[issue44076] issue with list in Python 3.8.5

[Steven D'Aprano]

Steven D'Aprano <steve+python at pearwood.info> added the comment:

On Sun, May 09, 2021 at 11:55:56PM +0000, Mohamed wrote:

> Please find attached, the demo with dummy data. As I mentioned, it was working fine until May 1st. 

If it was working fine until May 1st, I would start my investigation by 
looking at what changes where made to the source code on April 29, 30 
and May 1st.

Is your source code in a source control repository? Can you compare it 
to a backup?

> Also, As I mentioned, in case I call MasterApp at the end of add 
> function data appears correctly. This means a malfunction occurred 
> after Windows Update, and it relates to mainloop

Your traceback involves a keyerror and an index error. What makes you 
think this is a problem with the Tkinter mainloop rather than your own 
code?

You are trying to delete a module from sys.modules:

    del sys.modules['cm_asset_add']

(why?) but the key is not found. That exception is then caught and 
another exception raised.

It really looks to me that your callback function fun_asset_current is 
buggy. Why is it messing with sys.modules?

>     class MasterApp(object):
>         def __init__(self, root):
>         ....
> 
>         def fun_astinfo_add(self):
> 	    ...
> 	    assetinfo_lst.append(lst_values)
> 	    ...
> 	    MasterApp(root)

I'm not an expert at tkinter, but creating a new MasterApp object 
every single time you call the fun_astinfo_add method doesn't look 
right to me -- especially since you create that object, but then 
immediately discard it and it is instantly garbage collected.

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue44076>
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