Connections inside of union fragments are not converted from arrays

It seems any Relay connection inside a fragment in a union or interface is ignored by the arrToConnection function since this function ignores typedChildren in the SQL AST.

Example query:

{
  files {
    edges {
      node {
        id
        name
        path
        
        ... on Folder {
          contents {
            edges {
              node {
                id
                name
                path
              }
            }
          }
        }
      }
    }
  }
}

Expected output:

{
  "data": {
    "files": {
      "edges": [
        {
          "node": {
            "id": "Rm9sZGVyOjE=",
            "name": "a folder",
            "path": "/",
            "contents ": {
              "edges": [
                {
                  "node": {
                    "id": "Rm9sZGVyOjI=",
                    "name": "another folder",
                    "path": "/a folder/"
                  }
                }
              ]
            }
          }
        }
      ]
    }
  }
}

Actual output:

{
  "data": {
    "files": {
      "edges": [
        {
          "node": {
            "id": "Rm9sZGVyOjE=",
            "name": "a folder",
            "path": "/",
            "contents ": {
              "edges": null
            }
          }
        }
      ]
    }
  }
}

Using debugging mode I can see that the data is retrieved correctly and initially stored as an array but the sqlAST contains the SQLASTNode information in sqlAST.typedChildren.Folder[] rather than sqlAST.children and so it never processes the array into connection format and the response edges is null instead of an array of nodes.

[meticoeus]

@hugobarreiro Thanks for tackling the unit test part of this fix. I haven’t been able to spend more time on this lately.

[alexbbt]

You can definitely contribute these! Please do in fact