recover-this-file and accepting the autosave version, you'll have a modified buffer containing the autosave contents. At this point you can use M-x
diff-buffer-with-file RET to see the differences between the modified buffer and the saved file.
The key I've bound for this actually runs a custom function, in order to produce a unified diff, and to skip the prompt for the buffer (it assumes the current buffer).
(defun my-diff-buffer-with-file ()
"Compare the current modified buffer with the saved version."
(let ((diff-switches "-u")) ;; unified diff
There's also an ediff equivalent (which I generally prefer, although I do use both) which is available at M-x
If you wish to reject the modifications after checking the diff, you should be able to simply
undo the recovery. (Failing that you can always use
As keybindings for diff commands often involve =, I find the following convenient (n.b. I've unbound the default
C-z binding, and moved it instead to
C-z C-z, which opens up
C-z as a prefix for custom bindings):
(global-set-key (kbd "C-z =") 'my-diff-buffer-with-file)
(global-set-key (kbd "C-z C-=") 'ediff-current-file)