diff --git a/src/event.cpp b/src/event.cpp
index 3a208735c..05dc99492 100644
--- a/src/event.cpp
+++ b/src/event.cpp
@@ -291,7 +291,7 @@ void event_fire_delayed(parser_t &parser) {
     // Do not invoke new event handlers if we are unwinding (#6649).
     if (signal_check_cancel()) return;
 
-    std::vector<shared_ptr<event_t>> to_send;
+    std::vector<shared_ptr<const event_t>> to_send;
     to_send.swap(ld.blocked_events);
     assert(ld.blocked_events.empty());
 
diff --git a/src/parser.h b/src/parser.h
index 6c0a5e235..db42b69f4 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -186,7 +186,7 @@ struct library_data_t {
     const wchar_t *current_filename{};
 
     /// List of events that have been sent but have not yet been delivered because they are blocked.
-    std::vector<shared_ptr<event_t>> blocked_events{};
+    std::vector<shared_ptr<const event_t>> blocked_events{};
 
     /// A stack of fake values to be returned by builtin_commandline. This is used by the completion
     /// machinery when wrapping: e.g. if `tig` wraps `git` then git completions need to see git on