Anywidget based widget exceeds MAX_OUTPUT_BYTES in marimo for no obvious reason

[paddymul]

Describe the bug

I have a widget that is throwing errors in Marimo, based on "Your output is too large". In my widget I store a large dataframe in a trait that should not be serialized to the frontend (I have separate ways of sending dataframe state).

Why would a trait without .tag(sync=True) result in the output size increasing?
Is there a way around this?

Reproduction

import pandas as pd
import numpy as np
import anywidget
import traitlets

def get_df(ROWS):
    return pd.DataFrame(
    {'int_col':np.random.randint(1,50, ROWS),
     'float_col': np.random.randint(1,30, ROWS)/.7,
     "str_col": ["foobar"] * ROWS})
    

class CounterWidget(anywidget.AnyWidget):
    _esm = """
    function render({ model, el }) {
      let button = document.createElement("button");
      button.innerHTML = `count is ${model.get("value")}`;
      button.addEventListener("click", () => {
        model.set("value", model.get("value") + 1);
        model.save_changes();
      });
      model.on("change:value", () => {
        button.innerHTML = `count is ${model.get("value")}`;
      });
      el.classList.add("counter-widget");
      el.appendChild(button);
    }
    export default { render };
    """
    _css = """
    .counter-widget button { color: white; font-size: 1.75rem; background-color: #ea580c; padding: 0.5rem 1rem; border: none; border-radius: 0.25rem; }
    .counter-widget button:hover { background-color: #9a3412; }
    """
    value = traitlets.Int(0).tag(sync=True)
    df = traitlets.Any({})

cw = CounterWidget(value=42, df=get_df(500_000))
cw

Logs

System Info

This was run against the latest version of marimo.  You can access the notebook here
https://marimo.app/#code/JYWwDg9gTgLgBCAhlUEBQaD6mDmBTAOzykRjwBNMB3YGACzgF44AiABgDoBGLjgDgC05PADcAbCzSIwYJgmSoOAQRkAKAJQY0AAWlgOAYzwAbY2mEAzOJg0AuNHEdxQkWHDCIC5RAGc4v93IHJxdoeAIAV3AAT38-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-NO58iDHGzonnwPg0Pd7jiZP9-1PYwOANGdPwIfBbEPK9l3UNcN3-Ps3VTdMCEzXNCxLMs1mcata3rUDz1gjt1C7IDe0ApMG3ZTkJ0xQdhxnXl+SgARxVKONKLRBs9EIcguToYBjHIVR+wIR9-wZTU8AAD1ceBLEQCJjHgM0jWEKBbR4px1Ukf8Nh8PxmH0zVDFYsh2M4l1UM9M1Ni+KA8SoYSyHjLUDRgAQfGAAAvPA8V4JEbj6EAPPJBccCgVjyAERzoDxABiPBEBuPg2AMDyPGHVYcDxThQrwVUuDCiLoC0vECANPByqgLSBBIM4Ih8AqOAAJiK8LbXM3CrI4oUsmTOyCFsOgIDHbSzUi+doti+KtkSuAkoATkQSEABYuHajyZP-Mz-1IuRCkQYpSh8DgAEkIzYdQOBgRAcFUHxogIAxGBzKB22ZXt6mOooYGdC6lClU0mVZRwDCoOQeXLAVBpFUjGA29qHnqRhanqVQ7jYTA2Hx9Qfshqgcj6GABiGWG2JlLIHjFBGYAeKGHkxiwHgSB4wHIB4TrOsotF0GRDBMMxqhsKH5UqKGOHqUn+kGAW9GF0xzDwKwbElpwyYprRgHVzACEQGZsCYUzsCQVZsFxHIla+ggNDQIA

Severity

annoyance

[manzt]

I just tried the link you shared, and it seems to be working. I see a regular count output when running the provided code and no indication of MAX_OUTPUT_BYTES. I'm also not able to reproduce the issue on marimo v0.11.17.

Why would a trait without .tag(sync=True) result in the output size increasing?

It shouldn't. marimo's anywidget integration (to my understanding) correctly syncs data.

As an aside, make sure to wrap your anywidgets in marimo with mo.ui.anywidget.

[paddymul]

I refactored my widget around this so I'm not longer affected. But the behavior definitely exists from my testing. Did you make any code changes? A documentation update might be helpful.

[manzt]

As mentioned, I do not see MAX_OUTPUT_BYTES with either the link you shared to the marimo playground nor locally with the same example as of marimo v0.11.17.

I am happy to reopen with more information and a minimum reproducible example.

[paddymul]

Ugh. I just tried to reproduce and I can't. I'm sorry.

I swear I was seeing that example throw the MAX_OUTPUT_BYTES error.

[manzt]

All good. Sorry for closing without an additional comment. Please let me know if it comes up again and you can reproduce.