Callbacks erroring on unrelated views - Solved

Dash Python
1

Hi there. Have had a bit of a hunt but haven’t been able to track down a solution.

I have a multi-page app with various different views that are linked via a homepage. My issue is that on page “A” I get the error:
ReferenceError: A nonexistent object was used in an `Input` of a Dash callback.
The object that is being referenced in the error above is actually from page “B”.

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Conversely, when viewing page “B”, the above error shows again, but this time for a callback that is present in page “A”.

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Sure enough, commenting out the callback in one of the pages removes the error from the other.

The callbacks in question:

reports.py

@app.callback(
    Output('data_div', 'children'),
    [
        Input('report_choice', 'value'),
        ...
        Input('submit_button', 'n_clicks'),
    ]
)
def generate_report(
        report_choice,
        ...
        submit_button_clicks
):

items.py

@app.callback(
    [
        Output('item_code', 'children'),
        ...
        Output('data_div', 'hidden'),
    ],
    [
        Input('given_item_string', 'value'),
        Input('given_store', 'value'),
        Input('submit_button', 'n_clicks'),
    ]
)
def update_item_view(given_item_string, given_store, submit_button):

Is there something i’m missing in understanding how the callbacks should be behaving?
Let me know if i can clarify anything. Any help would be appreciated.

Cheers!

2

So after bit of brick-wall-headbanging, it seems that the Outputs of callbacks have to be unique, even if they are in completely separate locations and don’t interact with each other. News to me.

Having Output('data_div', 'XXX') in both callbacks seemed to be causing the problem.

Regardless, issue seems fixed.