Clarify in docs that variabletype needs to be set in Toolbox XML when using typed variables

[YannCaron]

This problem lead me to craziness :-) I think it is a bug.

A want to create a custom type called 'Actor' to manage some object in my game engine.

But if I setup the type of the field_variable as well :

{
  "type": "field_variable",
  "name": "NAME",
  "variable": "hero",
  "validator": null,
  "variableTypes": ["Actor"],
  "defaultType": "Actor"
}

And I want to setup the value of this field within the tookbox definition (I also tried with a shadow block, same issue) :

<block type="actor_create" inline="true">
  <field name="NAME">hero</field>
</block>

NB: the block definition is into a dynamic category, so the 'hero' variable exists at the block definition time :-)

Even if 'hero' is an Actor object, it's lead to this error

Error: Variable type doesn't match this field! Type was 

I turn around from a long time with that and searched on google to find solutions, but nothing.
I know that defaultType is mandatory and everything seems OK, that's why I think it is a bug.

Here is the 'actor_create' definition :

{
  "type": "actor_create",
  "args0": [
    {
      "type": "field_variable",
      "name": "NAME",
      "variable": "hero",
      "validator": null,
      "variableTypes": [
        "Actor"
      ],
      "defaultType": "Actor"
    },
    {
      "type": "input_value",
      "name": "IMG",
      "check": "Image"
    },
    {
      "type": "input_value",
      "name": "X",
      "check": "Number"
    },
    {
      "type": "input_value",
      "name": "Y",
      "check": "Number"
    }
  ],
  "inputsInline": true,
  "colour": "%{BKY_ACTOR_HUE}",
  "message0": "%{BKY_ACTOR_CREATE_MSG}",
  "tooltip": "%{BKY_ACTOR_CREATE_HELP}",
  "helpUrl": "%{BKY_ACTOR_CREATE_URL}",
  "previousStatement": null,
  "nextStatement": null
}

[RoboErikG]

How are you creating the 'hero' variable? Are you calling createVariable with the optional type set to Actor?
Blockly.Variables.createVariable(workspace, null, 'Actor');

[YannCaron]

Hello @RoboErikG , No, I am using
Blockly.Variables.createVariableButtonHandler(button.getTargetWorkspace(), null, 'Actor'); with a button

[YannCaron]

Something is that 'hero' variable seems to be created 2 times :

PS: OK, I think I understand what's append now :
It appears it is due to that block definition in the workspace :

<block type="actor_create" inline="true">
  <field name="NAME">hero</field>
</block>

It seems that blockly try to create the variable 'hero' again when I use this declaration.

[RoboErikG]

Ah, gotcha. You need to add a type attribute to the toolbox xml.

<field name="NAME" variabletype="Actor">hero</field>

We should probably update the documentation at the least to make this clearer. We could potentially infer the type when it's in the toolbox, but there are a lot of corner cases where that could cause problems.

[YannCaron]

Brilliant @RoboErikG It's works perfectly ! Many thanks.
I am just surprised that it is not camel case formatted like other attributes ("variableType") but anyway, the most important is that it is working and let me carry on my project :-)
Thanks again and keep up the good job 👍

[rachel-fenichel]

Oh yeah, the lack of camel casing is because attributes get forced to lowercase in setAttribute (either on XML or HTML DOM elements, I don't remember which). I agree that it's a mismatch with everything else we do.

[RoboErikG]

Toolbox page will get a new section on variables next week.

[YannCaron]

Great ! Many thanks !