REST API: Add variation product type to response

[mattsherman]

Submission Review Guidelines:

• I have followed the WooCommerce Contributing Guidelines and the WordPress Coding Standards.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• I have reviewed my code for security best practices.
• Following the above guidelines will result in quick merges and clear and detailed feedback when appropriate.

Changes proposed in this Pull Request:

This PR address the need to be able to distinguish the product type of a product variation by adding the following two properties property to the product variation REST API responses:

• type -- the product type for the variation
• parent_type -- the product type of the variation's parent

This needs has been identified by third party extension developers when considering how to distinguish product variation types in the context of the new product editor:

• https://developer.woocommerce.com/2023/11/17/getting-to-know-woo-extensibility-in-the-new-product-editor/#comment-20676

Prior to this PR, no type property was returned for product variations, which made it impossible to determine the specific type of variation.

Questions:

• Is there any reason why the type property was not originally included with product variation responses?
  • This seems harmless to add, but I may be missing historical context.
• Is the parent_type property addition necessary?
  • In theory, I see no inherent restriction in WooCommerce that would limit all variations of a variable product to be the exact same type, or a variation of a particular type to always have the same parent type, so this seems like a reasonable addition to help further cover different ways of distinguishing variations.
  • But, it does have a potential performance implication...
• Is the parent_type property addition a performance concern?
  • How can I quantify the performance hit from this?

Update: I removed the parent_type property for now because we do not have an immediate need for it.

How to test the changes in this Pull Request:

1. Add some variable products with variations.

2. Install a plugin such as WooCommerce Subscriptions that adds additional variable/variation types.

3. Using a tool such as Postman, make REST API requests to get variations (REST API doc)

   • REST endpoint for variations: /wp-json/wc/v3/products/<product_id>/variations

4. Verify that the type and parent_type properties property is correct

   • For Variable Product variations, the type is variation
   • For Variable Subscription variations, the type is subscription_variation

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Significance

• Patch
• Minor
• Major

Type

• Fix - Fixes an existing bug
• Add - Adds functionality
• Update - Update existing functionality
• Dev - Development related task
• Tweak - A minor adjustment to the codebase
• Performance - Address performance issues
• Enhancement - Improvement to existing functionality

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[github-actions]

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[github-actions]

Hi @jorgeatorres, @woocommerce/mothra

Apart from reviewing the code changes, please make sure to review the testing instructions as well.

You can follow this guide to find out what good testing instructions should look like:
https://github.com/woocommerce/woocommerce/wiki/Writing-high-quality-testing-instructions

[nathanss]

I've explored a very similar approach locally and it works, I didn't see any regressions and it meets expectations, which is to have a property type which will always be variation for product variations.

[mattsherman]

@woocommerce/proton It would be helpful if somebody on your team could also review this to make sure we aren't overlooking a reason why this wasn't in place originally! Thanks!

[jorgeatorres]

@mattsherman: Thanks for submitting the PR. We also don't know the context on why this wasn't in place originally, but the change looks good to us.

Would you please mind expanding a bit on the testing instructions before merging? I think it'd be best to explicitly indicate the URL that should be used for the REST part of the test (i.e. /wp-json/wc/v3/products/<product_id>/variations) and confirm that for regular variable products you'll get variation but for Subscriptions variable products you should get subscription_variation.

Thanks again!

[mattsherman]

@mattsherman: Thanks for submitting the PR. We also don't know the context on why this wasn't in place originally, but the change looks good to us.

Would you please mind expanding a bit on the testing instructions before merging? I think it'd be best to explicitly indicate the URL that should be used for the REST part of the test (i.e. /wp-json/wc/v3/products/<product_id>/variations) and confirm that for regular variable products you'll get variation but for Subscriptions variable products you should get subscription_variation.

Thanks again!

Thanks for asking for more detailed testing instructions... they were a bit lacking!