Package: emacs;
Reported by: Eshel Yaron <me <at> eshelyaron.com>
Date: Wed, 17 Jan 2024 19:45:02 UTC
Severity: minor
Tags: patch
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From: Stefan Kangas <stefankangas <at> gmail.com> To: João Távora <joaotavora <at> gmail.com> Cc: Eli Zaretskii <eliz <at> gnu.org>, Eshel Yaron <me <at> eshelyaron.com>, 68547 <at> debbugs.gnu.org Subject: bug#68547: [PATCH] ; Fix 'mode-line-format-right-align' with ElDoc Date: Wed, 5 Mar 2025 19:31:01 -0800
João Távora <joaotavora <at> gmail.com> writes:
> On Sat, Jan 20, 2024 at 3:33 PM Eshel Yaron <me <at> eshelyaron.com> wrote:
>
>> Then I tried the following (somewhat pathological) use case:
>>
>> 0. Setup: (keymap-global-set "C-x w a" #'windmove-swap-states-left)
>> 1. Open two buffers in two windows side by side.
>> 2. Say `M-: (car `, to show info in the mode line of the left window.
>> 3. Without quitting the minibuffer, use `C-x o` to switch to the right
>> window, followed by `C-x w a` to switch the buffers in the left and
>> right windows.
>> 4. Return to the minibuffer and type `nil) RET` or something like that
>> to exit the minibuffer.
>> 5. The `mode-line-format` of the left buffer is becomes nil, i.e. no mode line.
>>
>> Shuffling `mode-line-format` around is really tricky :(
>
> Indeed. Your case is pathological, but not particularly hard to
> trigger. Given the consequences are somewhat dire (vanished mode-line)
> , it should most definitely be handled.
>
> Try this version, please. Only difference is it uses a setq-local
> for eldoc--saved-mlf instead of a setq.
>
> Please give it as much testing as you can.
>
> João
Was this installed? If not, should it be?
> diff --git a/lisp/emacs-lisp/eldoc.el b/lisp/emacs-lisp/eldoc.el
> index 912a7357ca7..1ba4e6a006f 100644
> --- a/lisp/emacs-lisp/eldoc.el
> +++ b/lisp/emacs-lisp/eldoc.el
> @@ -182,7 +182,7 @@ eldoc-current-idle-delay
> "Idle time delay currently in use by timer.
> This is used to determine if `eldoc-idle-delay' is changed by the user.")
>
> -(defvar eldoc-message-function #'eldoc-minibuffer-message
> +(defvar eldoc-message-function #'eldoc--minibuffer-message
> "The function used by `eldoc--message' to display messages.
> It should receive the same arguments as `message'.")
>
> @@ -292,43 +292,42 @@ eldoc-schedule-timer
> (setq eldoc-current-idle-delay eldoc-idle-delay)
> (timer-set-idle-time eldoc-timer eldoc-idle-delay t))))
>
> -(defvar eldoc-mode-line-string nil)
> -(put 'eldoc-mode-line-string 'risky-local-variable t)
> -
> -(defun eldoc-minibuffer-message (format-string &rest args)
> +(defvar eldoc--saved-mlf nil
> + "Saved `mode-line-format' used in `eldoc--minibuffer-message'.")
> +(defun eldoc--minibuffer-message (format-string &rest args)
> "Display message specified by FORMAT-STRING and ARGS on the
> mode-line as needed.
> This function displays the message produced by formatting ARGS
> with FORMAT-STRING on the mode line when the current buffer is a minibuffer.
> Otherwise, it displays the message like `message' would."
> - (if (or (bound-and-true-p edebug-mode) (minibufferp))
> - (progn
> - (add-hook 'post-command-hook #'eldoc-minibuffer--cleanup)
> - (with-current-buffer
> - (window-buffer
> - (or (window-in-direction 'above (minibuffer-window))
> - (minibuffer-selected-window)
> - (get-largest-window)))
> - (when (and mode-line-format
> - (not (and (listp mode-line-format)
> - (assq 'eldoc-mode-line-string
> mode-line-format))))
> - (setq mode-line-format
> - (funcall
> - (if (listp mode-line-format) #'append #'list)
> - (list "" '(eldoc-mode-line-string
> - (" " eldoc-mode-line-string " ")))
> - mode-line-format)))
> - (setq eldoc-mode-line-string
> - (when (stringp format-string)
> - (apply #'format-message format-string args)))
> - (force-mode-line-update)))
> - (apply #'message format-string args)))
> -
> -(defun eldoc-minibuffer--cleanup ()
> - (unless (or (bound-and-true-p edebug-mode) (minibufferp))
> - (setq eldoc-mode-line-string nil
> - ;; https://debbugs.gnu.org/16920
> - eldoc-last-message nil)
> - (remove-hook 'post-command-hook #'eldoc-minibuffer--cleanup)))
> + (cond ((bound-and-true-p edebug-mode)
> + (eldoc--message-in-mode-line 'edebug-mode-hook format-string args))
> + ((minibufferp)
> + (eldoc--message-in-mode-line 'minibuffer-exit-hook
> format-string args))
> + (t
> + (apply #'message format-string args))))
> +
> +(defun eldoc--message-in-mode-line (hook format-string args)
> + (with-current-buffer
> + (window-buffer
> + (or (window-in-direction 'above (minibuffer-window))
> + (minibuffer-selected-window)
> + (get-largest-window)))
> + (let ((buf (current-buffer)))
> + (cl-labels ((cleanup ()
> + (with-current-buffer buf
> + (remove-hook hook #'cleanup)
> + (setq mode-line-format eldoc--saved-mlf
> + eldoc--saved-mlf nil))))
> + (add-hook hook #'cleanup)
> + (setq-local eldoc--saved-mlf (or eldoc--saved-mlf mode-line-format))
> + (when format-string
> + (setq-local
> + mode-line-format
> + (funcall (if (listp eldoc--saved-mlf) #'cons #'list)
> + (and format-string
> + (apply #'format-message format-string args))
> + eldoc--saved-mlf)))
> + (force-mode-line-update)))))
>
> (make-obsolete
> 'eldoc-message "use `eldoc-documentation-functions' instead." "eldoc-1.1.0")
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