Querying `blocks` field of a `StructBlock` in a `StreamField` breaks query

[tbrlpld]

Hi,

I just ran into an error when trying to query the blocks field of a StructBlock in a StreamField.

My BlogPage Wagtail model contains a StreamField like this:

class BlogPage(HeadlessPreviewMixin, Page):
    ...
    freeformbody = StreamField(
        [
            ...
            ('person', blocks.StructBlock([
                ('first_name', blocks.CharBlock()),
                ('last_name', blocks.CharBlock()),
                ('photo', ImageChooserBlock(required=False)),
                ('biography', blocks.TextBlock()),
            ], icon='user')),
            ...
        ],
        blank=True,
    )

    graphql_fields = [
        ...
        gpm.GraphQLStreamfield('freeformbody'),
        ...
    ]

A query for the StructBlock without the blocks field will work fine and I get the expected response.

query ($slug: String) {
  wagtail {
    page(slug: $slug) {
      ... on BlogPage {
        freeformbody {
          ... on StructBlock {
            id
            rawValue
          }
        }
      }
    }
  }
}

But when I add the blocks field

query ($slug: String) {
  wagtail {
    page(slug: $slug) {
      ... on BlogPage {
        freeformbody {
          ... on StructBlock {
            id
            rawValue
            blocks {
              id
            }
          }
        }
      }
    }
  }
}

then I get the following error:

{
  "errors": [
    {
      "message": "int() argument must be a string, a bytes-like object or a number, not 'Image'",
      "locations": [
        {
          "line": 9,
          "column": 13
        }
      ],
      "path": [
        "wagtail",
        "page",
        "freeformbody",
        21,
        "blocks"
      ],
      "stack": [
        "Error: int() argument must be a string, a bytes-like object or a number, not 'Image'",
        "    at defaultMergedResolver (<...>node_modules/graphql-tools/dist/stitching/defaultMergedResolver.js:15:36)",
        "    at wrappedTracingResolver (<...>node_modules/gatsby/dist/schema/resolvers.js:412:14)",
        "    at wrappedTracingResolver (<...>node_modules/gatsby/dist/schema/resolvers.js:412:14)",
        "    at wrappedTracingResolver (<...>node_modules/gatsby/dist/schema/resolvers.js:412:14)",
        "    at wrappedTracingResolver (<...>node_modules/gatsby/dist/schema/resolvers.js:412:14)",
        "    at resolveFieldValueOrError (<...>node_modules/graphql/execution/execute.js:467:18)",
        "    at resolveField (<...>node_modules/graphql/execution/execute.js:434:16)",
        "    at executeFields (<...>node_modules/graphql/execution/execute.js:275:18)",
        "    at collectAndExecuteSubfields (<...>node_modules/graphql/execution/execute.js:713:10)",
        "    at completeObjectValue (<...>node_modules/graphql/execution/execute.js:703:10)",
        "    at completeAbstractValue (<...>node_modules/graphql/execution/execute.js:660:10)",
        "    at completeValue (<...>node_modules/graphql/execution/execute.js:585:12)",
        "    at completeValueCatchingError (<...>node_modules/graphql/execution/execute.js:495:19)",
        "    at <...>node_modules/graphql/execution/execute.js:618:25",
        "    at Array.forEach (<anonymous>)",
        "    at forEach (<...>node_modules/iterall/index.js:83:25)"
      ]
    }
  ],
  "data": {
    ...
  }
}

It seems like the issue is related to the handling of the ImageChooserBlock that is on field in the StructBlock.

Update: I just confirmed it. When I remove the ImageChooserBlock from the StructBlock definition, then I can query the blocks field successfully.

Update: Just added the field back in and it worked as long as no image was defined for the field in the backend. Once an image is selected, then it breaks.

[tbrlpld]

Sorry, just realized this is already coming from the backend. I'll open the issue in the Grapple repo and close this one.

[tbrlpld]

Guess this is related to https://github.com/GrappleGQL/wagtail-grapple/issues/48 and https://github.com/GrappleGQL/wagtail-grapple/pull/54