Subject: Archive Mode (arc-mode.el) not opening .zip files

From: binarydigitz01 <[email-masked]>
Date: Sun, 03 Aug 2025 09:52:17 +0000

I found a bug in arc-mode.el which makes it unable to open zip files, on
further analysis i found it was using incf instead of cl-incf. It is now
able to open .zip files and works as expected. I have attached a patch that fixes it.

In GNU Emacs 30.1.90 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
version 1.18.4, Xaw3d scroll bars)
Repository revision: emacs-30.1.90
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12401008
System Description: NixOS 25.11 (Xantusia)

Configured using:
 'configure
 --prefix=/nix/store/21npjyrbq3m495h63dsb7mj2kw69fg2z-emacs-unstable-30.1.90
 --disable-build-details --with-modules --with-x-toolkit=lucid
 --with-cairo --without-xft --with-compress-install
 --with-toolkit-scroll-bars --with-native-compilation
 --without-imagemagick --with-mailutils --without-small-ja-dic
 --with-tree-sitter --with-xinput2 --without-xwidgets --with-dbus
 --with-selinux'
diff --git a/lisp/arc-mode.el b/lisp/arc-mode.el
index 10ff3871074..1827d9d0ef5 100644
--- a/lisp/arc-mode.el
+++ b/lisp/arc-mode.el
@@ -1699,7 +1699,7 @@ archive--summarize-descs
                        (t (+ (string-width uid) (string-width gid) 1)))))
             (if (> len maxidlen) (setq maxidlen len))))
         (let ((size (archive--file-desc-size desc)))
-          (incf totalsize size)
+          (cl-incf totalsize size)
           (if (> size maxsize) (setq maxsize size))))
       (let* ((sizelen (length (number-to-string maxsize)))
              (dash