plotly / plotly/dash

[BUG] Client side error in plotly when trying to draw a heatmap with height set and just a few values.

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#3,363 1 comment 1 reaction 1 assignee View on GitHub

@T4rk1n is already working on this.

Since Jul 3, 2025.

bug P1 regression
Dominant language
Python
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Description

I'm using dash 3.1.1 installed from python3.13.5 virtual env from ubuntu24.0.4.2LTS.

When I run this minimal example:

import dash
from dash import dcc, html
import plotly.express as px
import pandas as pd

df = pd.DataFrame({"x": ["Out Of Bounds Read or Write"] * 15, "y": [9.8] * 15})
fig = px.density_heatmap(df, x="x", y="y")

app = dash.Dash(__name__)
app.layout = html.Div(
    [
        dcc.Graph(
            figure=fig,
            style={"height": 100},
        )
    ]
)

if __name__ == "__main__":
    app.run(debug=True)

The web page stays blank instead of displaying the chart, and I can see the following error message on dev tools from my browser:

Uncaught (in promise) Error: Something went wrong with axis scaling
    setScale plotly.min.js:20
    lmt plotly.min.js:21
    omt plotly.min.js:21
    each plotly.min.js:15
    bt plotly.min.js:15
    each plotly.min.js:15
    omt plotly.min.js:21
    drawMarginPushers plotly.min.js:21
    b plotly.min.js:21
    syncOrAsync plotly.min.js:20
    nht plotly.min.js:21
    lht plotly.min.js:21
    _ht plotly.min.js:21
    plot React
plotly.min.js:20:174757

On the top of this plotly.min.js I have:

/**
* plotly.js v3.0.1
* Copyright 2012-2025, Plotly, Inc.
* All rights reserved.
* Licensed under the MIT license
*/

When I comment the line style={"height": 100}, everything is working well.

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