- as per the diff-hl-mode README
If you're using a version before 2.4.0, it defines
magit-revert-buffer-hook (or magit-not-reverted-hook),
which we use.
When using Magit 2.4 or newer, add this to your init script:
(add-hook 'magit-post-refresh-hook 'diff-hl-magit-post-refresh)