Typeshed for tkinter invalidcommand is not correct

[rafrafek]

The typeshed for tkinter ttk.Entry.invalidcommand uses tkinter._EntryValidateCommand type annotation which means

TypeAlias = str | list[str] | tuple[str, ...] | Callable[[], bool]

https://github.com/search?q=repo%3Apython%2Ftypeshed%20invalidcommand&type=code

but it should use something like

Callable[[], None]

invalidcommand is just a function that is called when the validatecommand returns False. I think it is undocumented in the Python docs.

Example snippet for tests:

from tkinter import DoubleVar, Tk
from tkinter.ttk import Button, Entry, Frame, Label

root = Tk()
root.resizable(False, False)
validate_value = root.register(lambda value: False), "%P"
frame = Frame(root, padding=10)
frame.grid()
Label(frame, text="Hello World!").grid(column=0, row=0)
txt = DoubleVar(value=4.5)
Label(frame, textvariable=txt).grid(column=1, row=1)
Entry(
    frame,
    textvariable=txt,
    validate="all",
    validatecommand=validate_value,
    invalidcommand=lambda: print("Validation error!"),  # <-- Wrong typeshed
).grid(column=1, row=2)
Button(frame, text="Quit", command=root.destroy).grid(column=2, row=3)
root.mainloop()

The lambda below should be allowed here:

But it is marked as an error by Pyright due to the wrong typeshed.

This issue is moved from microsoft/pyright#5720

[Akuli]

I think the right type would be str | list[str] | tuple[str, ...] | Callable[[], object], with object instead of bool. PR welcome :)

The str is needed for passing a string of Tcl code. You can also pass a list or tuple to specify a command and arguments for it. These entries print asdf asdf when you edit the entry text:

tkinter.Entry(
    invalidcommand='puts "asdf asdf"',
    validate='all',
    validatecommand=(lambda: False),
).pack()

tkinter.Entry(
    invalidcommand=('puts', 'asdf asdf'),
    validate='all',
    validatecommand=(lambda: False),
).pack()