bug#16170: Customizable log-edit commit messages

[Juri Linkov <juri@jurta.org>]

Currently the commit message is hard-coded that might be unsuitable
to other projects with different conventions.  This patch leaves the
current default unchanged, and moves it to a separate function,
so a set of messages could by easily configured in `log-edit-hook'.
Adding `save-excursion' to `log-edit-insert-cvs-template' was
necessary to not move point set by `message-position-point' in
`log-edit-insert-message-template'.

=== modified file 'lisp/vc/log-edit.el'
--- lisp/vc/log-edit.el	2013-12-04 00:37:33 +0000
+++ lisp/vc/log-edit.el	2013-12-17 00:34:35 +0000
@@ -126,12 +126,14 @@ (defcustom log-edit-setup-add-author nil
   :type 'boolean
   :safe 'booleanp)
 
-(defcustom log-edit-hook '(log-edit-insert-cvs-template
+(defcustom log-edit-hook '(log-edit-insert-message-template
+			   log-edit-insert-cvs-template
                            log-edit-show-files
 			   log-edit-insert-changelog)
   "Hook run at the end of `log-edit'."
   :group 'log-edit
-  :type '(hook :options (log-edit-insert-changelog
+  :type '(hook :options (log-edit-insert-message-template
+			 log-edit-insert-changelog
                          log-edit-insert-cvs-rcstemplate
                          log-edit-insert-cvs-template
 			 log-edit-insert-filenames)))
@@ -440,12 +442,6 @@ (defun log-edit (callback &optional setu
     (if mode
 	(funcall mode)
       (log-edit-mode))
-    (when setup
-      (erase-buffer)
-      (insert "Summary: ")
-      (when log-edit-setup-add-author
-        (insert "\nAuthor: "))
-      (insert "\n\n"))
     (set (make-local-variable 'log-edit-callback) callback)
     (if (listp params)
 	(dolist (crt params)
@@ -456,10 +452,9 @@ (defun log-edit (callback &optional setu
 
     (if buffer (set (make-local-variable 'log-edit-parent-buffer) parent))
     (set (make-local-variable 'log-edit-initial-files) (log-edit-files))
-    (when setup (run-hooks 'log-edit-hook))
-    (if setup
-        (message-position-point)
-      (goto-char (point-min)))
+    (when setup
+      (erase-buffer)
+      (run-hooks 'log-edit-hook))
     (push-mark (point-max))
     (message "%s" (substitute-command-keys
 	      "Press \\[log-edit-done] when you are done editing."))))
@@ -626,6 +621,17 @@ (defun log-edit-empty-buffer-p ()
                     (zerop (forward-line 1))))
         (eobp))))
 
+(defun log-edit-insert-message-template ()
+  "Insert the default template with Summary and Author."
+  (interactive)
+  (when (or (called-interactively-p 'interactive)
+            (log-edit-empty-buffer-p))
+    (insert "Summary: ")
+    (when log-edit-setup-add-author
+      (insert "\nAuthor: "))
+    (insert "\n\n")
+    (message-position-point)))
+
 (defun log-edit-insert-cvs-template ()
   "Insert the template specified by the CVS administrator, if any.
 This simply uses the local CVS/Template file."
@@ -701,6 +707,7 @@ (defun log-edit-insert-changelog (&optio
 or if the command is repeated a second time in a row, use the first log entry
 regardless of user name or time."
   (interactive "P")
+  (save-excursion
   (let ((eoh (save-excursion (rfc822-goto-eoh) (point))))
     (when (<= (point) eoh)
       (goto-char eoh)
@@ -732,8 +739,7 @@ (defun log-edit-insert-changelog (&optio
              (goto-char start)
              (skip-chars-forward "^():")
              (skip-chars-forward ": ")
-             (delete-region start (point)))))
-    (goto-char (point-min))))
+	       (delete-region start (point))))))))