Validation Return Value

[TheoFreundAtHT]

Hi,

when building a checkout validaiton function I noticed the following:
The return value for the function is an array of FunctionErrors, typed as

  /** Returns a message describing the error. */
  localizedMessage: Scalars['String']['input'];
  /** Specifies the path/target for use by the UI. */
  target: Scalars['String']['input'];
};

but when checking the response to [shop-url]/checkouts/internal/graphql/persisted?operationName=Proposal
i found that the errors are defined as such:

"errors": [
    {
        "code": "PAYMENTS_UNACCEPTABLE_PAYMENT_AMOUNT",
        "localizedMessage": "Your order total has changed. Review and try again.",
        "nonLocalizedMessage": "The sum of proposed payments cannot cover the total amount to be paid.",
        "localizedMessageHtml": "Your order total has changed. Review and try again.",
        "target": "$.payment",
        "__typename": "UnprocessableTermViolation"
    },
    {
        "code": "VALIDATION_CUSTOM",
        "localizedMessage": "",
        "nonLocalizedMessage": "custom error message here,
        "localizedMessageHtml": null,
        "target": "$.cart",
        "__typename": "UnprocessableTermViolation"
    },
    {
        "code": "VALIDATION_CUSTOM",
        "localizedMessage": "",
        "nonLocalizedMessage": "custom error message here",
        "localizedMessageHtml": null,
        "target": "$.cart",
        "__typename": "UnprocessableTermViolation"
    }
    ]

Now I have the following questions:

1. Even though I supplied a "localizedMessage" in the server-side validation, I get a "nonLocalizedMessage", why is that?
2. Is it possible to populate the localizedMessageHtml in any way? I would love to be able to include a link in the message.
3. I am very unsure as to why the PAYMENTS_UNACCEPTABLE_PAYMENT_AMOUNT error is appearing.

I am trying to solve for the following:
I need to validate checkout for line items that are missing a certain property. I am doing this via server-side validation to catch Express checkout methods as well as standard payments. As I had implemented with client-side validation at first, I included a link in the error message to point the customer into the right direction.