Validate group ids for existance

[pinussilvestrus]

What should we do?

The validator should fail if a property defines a group that is not defined in the upper groups array.

The following template should me markets as invalid

{
  'name': 'Grouping',
  'id': 'example.com.missingGroupId',
  'appliesTo': [
    'bpmn:ServiceTask'
  ],
  'properties': [
    {
      'label': 'input 1',
      'type': 'String',
      'group': 'two',
      'binding': {
        'type': 'camunda:inputParameter',
        'name': 'input1'
      }
    }
  ],
  'groups': [
    {
      'id': 'one',
      'label': 'Group one'
    }
  ]
}

Why should we do it?

Make sure we don't use non-existing groups.

[pinussilvestrus]

That might be possible via if-then rule, although it seems to be hard to dynamically test values against a parent array property. Sketch via https://github.com/camunda/element-templates-json-schema/tree/group-id-rule

"if": {
  "properties": {
    "group": {
      "pattern": "^(?!\/s*$).+/"
    }
  },
  "required": [
    "group"
  ]
},
"then": {
  "#/groups": {
    "contains": {
      "type": "object",
      "properties": {
        "id": {
          "const": "${0/group}"
        }
      }
    }
  },
  "errorMessage": "invalid group id ${0/group}, not defined in groups"
}