Query parsing error when no documents with a Link field value

[patts (Andy Pattenden)]

I have the following custom types (simplified for this post):

Blog Category (blog_category):

{
  "Main" : {
    "uid" : {
      "type" : "UID",
      "config" : {
        "label" : "Page Slug",
        "placeholder" : "Unique identifier for category URL"
      }
    },
    "title" : {
      "type" : "Text",
      "config" : {
        "label" : "title"
      }
    },
  },
}

Blog Subcategory (blog_subcategory):

{
  "Main" : {
    "uid" : {
      "type" : "UID",
      "config" : {
        "label" : "Page Slug",
        "placeholder" : "Unique identifier for subcategory URL"
      }
    },
    "title" : {
      "type" : "Text",
      "config" : {
        "label" : "title"
      }
    },
    "category" : {
      "type" : "Link",
      "config" : {
        "select" : "document",
        "customtypes" : [ "blog_category" ],
        "label" : "Category"
      }
    }
  }
}

I am fetching all blog_subcategory documents which have a category value using the following query:

const data = client.query(
  [
    Prismic.Predicates.at('document.type', 'blog_subcategory'),
    Prismic.Predicates.has('my.blog_subcategory.category'),
  ],
  opts
)

which results in this query string:

q=%5B%5Bat(document.type%2C+%22blog_subcategory%22)%5D%5Bhas(my.blog_subcategory.category)%5D%5D

If I have no blog_subcategory documents or no blog_subcategory documents with a category value set, I would expect the response from the request above to return 0 documents. Instead it returns a 400 response with the following error:

{
  "message": "[function has(..)] unexpected field 'my.blog_subcategory.category' on line:1 col:46 in query '[[at(document.type, \"blog_subcategory\")][has(my.blog_subcategory.category)]]'\n[[at(document.type, \"blog_subcategory\")][has(my.blog_subcategory.category)]]\n                                              ^\n","type":"parsing-error","line":1,"column":46,"id":0,"location":"query"
}

As soon as I add at least one blog_subcategory document which has a category value, the query returns the documents as expected.

I have also tested the above using the API Browser which results in the same behaviour.

Is the error response above expected behaviour?

[Levi (Levi Gable)]

Hi @patts. The 400 response you’ve seen is the expected behavior. As you’ve discovered, the way to fix it is to publish at least one document of that type.

I completely agree that it makes more sense for the API to return 0 responses, though. So I will let the @features-team know about this and we will add this to our feature request tracker as a possible improvement for the future. We don’t have any plans to work on this right now, but we will let you know here if that changes at any point.