Enum arguments are serialized as strings when used inside inline fragments

[HawkOnPK]

Package version

graphql-zeus: 7.2.1

Problem

When an enum argument is used on a field selected inside an inline fragment, Zeus serializes the enum value as a quoted string.

GraphQL enums must be serialized without quotes. The generated query is therefore rejected by GraphQL servers.

Minimal schema

type Query {
  items: [Item!]!
}

type Item {
  nested(filter: [NestedFilter!]): [Nested!]!
}

type Nested {
  id: ID!
}

enum NestedFilter {
  ACTIVE
  ARCHIVED
}

Reproduction

import {Zeus, NestedFilter} from './zeus';

const queryWithoutInlineFragment = Zeus('query', {
  items: {
    nested: [
      {filter: [NestedFilter.ACTIVE]},
      {
        id: true
      }
    ]
  }
});

console.log(queryWithoutInlineFragment);

const queryWithInlineFragment = Zeus('query', {
  items: {
    '...on Item': {
      nested: [
        {filter: [NestedFilter.ACTIVE]},
        {
          id: true
        }
      ]
    }
  }
});

console.log(queryWithInlineFragment);

Actual result

Without inline fragment, the enum is serialized correctly:

query {
  items {
    nested(filter: [ACTIVE]) {
      id
    }
  }
}

With inline fragment, the enum is serialized as a string:

query {
  items {
    ...on Item {
      nested(filter: ["ACTIVE"]) {
        id
      }
    }
  }
}

Expected result

The enum should also be serialized without quotes inside inline fragments:

query {
  items {
    ...on Item {
      nested(filter: [ACTIVE]) {
        id
      }
    }
  }
}

Suspected cause

The generated Zeus query builder resolves argument types through an internal string path in InternalArgsBuilt(...) / ResolveFromPath(...).
For the normal case, the argument path can be resolved to something equivalent to:

Item.nested.filter -> NestedFilter -> enum

Inside an inline fragment, the internal path appears to include the inline fragment as if it were a real field:

Query | items | ...on Item | nested | filter

Since ...on Item is not a real schema field, the type lookup fails. Zeus no longer recognizes filter as an enum argument and falls back to normal string serialization.
There already seems to be inline-fragment-specific path handling in PrepareScalarPaths(...), where inline fragments are not added to the scalar response path. Similar handling may be needed for argument path construction in InternalsBuildQuery(...) / InternalArgsBuilt(...).

Related issue

This may be related to #425, which also appears to involve nested argument type resolution, but this case affects enum serialization rather than scalar encoding.

(description generated with ai)