Subject: bug#78636: 30.1; package-install-file errors with some tar files

From: Andy Rosen <[email-masked]>
Date: Thu, 29 May 2025 15:56:31 +0000

Running 'package-install-file' on a tar file might throw a 'Wrong type argument: arrayp, nil' error from 'tar--check-descriptor’.  The problem comes from assumptions made by 'package--description-file' and tar-mode about the filenames contained in the tar file.  I’ve written a detailed description of the error and root cause here <https://github.com/ajrosen/bookmarks-menu/discussions/2> .

I propose adding a 'condition-case' to 'package-install-file' to return a friendly message.

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 82fcf439a11..01f659e6982 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -2439,8 +2439,10 @@ directory."
       (insert-file-contents-literally file)
       (set-visited-file-name file)
       (set-buffer-modified-p nil)
-      (when (string-match "\\.tar\\'" file) (tar-mode)))

-    (package-install-from-buffer)))
+      (when (string-match "\\.tar\\'" file) (tar-mode)
+            (condition-case nil
+                (package-install-from-buffer)
+      (error (message "%s is not a valid package file" (file-name-nondirectory file))))))))
  ;;;###autoload
 (defun package-install-selected-packages (&optional noconfirm)

In GNU Emacs 30.1 (build 1, aarch64-apple-darwin21.6.0, NS
 appkit-2113.65 Version 12.7.6 (Build 21H1320)) of 2025-02-24 built on
 armbob.lan
Windowing system distributor 'Apple', version 10.3.2575
System Description:  macOS 15.5

Configured using:
 'configure --with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp' --with-modules 'CFLAGS=-DFD_SETSIZE=10000
 -DDARWIN_UNLIMITED_SELECT' --with-x-toolkit=no'

Configured features:
ACL GLIB GMP GNUTLS JPEG LIBXML2 MODULES NOTIFY KQUEUE NS PDUMPER PNG
RSVG SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XIM ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  minibuffer-regexp-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068

epg-config gnus-util text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
cl-loaddefs cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils rmc iso-transl tooltip cconv eldoc paren electric
uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
term/ns-win ns-win ucs-normalize mule-util term/common-win tool-bar dnd
fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow

isearch easymenu timer select scroll-bar mouse jit-lock font-lock syntax

font-core term/tty-colors frame minibuffer nadvice seq simple cl-generic

indonesian philippine cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
composite emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads kqueue cocoa ns multi-tty
make-network-process emacs)

Memory information:
((conses 16 39125 8959) (symbols 48 5269 0) (strings 32 12063 2290)
 (string-bytes 1 290705) (vectors 16 9393)
 (vector-slots 8 106790 6658) (floats 8 21 8) (intervals 56 253 5)
 (buffers 992 11))