Don’t commit when there are no changes

Before trying to commit, run a ‘git diff’ to make sure there are any changes to
commit. If this turns up empty no commit is attempted.

NEWS

@@ -1,6 +1,12 @@
 # -*- mode: org; -*-
 #+STARTUP: showall
 
+* Unreleased
+
+  - Only try to commit when changes have been discovered in the file. By
+    extension git-auto-commit-mode won't ask for a summary to a commit that it
+    won't make.
+
 * v4.5.0
 
   - Support the fish shell through the ~gac-shell-and~ option.

git-auto-commit-mode.el

@@ -164,9 +164,19 @@ should already have been set up."
                             actual-buffer)
                gac--debounce-timers))))
 
+(defun gac--buffer-has-changes (buffer)
+  "Check to see if there is any change in BUFFER."
+  (let ((file-name (convert-standard-filename
+                    (file-name-nondirectory
+                     (buffer-file-name buffer)))))
+    (not (string=
+          (shell-command-to-string (concat "git diff " file-name))
+          ""))))
+
 (defun gac--after-save (buffer)
   (unwind-protect
-      (when (buffer-live-p buffer)
+      (when (and (buffer-live-p buffer)
+                 (gac--buffer-has-changes buffer))
         (gac-commit buffer)
         (with-current-buffer buffer
           ;; with-current-buffer required here because gac-automatically-push-p