Only use Gnus registry for formatting when registry is loaded

See bug #36903

* lisp/gnus/gnus-registry.el (gnus-registry-article-marks-to-chars):
  (gnus-registry-article-marks-to-names): In some circumstances it's
  possible for the user's summary line format spec to include
  registry-specific code, while the registry itself isn't actually
  loaded. Make sure the database is actually a hashtable before
  accessing it.

1 files changed, 16 insertions, 12 deletions

diff --git a/lisp/gnus/gnus-registry.el b/lisp/gnus/gnus-registry.el
index e949179b3cc..ff0d4bad715 100644
--- a/lisp/gnus/gnus-registry.el
+++ b/lisp/gnus/gnus-registry.el
@@ -1007,23 +1007,27 @@ Uses `gnus-registry-marks' to find what shortcuts to install."
 ;; (defalias 'gnus-user-format-function-M 'gnus-registry-article-marks-to-chars)
 (defun gnus-registry-article-marks-to-chars (headers)
   "Show the marks for an article by the :char property."
-  (let* ((id (mail-header-message-id headers))
-         (marks (when id (gnus-registry-get-id-key id 'mark))))
-    (concat (delq nil
-                  (mapcar
-                   (lambda (m)
-                     (plist-get
-                      (cdr-safe (assoc m gnus-registry-marks))
-                      :char))
-                   marks)))))
+  (if (hash-table-p gnus-registry-db)
+      (let* ((id (mail-header-message-id headers))
+             (marks (when id (gnus-registry-get-id-key id 'mark))))
+        (concat (delq nil
+                      (mapcar
+                       (lambda (m)
+                         (plist-get
+                          (cdr-safe (assoc m gnus-registry-marks))
+                          :char))
+                       marks))))
+    ""))
 
 ;; use like this:
 ;; (defalias 'gnus-user-format-function-M 'gnus-registry-article-marks-to-names)
 (defun gnus-registry-article-marks-to-names (headers)
   "Show the marks for an article by name."
-  (let* ((id (mail-header-message-id headers))
-         (marks (when id (gnus-registry-get-id-key id 'mark))))
-    (mapconcat (lambda (mark) (symbol-name mark)) marks ",")))
+  (if (hash-table-p gnus-registry-db)
+      (let* ((id (mail-header-message-id headers))
+             (marks (when id (gnus-registry-get-id-key id 'mark))))
+        (mapconcat (lambda (mark) (symbol-name mark)) marks ","))
+    ""))
 
 (defun gnus-registry-read-mark ()
   "Read a mark name from the user with completion."