About

diff-hl-mode highlights uncommitted changes on the left side of the window,
allows you to jump between and revert them selectively.

For the usage instructions and the list of commands, see the Commentary section
inside the file.

Tested with Git, Mercurial, Bazaar and SVN. May work with other VC backends, too.

The package also contains auxiliary modes:

• diff-hl-dired-mode provides similar functionality in Dired.
• diff-hl-margin-mode changes the highlighting function to
  use the margin instead of the fringe.
• diff-hl-amend-mode shifts the reference revision back by one.
• diff-hl-flydiff-mode implements highlighting changes on the fly.
  It requires Emacs 24.4 or newer.

Check out the Commentary section in each respective file for the usage
instructions.

Screenshots

diff-hl-mode

Top window: a buffer in this minor mode, bottom window: the corresponding diff.

diff-hl-dired-mode

diff-hl-margin-mode

Requirements

Emacs 24.3+.

Notes

• By default diff-hl-mode uses the corresponding VC diff command, so
  it's only accurate when the buffer is in saved state. Check out
  diff-hl-flydiff-mode, it aims to handle unsaved buffers as well.

• To use an
  alternative diff algorithm
  with Git, add a corresponding argument to vc-git-diff-switches,
  e.g. (setq vc-git-diff-switches '("--histogram")). Using the
  diff.algorithm option doesn't work
  because
  vc-git-diff calls git diff-index. diff-hl-flydiff-mode does
  not support alternative algorithms, because it uses the external
  diff program.

• We conflict with other modes when they put indicators on the fringe,
  such as Flycheck. This is
  rarely a significant problem, since if you're using such a mode,
  you'd usually want to fix all errors and warnings before continuing,
  and then the conflicting indicators go away.

• There's no fringe when Emacs is running in the console, but the navigation
  and revert commands still work. Consider turning diff-hl-margin-mode on,
  to show the indicators in the margin instead.

• Frame-local and buffer-local values of line-spacing are not supported.

• Fringe width up to 16 works best (because we can't define a bitmap
  with width above that number).

• emacs-git-gutter shows
  indicators in the margin by default, allows you to customize how the
  indicators look more easily, and has a "stage hunk" command.

Integration

If you're using some package other than vc to commit changes, it might
not run vc-checkin-hook after commits. In that case, you'll need to
either add diff-hl-update to the hook it does run, or advise some
function that's called in the buffer after its state has changed.

psvn

(defadvice svn-status-update-modeline (after svn-update-diff-hl activate)
  (diff-hl-update))

Magit

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)