fix: Use Rc for lifecycle management (#4471)

* fix: Use Rc for lifecycle management

* Try to unwrap the Rc instead of using both rc and option

* Add a test for use drop

* fix test name

---------

Co-authored-by: Evan Almloff <evanalmloff@gmail.com>

packages/core/src/global_context.rs

@@ -4,6 +4,7 @@ use crate::{
     Task,
 };
 use std::future::Future;
+use std::rc::Rc;
 use std::sync::Arc;
 
 /// Get the current scope id
@@ -441,15 +442,10 @@ pub fn use_drop<D: FnOnce() + 'static>(destroy: D) {
         }
     }
 
-    // We need to impl clone for the lifecycle, but we don't want the drop handler for the closure to be called twice.
-    impl<D: FnOnce()> Clone for LifeCycle<D> {
-        fn clone(&self) -> Self {
-            Self { ondestroy: None }
-        }
-    }
-
-    use_hook(|| LifeCycle {
-        ondestroy: Some(destroy),
+    use_hook(|| {
+        Rc::new(LifeCycle {
+            ondestroy: Some(destroy),
+        })
     });
 }
 

packages/core/tests/use_drop.rs

@@ -0,0 +1,67 @@
+//! Tests the use_drop hook
+use dioxus::dioxus_core::use_drop;
+use dioxus::prelude::*;
+use std::sync::{Arc, Mutex};
+
+type Shared<T> = Arc<Mutex<T>>;
+
+#[derive(Clone, Props)]
+struct AppProps {
+    render_child: Shared<bool>,
+    drop_count: Shared<u32>,
+}
+
+impl PartialEq for AppProps {
+    fn eq(&self, other: &Self) -> bool {
+        Arc::ptr_eq(&self.drop_count, &other.drop_count)
+    }
+}
+
+fn app(props: AppProps) -> Element {
+    let render_child = props.render_child.clone();
+    let render_child = *render_child.lock().unwrap();
+    println!(
+        "Rendering app component with render_child: {}",
+        render_child
+    );
+    rsx! {
+        if render_child {
+            child_component {
+                drop_count: props.drop_count.clone(),
+                render_child: props.render_child.clone()
+            }
+        }
+    }
+}
+
+fn child_component(props: AppProps) -> Element {
+    println!("Rendering child component");
+    use_drop(move || {
+        println!("Child component is being dropped");
+        let mut count = props.drop_count.lock().unwrap();
+        *count += 1;
+    });
+
+    rsx! {}
+}
+
+#[test]
+fn drop_runs() {
+    let drop_count = Arc::new(Mutex::new(0));
+    let render_child = Arc::new(Mutex::new(true));
+    let mut dom = VirtualDom::new_with_props(
+        app,
+        AppProps { drop_count: drop_count.clone(), render_child: render_child.clone() },
+    );
+
+    dom.rebuild_in_place();
+
+    assert_eq!(*drop_count.lock().unwrap(), 0);
+    *render_child.lock().unwrap() = false;
+
+    dom.mark_dirty(ScopeId::APP);
+    dom.render_immediate(&mut dioxus_core::NoOpMutations);
+
+    assert_eq!(*drop_count.lock().unwrap(), 1);
+    *render_child.lock().unwrap() = false;
+}