ext_multigrid: Missing msg_set_pos and win_pos notifications upon reattach

[adament]

Neovim version (nvim -v)

0.7.2 and 0.7.0

Vim (not Nvim) behaves the same?

NA

Operating system/version

Linux NixOS

Terminal name/version

alacritty

$TERM environment variable

alacritty

Installation

GitHub binary release and NixOS 22.05 package

How to reproduce the issue

I use the following test.py script to emulate a super simple UI:

#!/usr/bin/env python
from pynvim import attach
nvim = attach('socket', path='my_socket')
def notification_cb(name, args):
    if name == 'redraw':
        print(f"Redraw events ({len(args)}):")
        for x in args:
            print(f"    {x[0]}")
    else:
        print(f"Notification {name}", args)
nvim.run_loop(
    lambda name, args: print(f'Request {name}:', args),
    notification_cb,
    lambda: nvim.api.ui_attach(100, 100, {'rgb': True, 'ext_linegrid': True, 'ext_multigrid': True}),
)

Then I run in one terminal:

nvim --clean --headless --listen 'my_socket'

And in another:

./test.py
<Ctrl-C>
./test.py
<Ctrl-C>

Expected behavior

I would expect to get functionally the same UI notifications upon first attach and later reattach of the UI. Specifically at least all the same message types should be sent for the first attach and later reattach.

Actual behavior

However upon reattach (second run of test.py) I do not get any win_pos or msg_set_pos notifications. Output of first ./test.py

Redraw events (17):
    option_set
    default_colors_set
    hl_attr_define
    hl_group_set
    option_set
    default_colors_set
    grid_resize
    grid_clear
    grid_resize
    msg_set_pos
    win_viewport
    grid_resize
    grid_line
    win_pos
    win_viewport
    grid_cursor_goto
    flush
Redraw events (4):
    mode_info_set
    mode_change
    mouse_off
    flush

Output of second:

edraw events (14):
    option_set
    default_colors_set
    hl_attr_define
    hl_group_set
    option_set
    default_colors_set
    grid_resize
    grid_clear
    win_viewport
    grid_resize
    grid_line
    win_viewport
    grid_cursor_goto
    flush
Redraw events (4):
    mode_info_set
    mode_change
    mouse_off
    flush

[williamhCode]

any updates on this issue?