Hash and compare templates by value in debug mode (#3630)

* Hash and compare templates by value in debug mode

* add a regression test for layout state persisting after navigation

* More reliable static item merged detection

packages/router/tests/via_ssr/main.rs

@@ -1,4 +1,5 @@
 mod link;
+mod navigation;
 mod outlet;
 mod redirect;
 mod without_index;

packages/router/tests/via_ssr/navigation.rs

@@ -0,0 +1,69 @@
+use dioxus::prelude::*;
+use dioxus_core::NoOpMutations;
+use std::sync::atomic::AtomicUsize;
+
+// Regression test for <https://github.com/DioxusLabs/dioxus/issues/3235>
+#[test]
+fn layout_retains_state_after_navigation() {
+    let mut vdom = VirtualDom::new(app);
+    vdom.rebuild_in_place();
+
+    vdom.render_immediate(&mut NoOpMutations);
+    let as_string = dioxus_ssr::render(&vdom);
+    assert_eq!(as_string, "Other");
+}
+
+fn app() -> Element {
+    rsx! {
+        Router::<Route> {}
+    }
+}
+
+// Turn off rustfmt since we're doing layouts and routes in the same enum
+#[derive(Routable, Clone, Debug, PartialEq)]
+#[rustfmt::skip]
+enum Route {
+    // Wrap Home in a Navbar Layout
+    #[layout(NavBar)]
+        // The default route is always "/" unless otherwise specified
+        #[route("/")]
+        Home {},
+            
+        #[route("/other")]
+        Other {},
+}
+
+#[component]
+fn NavBar() -> Element {
+    static NAVBARS_CREATED: AtomicUsize = AtomicUsize::new(0);
+    use_hook(|| {
+        let navbars_created = NAVBARS_CREATED.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+        println!("creating navbar #{navbars_created}");
+        if navbars_created > 0 {
+            panic!("layouts should not be recreated when switching between two routes under the nav bar");
+        }
+    });
+
+    // Queue an effect to navigate to the other route after rebuild_in_place
+    use_effect(|| {
+        router().push(Route::Other {});
+    });
+
+    rsx! {
+        Outlet::<Route> {}
+    }
+}
+
+#[component]
+fn Home() -> Element {
+    rsx! {
+        "Home!"
+    }
+}
+
+#[component]
+fn Other() -> Element {
+    rsx! {
+        "Other"
+    }
+}