Prevent possible null pointer dereference

commands.c

@@ -160,11 +160,13 @@ cmd_info(girara_session_t* session, girara_list_t* UNUSED(argument_list))
   GString* string = g_string_new(NULL);
 
   GIRARA_LIST_FOREACH(information, zathura_document_information_entry_t*, iter, entry)
-    for (unsigned int i = 0; i < LENGTH(meta_fields); i++) {
-      if (meta_fields[i].field == entry->type) {
-        char* text = g_strdup_printf("<b>%s:</b> %s\n", meta_fields[i].name, entry->value);
-        g_string_append(string, text);
-        g_free(text);
+    if (entry != NULL) {
+      for (unsigned int i = 0; i < LENGTH(meta_fields); i++) {
+        if (meta_fields[i].field == entry->type) {
+          char* text = g_strdup_printf("<b>%s:</b> %s\n", meta_fields[i].name, entry->value);
+          g_string_append(string, text);
+          g_free(text);
+        }
       }
     }
   GIRARA_LIST_FOREACH_END(information, zathura_document_information_entry_t*, iter, entry);