Yanking to ?+ register does not work in Emacs >=29 about evil HOT 6 OPEN

I'm confused as to why you would bother with specifying the + register at all when select-enable-clipboard is t?

p/P gets buggy sometimes and does not paste from clipboard. I don't know how to reproduce it and even whether it has something to do with evil. C-r + works every time. It's kind of muscle memory for me.

Doesn't that essentially make + the default register?

not sure what letter is associated with default register, but from quick testing it seems I can use C-r 1 instead of C-r +.

from evil.

I'm confused, do you hit this bug on Emacs 29? Or Only 30? I can't reproduce it on 29, FWIW.

from evil.

I can reproduce this on:

1. Emacs 30.0.50 on Ubuntu 22.04, Emacs was built from sources, with native compilation
2. Emacs 29.1 on ArchLinux, installed via pacman (package emacs-nativecomp)

from evil.

What are your values of variables:

• window-system
• select-enable-clipboard

Mine is:

• x
• t
  If your window-system is not in '(x haiku) or the second variable is nil, then that's why it is working for you.

from evil.

A comment from gui-last-cut-in-clipboard

;; The doc string of `interprogram-paste-function' says to return
  ;; nil if no other program has provided text to paste.

I think it means that if you copied text to clipboard from Emacs then this function should return nil.
unless statement that I pasted in the first message checks exactly this.
It may be useful for something, but evil uses this function to get the last value from the clipboard.
So I think that it is pretty safe to override gui-last-cut-in-clipboard locally, before invocation of this function.

(let ((gui-last-cut-in-clipboard nil))
        (gui--selection-value-internal what))

unless statement will always succeed in this case.

from evil.

Also, up until a couple months ago I ran Emacs 29 on Arch Linux with window-system == pgtk, never noticed the issue you describe.

I can reproduce the "Register '+' is empty" error by setting select-enable-clipboard to t on my NixOS system (but not on MacOS).

I'm confused as to why you would bother with specifying the + register at all when select-enable-clipboard is t? Doesn't that essentially make + the default register? My intention in asking is not to dismiss this bug report entirely -- the "register is empty" error is clearly not the correct behavior -- just trying to understand the severity/impact of the problem.

from evil.