Why the diff order reverse?

[snowman]

Description

By debug suffixes data of function backup-walker-refresh, its structure is (".~3~" ".~2~" ".~1~")

Every time you

1. press "p" (prev changes) to increase(+) index pointer, like from ".~3~" to ".~2~" (for older changes)
2. press "n" (next changes) to decrease(-) index pointer, like from ".~2~" to ".~3~" (for newer changes)

The first item ".~3~" is most recent, this is different from git notation like HEAD~3

So in your code, left-file with (setq left-file (concat prefix (nth (1- index) suffixes))) means more recent file, right-file means older file

But you passed them to function diff-no-select in reversed order

backup-walker/backup-walker.el

Lines 269 to 274 in 934a412

	(if (eq index 0)
	(setq left-file (cdr (assq :original-file backup-walker-data-alist))
	left-version "orig")
	(setq left-file (concat prefix (nth (1- index) suffixes))
	left-version (format "%i" (backup-walker-get-version left-file))))
	(setq diff-buf (diff-no-select left-file right-file nil 'noasync))

---

see? you write (diff old new switches no-async)

backup-walker/backup-walker.el

Lines 120 to 123 in 934a412

	(or (fboundp 'diff-no-select)
	(defun diff-no-select (old new &optional switches no-async)
	(save-window-excursion (diff old new switches no-async))
	(get-buffer-create "*Diff*")))

---

What you expect?

(setq diff-buf (diff-no-select left-file right-file nil 'noasync))

should be

(setq diff-buf (diff-no-select right-file left-file nil 'noasync))