Checkout validation function query input variables

Technical Q&A

Topic summary

Main issue: Passing a shop metafield as a query input variable to a Shopify Checkout Validation function fails. The variable ($protectedCollectionsIds) intended for product inAnyCollection(ids: $protectedCollectionsIds) remains null, causing inAnyCollection to return False.

Setup: The app sets a shop-level metafield via metafieldsSet (ownerId = Shop GID, type json) and configures the function with [extensions.input.variables] using the same namespace/key. The metafield is readable in the query under shop, but the input variable itself isn’t injected.

Observed behavior: If a default value is hardcoded in the GraphQL query (e.g., [“gid://shopify/Collection/477600842047”]), inAnyCollection returns True as expected. The same variable approach works in Discount Functions.

Update/clarification: A response cites a Shopify community thread indicating input variables are not yet supported for Cart/Checkout Validation functions.

Outcome: This is a current platform limitation, not a misconfiguration. No full workaround beyond hardcoding defaults or avoiding variable-based injection in Checkout Validation. Status: unresolved/awaiting platform support.

Summarized with AI on December 27. AI used: gpt-5.
1

Hello, i’m trying to use checkout validation function with query input variables as it described in the docs
https://shopify.dev/docs/apps/functions/input-output/variables-queries

First of all, there is absolutely unclear information about how to find ownerID. But as i’ve reed on the community forum - Shop is the owner.
But it doesn’t work, i see metafields in the shop, but inAnyCollection filter still return False, when True is expected

Here is a quick sample for it
Query Input (run.graphql)
query RunInput($protectedCollectionsIds: [ID!]) {
cart {
lines {
merchandise{
__typename
… on ProductVariant {
id
product {
id
inAnyCollection(ids: $protectedCollectionsIds)
}
}
}
}
}
shop{
protectedCollectionsIds: metafield(namespace: “$app:nifty-bridge”, key: “protectedCollectionsIds”){
value
}
}
}

Function config(shopify.extension.toml)

[extensions.input.variables]
namespace = “$app:nifty-bridge”
key = “protectedCollectionsIds”

MetaieldsSet input
{
key: “protectedCollectionsIds”,
namespace: $app:${METAFIELDS_NAMESPACE},
ownerId: shopifyShopGId,
type: “json”,
value: JSON.stringify({ protectedCollectionsIds }),
}

Output
i can receive protectedCollectionsIds in the shop metafields

shop{
“protectedCollectionsIds”: { “value”: “{"protectedCollectionsIds":["gid://shopify/Collection/477600842047"]}” }
}

But inAnyCollection in input still False for the product

If i will set default value for $protectedCollectionsIds from metafields
query RunInput($protectedCollectionsIds: [ID!]=[“gid://shopify/Collection/477600842047”])

inAnyCollection will be True, as expected

Can someone help me to figure out how to work with it?
I’ve tried with discount functions and it works as expected.

2

Well apparently it’s not yet possible to use input variables in the checkout validation, see here.
I have a similar issue where I’m setting a metafieldsSet with shop id and a JSON but my variable input is marked as null where its working well with discount.