Error: "[couponValueType] This value should not be blank" When Using WooCommerce Subscriptions Discount Types

[imhossen1]

Describe the bug:

When attempting to create a coupon in WooCommerce with the discount type set to "Recurring Product % Discount" and enabling the "Show coupon on Google" option, an error message appears: [couponValueType] This value should not be blank. This error prevents the coupon from being displayed on Google. In contrast, using the standard "Percentage Discount" type allows the coupon to sync with Google without issues.

Issue occurs: when we set Recurring Product % Discount.

Works fine with Percentage Discount

Steps to reproduce:

1. Navigate to the WooCommerce dashboard.
2. Go to Marketing > Coupons.
3. Click on Add Coupon.
4. In the Discount type dropdown, select Recurring Product % Discount.
5. Set the Coupon amount.
6. Enable the Show coupon on Google option.
7. Click Publish to save the coupon.
8. Observe the error: [couponValueType] This value should not be blank.

Expected behavior:

The coupon should be synced with Google successfully, allowing it to be applied to subscription products with a recurring percentage discount and working on Google as intended.

Actual behavior:

Upon clicking Publish, an error message is displayed: [couponValueType] This value should not be blank, preventing the sync with Google.

Additional details:

• It is reproducible across various environments, regardless of WooCommerce, WordPress, and WooCommerce Subscriptions plugin versions.
• The Recurring Product % Discount may not align with Google's discount schema, which may only expect standard types like "Percentage" or "Fixed Discount," indicating a possible oversight in the plugin's handling of this discount type.
• Ref: 9056434-zd-a8c