Avoid turning on the global-minor-mode recursively

* lisp/emacs-lisp/easy-mmode.el (define-globalized-minor-mode): Clear
the buffer-list inside MODE-enable-in-buffers to avoid enabling the
mode recursively.  (Bug#31793)

1 files changed, 16 insertions, 12 deletions

diff --git a/lisp/emacs-lisp/easy-mmode.el b/lisp/emacs-lisp/easy-mmode.el
index 21ca69324ed..443e03eb1a3 100644
--- a/lisp/emacs-lisp/easy-mmode.el
+++ b/lisp/emacs-lisp/easy-mmode.el
@@ -457,22 +457,26 @@ See `%s' for more information on %s."
 
        ;; The function that calls TURN-ON in each buffer.
        (defun ,MODE-enable-in-buffers ()
-         (dolist (buf ,MODE-buffers)
-           (when (buffer-live-p buf)
-             (with-current-buffer buf
-               (unless ,MODE-set-explicitly
-                 (unless (eq ,MODE-major-mode major-mode)
-                   (if ,mode
-                       (progn
-                         (,mode -1)
-                         (funcall #',turn-on))
-                     (funcall #',turn-on))))
-               (setq ,MODE-major-mode major-mode)))))
+         (let ((buffers ,MODE-buffers))
+           ;; Clear MODE-buffers to avoid scanning the same list of
+           ;; buffers in recursive calls to MODE-enable-in-buffers.
+           ;; Otherwise it could lead to infinite recursion.
+           (setq ,MODE-buffers nil)
+           (dolist (buf buffers)
+             (when (buffer-live-p buf)
+               (with-current-buffer buf
+                 (unless ,MODE-set-explicitly
+                   (unless (eq ,MODE-major-mode major-mode)
+                     (if ,mode
+                         (progn
+                           (,mode -1)
+                           (funcall #',turn-on))
+                       (funcall #',turn-on))))
+                 (setq ,MODE-major-mode major-mode))))))
        (put ',MODE-enable-in-buffers 'definition-name ',global-mode)
 
        (defun ,MODE-check-buffers ()
          (,MODE-enable-in-buffers)
-         (setq ,MODE-buffers nil)
          (remove-hook 'post-command-hook ',MODE-check-buffers))
        (put ',MODE-check-buffers 'definition-name ',global-mode)