KeyError (only in terminal) when accessing session_state key in a multipage app

[luxiaolei]

KeyError (only in terminal) when accessing session_state key in a multipage app

[Asaurus1]

I suspect this will go away if you add a if "my_val" in st.session_state guard to your subpage, but agree that doesn't explain why you would get an issue only in your terminal.

[Asaurus1]

I'm not able to reproduce this error with the latest version of streamlit. I am able to produce key errors if I refresh and go directly to the "mypage.py" page (e.g. start a session on that page) which makes sense, since my_val doesn't exist yet. But those key errors also show up in the app.

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[raethlein]

Thanks @Asaurus1 for responding to this! I agree with your assessment that in general if "my_val" in st.session_state should guard against this behavior. Indeed, if you start the app and go directly to /mypage, I get a key error, which is expected as explained above. As I am also not able to reproduce any other behavior, I am going to close the issue. @luxiaolei feel free to re-open the issue if you have more details on how this can be reproduced or feel the original issue was misunderstood 🙂