Lonboard (anywidget) map not rendering layers

[fabito]

Describe the bug

Lonboard map visualization not working as expected.
Layers aren't rendered.

Environment

{
  "marimo": "0.11.9",
  "OS": "Darwin",
  "OS Version": "22.6.0",
  "Processor": "arm",
  "Python Version": "3.11.7",
  "Binaries": {
    "Browser": "133.0.6943.127",
    "Node": "v20.17.0"
  },
  "Dependencies": {
    "click": "8.1.8",
    "docutils": "0.21.2",
    "itsdangerous": "2.2.0",
    "jedi": "0.19.2",
    "markdown": "3.7",
    "narwhals": "1.28.0",
    "packaging": "24.2",
    "psutil": "7.0.0",
    "pygments": "2.19.1",
    "pymdown-extensions": "10.14.3",
    "pyyaml": "6.0.2",
    "ruff": "0.9.7",
    "starlette": "0.46.0",
    "tomlkit": "0.13.2",
    "typing-extensions": "4.12.2",
    "uvicorn": "0.34.0",
    "websockets": "15.0"
  },
  "Optional Dependencies": {
    "anywidget": "0.9.14",
    "duckdb": "1.2.0",
    "pandas": "2.1.4",
    "polars": "1.23.0",
    "pyarrow": "19.0.1"
  },
  "Experimental Flags": {
    "chat_sidebar": true,
    "multi_column": true
  }
}

Code to reproduce

More details in #3908

The expected map should look like:

But I am getting:

[mscolnick]

I did a bit of digging.

This field is returning undefined when it expects a list of ids https://github.com/developmentseed/lonboard/blob/510af74c550eced13a79d80f16cee38b98df69b7/src/index.tsx#L137

But this is the initial state that marimo passes to the widget.

{
    "_height": null,
    "basemap_style": "https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.json",
    "custom_attribution": "",
    "parameters": null,
    "picking_radius": 5,
    "selected_bounds": null,
    "show_tooltip": true,
    "use_device_pixels": null,
    "view_state": [
        -48.32,
        -25.340000000000003,
        9,
        0,
        0
    ]
}

Still not sure if its a marimo error on lonboard

[mscolnick]

It is this trailet that is not being passed.

https://github.com/developmentseed/lonboard/blob/510af74c550eced13a79d80f16cee38b98df69b7/lonboard/_map.py#L186C14-L189

Likely because we don't support custom traitlet serialization, but there might be another reason.

[mscolnick]

Got further in #3921, with the serialization, but marimo doesn't support the widget_manager (at least yet), and lonboard does make use of this, so still will be an error

cc @manzt, do you know what it would take to support widget_manager in marimo?

[manzt]

The main thing necessary to support he widget_manger is the ability for other widgets to access instances of Model by some id. I think some Map<modelId, Model> would allow for implementing such a thing:

  widget_manger: {
    get_model(model_id: string): Model {
      return MODELS.get(model_id)
    }
  }

I'd be happy to help land this as I know a few more sophisticated anywidgets use this feature. Every ipywidget.Widget has a model_id. When created, it emits a a "open_open" event to the front end with the initial state. This creates an evented Model object, regardless of whether there is a corresponding view for that model. The widget_manager lets other views access (and subscribe to methods on other other models that are in the front end).

conceptually, for marimo I think this would entail creating a "global" registry of Model instances. Any time a Widget is instantiated on the Python side, it should create an instance on the front end keyed in the registry by it's corresponding ID.

[mscolnick]

@manzt, would love your help on this in any capacity

[manzt]

Sure, i could find time next week to pair