Do not modify the buffer when KEYWORDS are unchanged

* ebuild-mode.el (ebuild-mode-put-keywords): Do not modify the
buffer unless there is an actual change.

Signed-off-by: Ulrich Müller <ulm@gentoo.org>

2 files changed, 8 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 625dca6..fbbb432 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2023-06-15  Ulrich Müller  <ulm@gentoo.org>
 
+	* ebuild-mode.el (ebuild-mode-put-keywords): Do not modify the
+	buffer unless there is an actual change.
+
 	* ebuild-mode-keywords.el (ebuild-mode-keywords-eclassdoc):
 	Renamed from ebuild-mode-keywords-eclass-documentation.
 	* ebuild-mode.el (ebuild-mode-font-lock-keywords): Update.
diff --git a/ebuild-mode.el b/ebuild-mode.el
index 77c6e9d..60d7e2c 100644
--- a/ebuild-mode.el
+++ b/ebuild-mode.el
@@ -620,16 +620,17 @@ Signal an error if this is not possible, or return nil if the
 optional second argument NOERROR is non-nil."
   (save-excursion
     (goto-char (point-min))
-    (let ((case-fold-search nil))
+    (let ((case-fold-search nil)
+	  (kw-string (mapconcat
+		      (lambda (e) (concat (cdr e) (car e))) kw " ")))
       (cond
        ((not (re-search-forward ebuild-mode-arch-regexp nil t))
 	(unless noerror (error "No KEYWORDS assignment found")))
        ((re-search-forward ebuild-mode-arch-regexp nil t)
 	(unless noerror (error "More than one KEYWORDS assignment found")))
        (t
-	(replace-match
-	 (mapconcat (lambda (e) (concat (cdr e) (car e))) kw " ")
-	 t t nil 1))))))
+	(unless (string-equal kw-string (match-string 1))
+	  (replace-match kw-string t t nil 1)))))))
 
 (defun ebuild-mode-modify-keywords (kw)
   "Set keywords. KW is an alist of architectures and leaders."