; Handle edge-case when deleting the last package

* lisp/emacs-lisp/package.el (package-delete): Rebind 'package-alist'
while calling 'package--used-elsewhere-p'.  (bug#65475)

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 0140a565e3ba6a871e6727acb77d1d5a467d4bc0..5a508882dc3b224f0c55e520258512c91c8a74a5 100644 (file)
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -2521,8 +2521,12 @@ If NOSAVE is non-nil, the package is not removed from
                                            nil t)))
        (list (cdr (assoc package-name package-table))
              current-prefix-arg nil))))
-  (let ((dir (package-desc-dir pkg-desc))
-        (name (package-desc-name pkg-desc))
+  (let* ((dir (package-desc-dir pkg-desc))
+         (name (package-desc-name pkg-desc))
+         (new-package-alist (let ((pkgs (assq name package-alist)))
+                              (if (null (remove pkg-desc (cdr pkgs)))
+                                  (remq pkgs package-alist)
+                                package-alist)))
         pkg-used-elsewhere-by)
     ;; If the user is trying to delete this package, they definitely
     ;; don't want it marked as selected, so we remove it from
@@ -2541,7 +2545,8 @@ If NOSAVE is non-nil, the package is not removed from
                   (package-desc-full-name pkg-desc)))
           ((and (null force)
                 (setq pkg-used-elsewhere-by
-                      (package--used-elsewhere-p pkg-desc)))
+                      (let ((package-alist new-package-alist))
+                        (package--used-elsewhere-p pkg-desc)))) ;See bug#65475
            ;; Don't delete packages used as dependency elsewhere.
            (error "Package `%s' is used by `%s' as dependency, not deleting"
                   (package-desc-full-name pkg-desc)
@@ -2562,10 +2567,7 @@ If NOSAVE is non-nil, the package is not removed from
                (when (file-exists-p file)
                  (delete-file file))))
            ;; Update package-alist.
-           (let ((pkgs (assq name package-alist)))
-             (delete pkg-desc pkgs)
-             (unless (cdr pkgs)
-               (setq package-alist (delq pkgs package-alist))))
+           (setq package-alist new-package-alist)
            (package--quickstart-maybe-refresh)
            (message "Package `%s' deleted."
                     (package-desc-full-name pkg-desc))))))