Bug report

Bug description:

If you run de following code:

importtkinterastkclassLabel2(tk.Label):def__init__(self,top,text):tk.Label.__init__(self,top,text=text,bg='Yellow')w=tk.Tk()w.columnconfigure((0,1,2),weight=1,uniform='u1')label_1=tk.Label(w,text='Native Label\nInstance 1',bg='LightGreen')label_1.grid(column=0,row=0)label_2=Label2(w,text='Label2 Label\nInstance 1')label_2.grid(column=1,row=0)label_3=tk.Label(w,text='Native Label\nInstance 2',bg='LightGreen')label_3.grid(column=2,row=0)w.mainloop()

It will produce the following result (only label_1 and label_3 seems to be placed) :

instead of what you expect (the following result) :

Note: This code is using Label for simplicity but it's the same with other widgets !

Explanation:
This is because of automatic generated tkinter widget names:
label_1 name is '.!label'
label_2 name is '.!label2'
label_3 name is '.!label2'

So 'label_2' and 'label_3' has the same widget name.
If you print the 'w.winfo_children()' function just before the 'w.mainloop()', you just get 2 widgets in the list.
The 'label_3' override the 'label_2' because for tkinter they are the same !

To get around this bug:

• you should not name your class by simply adding a number (like '2' or '3' ...)
• or you must give a unique name of your class instance with the 'name=' option in the Label constructor.

To correct the bug:
The naming algorithm should check that the automatically generated name is not already in use.

CPython versions tested on:

3.9, 3.13

Operating systems tested on:

Linux, Windows

Linked PRs

• gh-128562: Fix tkinter widget instance name sometimes duplicated on inherited class #128604
• [3.13] gh-128562: Fix generation of the tkinter widget names (GH-128604) #128791
• [3.12] gh-128562: Fix generation of the tkinter widget names (GH-128604) #128792