On 15/03/2026, Paul D. Nelson wrote:
> I think the (require ...) here will inhibit lazy-loading of buframe.
> Also, it returns a raw file-missing error rather than a user-error.
>
[...]
> It seems to me that this "else" branch will run whenever
> preview--update-buframe is called, independent of whether the user
> selected 'buframe for preview-at-point-placement.
>
> Moreover, the setq will not happen because it comes after the error.
>

If we want to lazily load buframe (only when needed rather than when
setting `preview-at-point-placement`), then we can consider the attached
patch.

Best regards,
-- Al
>From 866db377ce2330a8cbcc92a5f67effa31c254887 Mon Sep 17 00:00:00 2001
From: Al Haji-Ali <[email protected]>
Date: Mon, 16 Mar 2026 13:02:31 +0000
Subject: [PATCH] Lazily require buframe before use.

* preview.el (preview--buframe-error): New variable.
(preview--update-buframe): Require buframe before use.
---
 preview.el | 111 +++++++++++++++++++++++++++++------------------------
 1 file changed, 61 insertions(+), 50 deletions(-)

diff --git a/preview.el b/preview.el
index b253ef88..0b3ba0a4 100644
--- a/preview.el
+++ b/preview.el
@@ -4586,61 +4586,72 @@ If not a regular release, the date of the last change.")
 (declare-function buframe-find "ext:buframe"
                   (&optional frame-or-name buffer parent noerror))
 
+(defvar preview--buframe-error t
+  "When non-nil, issue a one-time error if loading buframe fails.")
+
 (defun preview--update-buframe (&optional force)
   "Show or hide a buframe popup depending on overlays at point.
 
 The frame is not updated if the `buframe' property has not changed,
 unless FORCE is non-nil."
-  (when (featurep 'buframe)
-    (let* ((frame-name "auctex-preview")
-           (buf-name " *auctex-preview-buffer*")
-           (old-frame (buframe-find frame-name nil nil t)))
-      (if-let* ((ov (cl-find-if
-                     (lambda (ov) (when (overlay-get ov 'buframe) ov))
-                     (overlays-at (point))))
-                (str (overlay-get ov 'buframe)))
-          (unless (and (not force)
-                       old-frame
-                       (pcase (frame-parameter old-frame 'auctex-preview)
-                         (`(,o . ,s) (and (eq o ov) (eq s str)))))
-            (let* ((buf (buframe-make-buffer buf-name
-                                             (car-safe
-                                              (cddr (cdr-safe
-                                                     preview-at-point-placement)))))
-                   (max-image-size
-                    (if (integerp max-image-size)
-                        max-image-size
-                      ;; Set the size max-image-size using the current frame
-                      ;; since the popup frame will be small to begin with
-                      (* max-image-size (frame-width)))))
-              (with-current-buffer buf
-                (let (buffer-read-only)
-                  (with-silent-modifications
-                    (erase-buffer)
-                    (insert (propertize str
-                                        ;; Remove unnecessary properties
-                                        'help-echo nil
-                                        'keymap nil
-                                        'mouse-face nil))
-                    (goto-char (point-min)))))
-              (setq old-frame
-                    (buframe-make
-                     frame-name
-                     (lambda (frame)
-                       (funcall
-                        (or (car-safe (cdr-safe preview-at-point-placement))
-                            #'buframe-position-right-of-overlay)
-                        frame
-                        ov))
-                     buf
-                     (overlay-buffer ov)
-                     (window-frame)
-                     (car-safe (cdr (cdr-safe preview-at-point-placement)))))
-              (set-frame-parameter old-frame 'auctex-preview
-                                   (cons ov str))))
-        (when old-frame
-          (set-frame-parameter old-frame 'auctex-preview nil)
-          (buframe-disable old-frame))))))
+  (let* ((frame-name "auctex-preview")
+         (buf-name " *auctex-preview-buffer*")
+         (old-frame (and (featurep 'buframe)
+                         ;; Don't load buframe if not already loaded
+                         (buframe-find frame-name nil nil t))))
+    (if-let* ((ov (cl-find-if
+                   (lambda (ov) (when (overlay-get ov 'buframe) ov))
+                   (overlays-at (point))))
+              (str (overlay-get ov 'buframe)))
+        (unless (and (not force)
+                     old-frame
+                     (pcase (frame-parameter old-frame 'auctex-preview)
+                       (`(,o . ,s) (and (eq o ov) (eq s str)))))
+          (if (require 'buframe nil t)
+              (let* ((buf (buframe-make-buffer
+                           buf-name
+                           (car-safe
+                            (cddr (cdr-safe
+                                   preview-at-point-placement)))))
+                     (max-image-size
+                      (if (integerp max-image-size)
+                          max-image-size
+                        ;; Set the size max-image-size using the current frame
+                        ;; since the popup frame will be small to begin with
+                        (* max-image-size (frame-width)))))
+                (with-current-buffer buf
+                  (let (buffer-read-only)
+                    (with-silent-modifications
+                      (erase-buffer)
+                      (insert (propertize str
+                                          ;; Remove unnecessary properties
+                                          'help-echo nil
+                                          'keymap nil
+                                          'mouse-face nil))
+                      (goto-char (point-min)))))
+                (setq old-frame
+                      (buframe-make
+                       frame-name
+                       (lambda (frame)
+                         (funcall
+                          (or (car-safe (cdr-safe preview-at-point-placement))
+                              #'buframe-position-right-of-overlay)
+                          frame
+                          ov))
+                       buf
+                       (overlay-buffer ov)
+                       (window-frame)
+                       (car-safe (cdr (cdr-safe
+                                       preview-at-point-placement)))))
+                (set-frame-parameter old-frame 'auctex-preview
+                                     (cons ov str)))
+            (when preview--buframe-error
+              (setq preview--buframe-error nil)
+              (error "buframe is unavailable for use with preview. \
+See `preview-at-point-placement'."))))
+      (when old-frame
+        (set-frame-parameter old-frame 'auctex-preview nil)
+        (buframe-disable old-frame)))))
 
 ;;;###autoload
 (defun preview-report-bug () "Report a bug in the preview-latex package."
-- 
2.50.1 (Apple Git-155)

_______________________________________________
bug-auctex mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/bug-auctex

Reply via email to