From b19a546c0ac639a5cf9e942fff7729ad30e91a5e Mon Sep 17 00:00:00 2001
From: Evan Almloff <evanalmloff@gmail.com>
Date: Fri, 22 Mar 2024 17:18:38 -0500
Subject: [PATCH] Don't move over event handler fields when diffing props
 (#2129)

* don't move over event handler fields when diffing props

* Expand values_memoize_in_place test to cover the new bug case
---
 packages/core-macro/src/props/mod.rs          | 23 +++++++++++++++----
 .../tests/values_memoize_in_place.rs          | 17 ++++++++++++--
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/packages/core-macro/src/props/mod.rs b/packages/core-macro/src/props/mod.rs
index f0aee564b..f0f8b7c8d 100644
--- a/packages/core-macro/src/props/mod.rs
+++ b/packages/core-macro/src/props/mod.rs
@@ -641,6 +641,15 @@ mod struct_info {
                 })
                 .collect();
 
+            let regular_fields: Vec<_> = self
+                .included_fields()
+                .filter(|f| !looks_like_signal_type(f.ty) && !looks_like_event_handler_type(f.ty))
+                .map(|f| {
+                    let name = f.name;
+                    quote!(#name)
+                })
+                .collect();
+
             let move_event_handlers = quote! {
                 #(
                     // Update the event handlers
@@ -668,9 +677,12 @@ mod struct_info {
                     // NOTE: we don't compare other fields individually because we want to let users opt-out of memoization for certain fields by implementing PartialEq themselves
                     let non_signal_fields_equal = self == new;
 
-                    // If they are not equal, we need to move over all the fields to self
+                    // If they are not equal, we need to move over all the fields that are not event handlers or signals to self
                     if !non_signal_fields_equal {
-                        *self = new.clone();
+                        let new_clone = new.clone();
+                        #(
+                            self.#regular_fields = new_clone.#regular_fields;
+                        )*
                     }
                     // Move any signal and event fields into their old container.
                     // We update signals and event handlers in place so that they are always up to date even if they were moved into a future in a previous render
@@ -684,9 +696,12 @@ mod struct_info {
                     let equal = self == new;
                     // Move any signal and event fields into their old container.
                     #move_event_handlers
-                    // If they are not equal, we need to move over all the fields to self
+                    // If they are not equal, we need to move over all the fields that are not event handlers to self
                     if !equal {
-                        *self = new.clone();
+                        let new_clone = new.clone();
+                        #(
+                            self.#regular_fields = new_clone.#regular_fields;
+                        )*
                     }
                     equal
                 })
diff --git a/packages/core-macro/tests/values_memoize_in_place.rs b/packages/core-macro/tests/values_memoize_in_place.rs
index 0aac11076..4e0e306ff 100644
--- a/packages/core-macro/tests/values_memoize_in_place.rs
+++ b/packages/core-macro/tests/values_memoize_in_place.rs
@@ -1,4 +1,6 @@
 use dioxus::prelude::*;
+use dioxus_core::ElementId;
+use std::rc::Rc;
 
 thread_local! {
     static DROP_COUNT: std::cell::RefCell<usize> = const { std::cell::RefCell::new(0) };
@@ -6,11 +8,19 @@ thread_local! {
 
 #[test]
 fn values_memoize_in_place() {
+    set_event_converter(Box::new(dioxus::html::SerializedHtmlEventConverter));
     let mut dom = VirtualDom::new(app);
 
-    dom.rebuild_in_place();
+    let mutations = dom.rebuild_to_vec();
+    println!("{:#?}", mutations);
     dom.mark_dirty(ScopeId::ROOT);
     for _ in 0..20 {
+        dom.handle_event(
+            "click",
+            Rc::new(PlatformEventData::new(Box::<SerializedMouseData>::default())),
+            ElementId(1),
+            true,
+        );
         dom.render_immediate(&mut dioxus_core::NoOpMutations);
     }
     dom.render_immediate(&mut dioxus_core::NoOpMutations);
@@ -57,7 +67,10 @@ fn TakesEventHandler(click: EventHandler<usize>, children: usize) -> Element {
     }
 
     rsx! {
-        button { "{children}" }
+        button {
+            onclick: move |_| click(children),
+            "{children}"
+        }
     }
 }