[4.x]: GraphQL is missing the siblingOf() argument in StructureElementArguments

[denisyilmaz]

What happened?

Description

We need to query for siblings withing a structure. Currently, there is no way to get all siblings of an entry, only the single next and previous entry.
I checked https://github.com/craftcms/cms/blob/4.4/src/gql/base/StructureElementArguments.php and saw that the argument is missing in this file.

Steps to reproduce

1. Open GraphiQL
2. Query for an entry withing a structure:

query GetPage($id: QueryArgument, $entryId: Int, $level: Int) {
  entry(id: [$id]) {
    title
    ancestors(ancestorOf: $entryId, ancestorDist: 1) {
      title
    }
    descendants(descendantOf: $entryId, descendantDist: 1) {
      title
    }
  }
  # this is only returning the prev sibling, not all previous siblings
  prevSiblings: entries(prevSiblingOf: $entryId, level: $level) {
    title
  }
  # this is only returning the next sibling, not all next siblings
  nextSiblings: entries(nextSiblingOf: $entryId, level: $level) {
    title
  }
  # not working because 'Unknown argument \"siblingOf\" on field \"entries\" of type \"Query\".'
  allSiblings: entries(siblingOf: $entryId) {
    title
  }
}

Expected behavior

Should return an array of all siblings of that entry within its structure except itself

    "entry": {
      "title": "Page 2"
    },
    "prevSiblings": [      {
        "title": "Page 1"
      }
    ],
    "nextSiblings": [
      {
        "title": "Page 3"
      }
    ],
    "allSiblings": [
      {
        "title": "Page 1"
      }, 
      {
        "title": "Page 3"
      },
      {
        "title": "Page 4"
      }
    ]

Actual behavior

{
  "errors": [
    {
      "message": "Unknown argument \"siblingOf\" on field \"entries\" of type \"Query\".",
      "extensions": {
        "category": "graphql"
      },
      "locations": [
        {
          "line": 24,
          "column": 27
        }
      ]
    }
  ]
}

Craft CMS version

4.3.4

PHP version

8.1

Operating system and version

No response

Database type and version

No response

Image driver and version

No response

Installed plugins and versions

[denisyilmaz]

It's also missing for Craft CMS 3

[brandonkelly]

Converted to a discussion since this is a request for new functionality. There are several known limitations with GraphQL compared to normal element queries, and this sounds like one of them. We can consider adding it down the road though.

[denisyilmaz]

Alright, I searched for workaround and found something that I can use in my case:

{
  entries {
    title
    parent {
      descendants {
        title
      }
    }
    descendants {
      title
    }
  }
}

… this gives me all related entries including the entry queries (which I can easily exclude in the frontend).

I don't understand why siblingsOf() wouldn't work in graphQL? Isn't the SQL query same complexity than the descendantsOf/ancestorsOf arguments?

[denisyilmaz]

I found a possible bug:

{
  entry(id:6871) {
    title
    id
    parent {
      title
      descendants {
        title
      }
      before: descendants(positionedBefore: 6871) {
        title
      }
      after: descendants(positionedAfter: 6871) {
        title
      }
    }
    descendants(descendantDist: 1) {
      title
    }
  }
}

expected result:

{
  "data": {
    "entry": {
      "title": "Page 2",
      "id": "6871",
      "parent": {
        "title": "Parent Page",
        "descendants": [
          {
            "title": "Page 1"
          },
          {
            "title": "Page 2"
          },
          {
            "title": "Page 3"
          },
        ],
        "before": [
          {
            "title": "Page 1"
          }
        ],
        "after": [
          {
            "title": "Page 3"
          },
        ]
      },
      "descendants": []
    }
  }
}

actual result:

{
  "data": {
    "entry": {
      "title": "Page 2",
      "id": "6871",
      "parent": {
        "title": "Parent Page",
        "descendants": [
          {
            "title": "Page 3"
          },
        ],
        "before": [
          {
            "title": "Page 3"
          },
        ],
        "after": [
          {
            "title": "Page 3"
          },
        ]
      },
      "descendants": []
    }
  }
}

it seems only the third reference to descendants gets queried and all three fields get that result.

Querying each one of the three descendants on its own i get the expected result.

[brianjhanson]

Looks like it! I'm guessing you're running into the same core issue as #12410, you can follow along over there for updates.

[denisyilmaz]

thanks, adding the mentioned workaround with …

Event::on(
    ElementQueryConditionBuilder::class,
    ElementQueryConditionBuilder::EVENT_REGISTER_GQL_EAGERLOADABLE_FIELDS,
    function(RegisterGqlEagerLoadableFields $event) {
        $event->fieldList['descendants'] = [BaseRelationField::class, 'canBeAliased' => true];
    }
);

… worked here as well.

[denisyilmaz]

Ok, it gets weirder. When querying the descendants with fixed fields and the workaround mentioned by @brianjhanson it works fine:

{
  entry(id: ["6871"]) {
    title
    parent {
      title
      prevSiblings: descendants(positionedBefore: 6871) {
        title
      }
      nextSiblings: descendants(positionedAfter: 6871) {
        title
      }
    }
    children {
      title
    }
  }
}

… but if I create a EntryInterface fragment like this:

fragment Tab on EntryInterface {
  title
}

{
  entry(id: ["6871"]) {
    title
    parent {
      ...Tab
      prevSiblings: descendants(positionedBefore: 6871) {
        ...Tab
      }
      nextSiblings: descendants(positionedAfter: 6871) {
        ...Tab
      }
    }
    children {
      ...Tab
    }
  }
}

… the result will be again a full list of entries for each aliased descendants field.
Adding a fragment for the entry type specifically its working though. Only EntryInterface is the problem here.