commit 2964fa126a059bb6f610c43fd8bcf1e700a3f107
Author: Campbell Barton <ideasman42@gmail.com>
Date:   Mon Nov 8 16:33:39 2021 +1100

    Add 'with-undo-amalgamate' macro

    This allows commands to be made without adding undo-barriers, e.g.
    kmacro-exec-ring-item.

diff --git a/lisp/subr.el b/lisp/subr.el
index f6dbd00532..73b799c65b 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -3542,6 +3542,29 @@ atomic-change-group
 	     (accept-change-group ,handle)
 	   (cancel-change-group ,handle))))))

+(defmacro with-undo-amalgamate (&rest body)
+  "Like `progn' but perform BODY with amalgamated undo barriers.
+
+This allows multiple operations to be undone in a single step.
+When undo is disabled this behaves like `progn'."
+  (declare (indent 0) (debug t))
+  (let ((handle (make-symbol "--change-group-handle--")))
+    `(let ((,handle (prepare-change-group))
+           ;; Don't truncate any undo data in the middle of this.
+           ;; This guarantees the resulting undo step is complete,
+           ;; so the user can't undo into an intermediate step
+           ;; performed within the body of this macro.
+           (undo-outer-limit nil)
+           (undo-limit most-positive-fixnum)
+           (undo-strong-limit most-positive-fixnum))
+       (unwind-protect
+           (progn
+             (activate-change-group ,handle)
+             ,@body)
+         (progn
+           (accept-change-group ,handle)
+           (undo-amalgamate-change-group ,handle))))))
+
 (defun prepare-change-group (&optional buffer)
   "Return a handle for the current buffer's state, for a change group.
 If you specify BUFFER, make a handle for BUFFER's state instead.