Suddenly weird error on page save?

Archive
1

So I was working on a custom page blueprint and all of a sudden I got this error.

Error

I thaught that I made a mistake so I checked it by using a example blueprint from the documentation.

title: Gallery

form:
  fields:
    tabs:
      type: tabs
      active: 1

      fields:
        referentie:
          type: tab
          title: Referenties

          fields: 
            header.an_example_text_field:
              type: text
              label: Add a number
              default: 5
              validate:
                required: true
                type: int

            header.an_example_select_box:
              type: select
              label: Select one of the following
              default: one
              options:
                one: One
                two: Two
                three: Three

            route:
              type: select
              label: PLUGIN_ADMIN.PARENT
              classes: fancy
              '@data-options': '\Grav\Common\Page\Pages::parents'
              '@data-default': '\Grav\Plugin\admin::route'
              options:
                '/': PLUGIN_ADMIN.DEFAULT_OPTION_ROOT

I saved it and everything was fine. But when I removed the ‘route’ part

title: Gallery

form:
  fields:
    tabs:
      type: tabs
      active: 1

      fields:
        referentie:
          type: tab
          title: Referenties

          fields:
            header.an_example_text_field:
              type: text
              label: Add a number
              default: 5
              validate:
                required: true
                type: int

            header.an_example_select_box:
              type: select
              label: Select one of the following
              default: one
              options:
                one: One
                two: Two
                three: Three

The error came back?

This was my original blueprint file that I’ve writen by myself.

title: Referenties

form:
    fields:
        tabs:
            type: tabs
            active: 1
            fields:
                referenties:
                    type: tab
                    title: Referenties
                    fields:
                        header.referenties:
                            type: list
                            name: Referenties
                            style: horizontal
                            fields:
                                .images:
                                    type: file
                                    label: Plaats hier je fotos
                                    destination: 'self@'
                                    multiple: true

Whats wrong?

2

Extend your blueprint from default as it contains some base attributes needed: https://github.com/getgrav/grav-theme-antimatter/blob/develop/blueprints/blog.yaml#L2-L4