Comment by jorelfermin

jdcasale you are right that Arc<RwLock<T>> is a code smell but I would take that a bit further that locking immutable data is even more of a smell. The real bad guy in this case is the RwLock not Arc. For anything that you hydrated once and never mutate you do not need the RwLock. Arc just clones the pointer so it is safe to share for concurrent reads so something like Arc<T> is fine and if you need initialization locking then LazyLock<Arc<T>> lets you lock the initialization but then everything else is just a pointer copy.

I hit this recently while building a url unfurl social card renderer for a project which ended up being something like LazyLock<Arc<Database>>