How to fix bad window path name error in simpledialog tkinter?

Question

Considering a basic app which is a class inheriting from tk.Tk, I get an unexpected error message when using the simpledialog module from tkinter. It is related to overriding the __str__ method in this class as the simpledialog does work without the string override, so my guess would be the simpledialog expects default behavior there. See the error message below:

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\**\Python39\lib\tkinter\__init__.py", line 1884, in __call__
    return self.func(*args)
  File "C:\**\bad_window_error.py", line 22, in start_dialog
    result = simpledialog.askstring('Simple dialog', 'Fill in a string..')
  File "C:\**\Python39\lib\tkinter\simpledialog.py", line 399, in askstring
    d = _QueryString(title, prompt, **kw)
  File "C:\**\Python39\lib\tkinter\simpledialog.py", line 376, in __init__
    _QueryDialog.__init__(self, *args, **kw)
  File "C:**\Python39\lib\tkinter\simpledialog.py", line 271, in __init__
    Dialog.__init__(self, parent, title)
  File "C:\**\Python39\lib\tkinter\simpledialog.py", line 138, in __init__
    self.transient(parent)
  File "C:\**\Python39\lib\tkinter\__init__.py", line 2225, in wm_transient
    return self.tk.call('wm', 'transient', self._w, master)
_tkinter.TclError: bad window path name "random"

I have put together a minimal example, see below. The actual code I am working on is much bigger with many dependencies and so far I have only noticed this error occurring with the simpledialog module.

import tkinter as tk
from tkinter import ttk
from tkinter import simpledialog, messagebox

class App(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title('Random app')
        self.option_add('*tearOff', False)

        self.start_dialog_button = ttk.Button(self, text='Run simple dialog', command=self.start_dialog)
        self.start_dialog_button.grid(row=0, column=0, sticky='nesw')

    def __str__(self):
        return "random"

    @staticmethod
    def start_dialog():
        messagebox.showinfo('hello', 'this works')
        result = simpledialog.askstring('Simple dialog', 'Fill in a string..')
        messagebox.showinfo('Result', result)

if __name__ == '__main__':
    app = App()
    app.mainloop()

If the string override is commented out, the code should run as expected. Is there a way to use the simpledialog module while still overriding the default __str__ method of tk.Tk or should I never do that?

Answer 1

IT's better not to override the default functions ; If you're looking to do it to change the output results, it can easily be done without creating extra issues.

@staticmethod
def start_dialog():
    messagebox.showinfo('hello', 'this works')
    result = simpledialog.askstring('Simple dialog', 'Fill in a string..')
    
    if (result is None or result == '') :
        result="random"
    
    else:
        result=result+" this should work"
    messagebox.showinfo('Result', result)