GraphQL cart error messages

[lenaorobei]

Problem

Now in GraphQL when multiple errors occur with cart there is no way to read all cart messages in order to understand the whole context.

Solution

@XxXgeoXxX proposes to add additional filed to the Cart type magento/graphql-ce#475
Names changed by me but, PR will be adjusted once approved here.

Requested Reviewers

@paliarush

[paliarush]

Please provide a use case when identifier is needed on storefront.

It seems like it should not be exposed to storefront. If so than this CartError type is excessive and its usages can be replaced with String

[XxXgeoXxX]

The main reason to add the identifier is localizing part of process where errors were thrown. It should fetch profit for developers who extend base functionality and implements new features.

[paliarush]

Please explain in proposal why it is not possible to use built-in mechanism for GraphQL errors along with \Magento\Framework\Validation\ValidationException::getErrors

[XxXgeoXxX]

The main reason that resolvers have conditions to prevent the execution of add product to cart and show items in the cart(example app/code/Magento/QuoteGraphQl/Model/Cart/AddProductsToCart.php). That behavior difference with frontend where the customer could see products in cart with messages on frontend but in graphql query he got the error.

[paliarush]

Please explain in the proposal why we should ignore other message types like success, notice, warning

[XxXgeoXxX]

In base PR magento/graphql-ce#475 we expected all kind of messages. Looks like we need rename CartError to CartMessages.

[paliarush]

Suggested change

	text: String
	text: String!

[paliarush]

Suggested change

	identifier: String
	identifier: String!

[lenaorobei]

@paliarush @XxXgeoXxX we have an alternative proposal here magento/graphql-ce#970

It will look like this:

{
  "errors": [
    {
      "message": "First error.",
      "extensions": {
        "category": "graphql"
      },
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ]
    },
    {
      "message": "Second error.",
      "extensions": {
        "category": "graphql"
      },
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ]
    }
  ]
}

Please let me know what do you think.

[lenaorobei]

Closing in favor of magento/graphql-ce#970

[paliarush]

@lenaorobei it looks to me that there is a bug in the native error handling functionality which should be fixed. We should not introduce custom error messages.