st.slider returns an old value

Summary

Type here a clear and concise description of the bug. Aim for 2-3 sentences.

Steps to reproduce

What are the steps we should take to reproduce the bug:

1. Run this script:

max_val = st.selectbox("max", [5, 10, 15], 0)
val = st.slider("main", 0,  max_val, 0)
st.write(val)

1. Change the value of the “main” slider to 3
2. Change the value of the “max value” to 10
3. Change back the value of the “max” value to 5

Expected behavior:

The value of the st.write is 0, consistent with the default value of the “main” value and its current value.

Actual behavior:

The value of the st.write is 3 (old value)

Is this a regression?

?

Debug info

• Streamlit version: c2e9d6b0c268f986c2c8588e36bdec08e47f194e Python 3

Additional information

Interestingly, this does not repro if fromUi in

 this.setWidgetValue({ fromUi: false })

in componentDidMount in Slider.tsx is set to true instead of false.

[kmcgrady]

Our solution to this should be resolved with session state. I’ve tagged this issue in it to verify when we release.

[dchudz]

I spent a few minutes digging into the history so in case this saves anyone time: #349 was reverted by #753.

(I got here via https://discuss.streamlit.io/t/preserving-state-across-sidebar-pages/107/10 and FWIW it would help me out a lot for this bug to be addressed.)