Also, sending these ids via the form may be unnecessary if that information is already stored in your LiveView socket which is accessible in your event handlers e.g. def handle_event("alert", value, socket), do: ... end.
I was missing alot of knowledge. Now I see the problem was the field didn’t work as I thought, i.e. automatically. I ended up just going with html after all, since yes, the rest of the details are still on the socket.
These two are connected! On more recent versions of Phoenix, a core_components.ex file that implements <.input/> gets generated when creating a new app via mix phx.new my_app. That implementation uses pattern matching to automatically derive and add a :name and :value assign based on the :field assign. So if you want to use <.input/>, you’ll either need to manually add this file/function or implement it yourself.
It can be a bit confusing at first, especially since the LiveView library includes a standard default .form component, but doesn’t include a standard default .input component. That’s why the autogenerated core_components.ex file includes a .simple_form component that wraps the standard .form component as well as an .input component.