fix(product): avoid loading all variants on scalar variant updates

[avonian]

What

Fixes mutation response performance for products with many variants (400+).

The problem

Multiple product sub-resource mutation routes (variant CRUD, option CRUD) use retrieveProductQueryConfig for the post-mutation refetchEntity call. This config includes *variants, *variants.prices, variants.prices.price_rules.*, *variants.options — loading ALL variants with all their prices, rules, and options after a single sub-resource change.

Profiling results on a product with 414 variants:

Operation	Time
updateProductVariantsWorkflow	3.5s
refetchEntity with full product config	11min 51s
Total POST response	11min 54s

The admin dashboard already fetches variants separately via GET requests (using fields=-variants). The mutation responses don't need to include all variant data.

The fix

1. Lean product query config for sub-resource mutations

Added retrieveProductWithoutVariantsQueryConfig that filters out *variants and variants.* fields. Applied to these middleware configs:

• POST /admin/products/:id/variants (create variant)
• POST /admin/products/:id/variants/:variant_id (update variant)
• DELETE /admin/products/:id/variants/:variant_id (delete variant)
• POST /admin/products/:id/options (create option)
• POST /admin/products/:id/options/:option_id (update option)
• DELETE /admin/products/:id/options/:option_id (delete option)

2. Conditional allVariants loading in updateVariants_

updateVariants_() unconditionally loads all sibling variants with options for the checkIfVariantWithOptionsAlreadyExists validation, even when options aren't being updated. Moved the query inside the conditional so it only runs when options are present in the update payload.

Files changed

• packages/medusa/src/api/admin/products/query-config.ts — add lean product config
• packages/medusa/src/api/admin/products/middlewares.ts — use lean config for 6 sub-resource routes
• packages/modules/product/src/services/product-module-service.ts — conditional allVariants loading

Impact

• Sub-resource mutations no longer refetch all variants with prices
• No behavior change for product-level GET/POST/DELETE routes
• No behavior change for variant creation or option-changing updates in the service layer
• Follow-up to fix(product): Update performance issue #14150 which fixed product update performance

Fixes #14727

[changeset-bot]

⚠️ No Changeset found

Latest commit: da6b1f0

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel]

@avonian is attempting to deploy a commit to the medusajs Team on Vercel.

A member of the Team first needs to authorize it.