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Preserve widget state when a widget disappears from the page (demoed via Multipage Apps)

See original GitHub issue

Checklist

I have searched the existing issues for similar issues.
I added a very descriptive title to this issue.
I have provided sufficient information below to help reproduce this issue.

Summary

When you set a session state variable via the

st.some_input_widget(..., key="foo")

The value of session_state.foo is overridden when you leave that page and go back to that page.

I created an example of this which you can see here

Reproducible Code Example

# See the live example on Streamlit Community Cloud

Steps To Reproduce

Go to the live app.
Type in “ABC” in the text box which should bind it to the state variable “foo”
Optionally, click the button to set the “bar” state (this is included only to show that other forms of state are properly preserved across state views).
Click on the second page.
Click back to the main page.

Expected Behavior

When you complete step (5) the text you entered (“ABC”) should still be be bound to “foo” and appear on that page.

Current Behavior

“foo” has been overridden when you go back to the main page.

Is this a regression?

Yes, this used to work in a previous version.

Debug info

Streamlit version: 1.15.2
Python version: 3.10.6
Operating System: MacOS 12.6.1 (21G217)
Browser: Chrome Version 107.0.5304.121 (Official Build) (arm64)
Virtual environment: Python venv

Additional Information

No response

Are you willing to submit a PR?

Yes, I am willing to submit a PR!

Issue Analytics

State:
Created 10 months ago
Reactions:1
Comments:6

Top GitHub Comments

1reaction

jriekecommented, Dec 7, 2022

Also made a note for myself to dig deeper into this once I have some free time. Lots going on right now!

0reactions

matkozakcommented, Dec 9, 2022

Hi @kmcgrady, thanks a lot for taking this into consideration.

I think that for common use cases, the persistent state as default makes more sense. For example in a multi-step form entry for a CRUD app, or in a complex computation with multiple parameters grouped in tabs/pages, you normally would not want the application state to be reset just because the entry widget is hidden.