The issue is that plotly's template system has a circular import dependency:

1. plotly.graph_objs.__init__.py imports all trace types including Heatmapgl
2. During this import process, it also loads template data
3. layout/template/data/_heatmapgl.py tries to import Heatmapgl from plotly.graph_objs
4. But plotly.graph_objs is still in the process of being imported!

This occurred when attempting to use plotly and plotly-resampler and a heatmap.

Reproduction of Error

Minimal reproduction code:

import plotly.graph_objs as go
go.Heatmapgl() # ✅ Success
# But this fails:
from plotly_resampler import FigureResampler
fig = FigureResampler(go.Figure()) # ❌ Circular import

Versions affected:

plotly==5.24.1
plotly-resampler==0.10.0

Work around

This can be worked around by forcing import order:

import plotly.graph_objs # Force full initialization first
from plotly_resampler import FigureResampler # Then import resampler