Don't crash when listing shared namespace prefix.

--HG--
branch : HEAD

diff --git a/src/lib-storage/mailbox-list.c b/src/lib-storage/mailbox-list.c
index fa2bc8c69b8e9f74badd9cd93314b9fe7f5bd23e..150b8bb07c87d1f7da613c1208bb67d80ac1c04c 100644 (file)
--- a/src/lib-storage/mailbox-list.c
+++ b/src/lib-storage/mailbox-list.c
@@ -679,9 +679,10 @@ int mailbox_list_mailbox(struct mailbox_list *list, const char *name,
 
        *flags_r = 0;
        path = mailbox_list_get_path(list, name, MAILBOX_LIST_PATH_TYPE_DIR);
-       return list->v.iter_is_mailbox(&ctx, path, "", "",
-                                      MAILBOX_LIST_FILE_TYPE_UNKNOWN,
-                                      flags_r);
+       return list->v.iter_is_mailbox == NULL ? 0 :
+               list->v.iter_is_mailbox(&ctx, path, "", "",
+                                       MAILBOX_LIST_FILE_TYPE_UNKNOWN,
+                                       flags_r);
 }
 
 void mailbox_list_add_change(struct mailbox_list *list,