bar chart: textposition='auto' not working for 0 values #6474

From the textposition argument documentation for bar traces:

"auto" tries to position text inside the bar, but if the bar is too small and no bar is stacked on this one the text is moved outside.

For small values this is working nicely: Instead of inside, the text gets positioned outside.

But: For 0 values, the text disappears completely instead of being moved outside.

import pandas as pd
import plotly.express as px

df = pd.DataFrame({
    "Country": [f"Country {n}" for n in range(6)],
    "Some Metric": [8,5,5,.5,0.0001,0]
})

fig = px.bar(
    df, 
    x='Some Metric',
    y='Country', 
    text='Country',
    orientation='h')
fig.update_yaxes(visible=False, showticklabels=False)

# change here between "auto" (default), "inside", "outisde"
fig.update_traces(textposition="auto")

fig.show()

Setting 0 values to a small value is a dirty fix that may also lead to the text disappearing when the graph is resized. At the same time, such a fix endangers data integrity.

The alternative would be setting the textposition for every observation separately. I think that should be avoided and covered by setting texposition="auto".

Fix that everybody can implement in their code currently:

fig.update_traces(textposition=['outside' if val==0 else 'auto' for val in df['Some Metric']])

Tested with plotly 5.10.0.