Google Listings & Ads docs:
  https://woo.com/document/google-listings-and-ads/#global-attribute-mapping

I let them know I'd pass the request on but did not guarantee it would be implemented.

Is your feature request related to a problem?

• They find the GLA prescribed method isn't convenient for managing individual GTINs for each product

How to reproduce the problem

1. Site with WooCommerce, Google Listings & Ads, and the above 3pd plugin
2. Add GTIN using the 3pd plugin
3. Try to use attribute mapping in GLA
4. GTIN field from 3pd plugin is not detected

Describe the solution you'd like

The merchant would like GLA to be able to use the GTIN as detailed here:
https://wordpress.org/support/topic/where-the-woocommerce-gtin-value-is-stored/

Describe alternatives you've considered

• I did suggest testing out the GTIN method from the GLA docs.
• I also let the merchant know about the Yoast option:
  https://woo.com/document/google-listings-and-ads/attribute-mapping-use-cases/#section-4

Technical

• I'm aware this is a 3pd plugin with their own custom implementation of how they add the GTIN and that we can't account for every 3pd plugin out there.

Out of bounds/rabbit holes

See above!

[eason9487]

Looks like their could try this filter to set the GTIN.

For example:

add_filter(
	'woocommerce_gla_product_attribute_value_gtin',
	function ( $value, WC_Product $product ) {
		$gtin = 'Get the GTIN from another plugin';
		return $gtin;
	},
	10,
	2
);