bug#69056: 30.0.50; history-add-new-input and recursive minibuffers

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 11 Feb 2024 16:54:43 +0100
> From:  Eshel Yaron via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 
> 1. emacs -Q
> 2. (setq enable-recursive-minibuffers t)
> 3. M-y
> 4. In the minibuffer (with the prompt "Yank from kill-ring: "),
>    type M-x calendar RET (or any other command).
> 5. M-x M-p
>    Expected: "calendar" is inserted in the minibuffer.
>    Observed: error saying "Beginning of history; no preceding item".
> 
> The problem is that the minibuffer history of M-x isn't recorded when
> you invoke M-x from within the minibuffer of read-from-kill-ring (M-y).
> The reason is that read-from-kill-ring let binds history-add-new-input,
> and that affects all recursive minibuffers as well, so no minibuffer
> history is recorded until you exit the first (non-recursive) minibuffer.
> 
> AFAICT This issue affects all uses history-add-new-input, unfortunately,
> not only read-from-kill-ring, since it's always used via let-bindings.

I'm not sure we should be interested in fixing this.  Recursive
minibuffers are not supposed to start a completely new command loop
unaffected by whatever was before it, so we shouldn't try.  Even if
this particular case is solved (which I'm not sure we can), there are
a legion of other similar situations, where something let-bound by a
command entering the minibuffer affects all the recursive minibuffers.
Let-binding in commands that prompt users is ubiquitous in Emacs.

It's easy enough to work around the problem: C-g (perhaps more than
once), then start afresh.

So I tend to close this as wontfix.