Ensure coupon brand restrictions are uploaded to Google Merchant Center.

[ianlin]

Changes proposed in this Pull Request:

Closes #2693.

Since WooCommerce 9.4, WooCommerce Brands is now part of the WooCommerce core, the merchant can add brand restrictions when editing coupons, but G4W plugin does not upload the corresponding coupon brand restrictions to Google Merchant Center.

This PR adds coupon restrictions for brands when generating the coupon (promotions) payload for updating to Google Merchant Center.

Note that WC_Coupon class does not have a method to get the brand restrictions like other restrictions do. This PR uses get_post_meta() to get the brands from a coupon, then uses get_objects_in_term() to get a list of product IDs from that brand.

Refer to the following tables to better understand the data:

• wp_postmeta
  • Store the brands for coupons, queried byget_post_meta()
  • Meta keys: product_brands and exclude_product_brands
• wp_terms
  • Where the brand ID, brand name, and brand slug are stored
• wp_term_taxonomy
  • Store the taxonomy for the brand (product_brand)
• wp_term_relationships
  • Store the mapping of products and brand. Queried by get_objects_in_term()
  • Should specify the brand taxonomy product_brand in get_objects_in_term()

Updated 28th Nov

For querying brands from a coupon from post_meta, I found in class-wc-brands-brand-settings-manager.php I can use it like:

\WC_Brands_Brand_Settings_Manager::set_brand_settings_on_coupon( $coupon );
$brand_settings = \WC_Brands_Brand_Settings_Manager::get_brand_settings_on_coupon( $coupon );

However, since we do not expect all merchants update to latest WooCommerce, we also need to ensure backward compatibility for those who still use WC Brands plugin. The code above was available since WC Brands plugin version 1.6.65, so I lean towards to still querying post_meta manually as it's safest for all version and in core.

Screenshots:

Detailed test instructions:

1. Build the project using this PR, and ensure WooCommerce >= 9.4 is installed on your site
2. Enable Brands feature by updating two options wc_feature_woocommerce_brands_enabled and woocommerce_remote_variant_assignment

   wp option update wc_feature_woocommerce_brands_enabled 'yes'
   wp option update woocommerce_remote_variant_assignment 2

3. Create some brands from Products > Brands, e.g.
   
4. Add some products to each of the brand that just created, e.g.

Screen.Recording.2024-11-27.at.15.07.31.mov

5. Create a coupon, add brand restrictions to it
   • Make sure your store country supports coupons, e.g. US, GB.
   • Make sure to choose Show coupon on Google in Channel visibility
   • Note that the inclusion and exclusion cannot be set at the same time, otherwise Google API will respond 400 bad request. It also applies to existing restrictions like products or product categories.
   • 
6. Save the coupon, go to WooCommerce > Status > Scheduled Actions, search for the job gla/jobs/update_coupon/process_item, run it manually if it is still pending to save time
7. Wait for a while, go to Google Merchant Center, click Promotions from the left menu.
8. Click on the coupon (promotion) you just uploaded, then click Next. Ensure that the filters display the product IDs associated with the brand set as a restriction.

Screen.Recording.2024-11-27.at.15.24.52.mov

9. Play around the existing restrictions, make sure they are still working
10. Disable the Brands in core feature (see step 2), make sure the PR won't break it
11. Using WooCommerce beta tester to downgrade WC to 9.2, and install WC Brands plugin, make sure the PR still works.

Additional details:

Changelog entry

Fix - Ensure coupon brand restrictions are uploaded to Google Merchant Center.

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 2 lines in your changes missing coverage. Please review.

Project coverage is 65.8%. Comparing base (16ff73f) to head (1e73c90).
Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/Coupon/WCCouponAdapter.php	92.3%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             develop   #2697     +/-   ##
===========================================
+ Coverage       65.1%   65.8%   +0.8%     
- Complexity      4658    4665      +7     
===========================================
  Files            812     477    -335     
  Lines          24578   19456   -5122     
  Branches        1254       0   -1254     
===========================================
- Hits           15990   12807   -3183     
+ Misses          8416    6649   -1767     
+ Partials         172       0    -172     

Flag	Coverage Δ
js-unit-tests	?
php-unit-tests	65.8% <92.3%> (+<0.1%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/Coupon/WCCouponAdapter.php	80.7% <92.3%> (+1.4%)	⬆️

... and 335 files with indirect coverage changes

[ianlin]

Thanks for the good catch @eason9487. I've updated the PR and it's ready for another round.

[eason9487]

Thanks for the work. Tested that the brand restrictions of coupons can be converted to product IDs and then synced to Google Merchant Center.

However, just noticed there may be another concern. If a product is later created/updated to attach or detach a brand having associations with coupon restrictions, the brand restrictions (converted to associated product IDs) of those coupons won't be synced.

[eason9487]

Suggest adding a compatibility code comment to make it easier to search for compatibility codes in the future.

// compatibility-code "WC < 9.4" -- additional inline description