preview-tui does not work with tmux 3.4

[ListeriaM]

Environment details

• Operating System: Arch Linux
• Desktop Environment:
• Terminal Emulator: st + tmux 3.4
• Shell:
• Custom desktop opener (if applicable):
• Program options used: -Pp
• Configuration options set:
• Plugins are installed
• Issue exists on nnn master

Exact steps to reproduce the issue

NNN_PLUG='p:-preview-tui' tmux new-session nnn -Pp

you should get a "size missing" error from tmux.

The problem

The -p option to split-window was deprecated in tmux version 3.1 in favor of -l ...% (maybe irrelevant).
It was broken in 3.4, which I suspect is a bug since they're changing it for 3.5.

[luukvbaal]

#1812 (comment)