From f97fd557c32ebd5d2d385925494d2d37d8c450c1 Mon Sep 17 00:00:00 2001
From: Greg Johnston <greg.johnston@gmail.com>
Date: Sun, 21 Sep 2025 14:11:04 -0400
Subject: [PATCH] fix: maintain send/syncness of the handle

---
 tachys/src/html/event.rs          |  2 +-
 tachys/src/reactive_graph/bind.rs |  2 +-
 tachys/src/renderer/dom.rs        | 36 +++++++++++++++++--------------
 tachys/src/renderer/mod.rs        | 24 +++++++++++----------
 4 files changed, 35 insertions(+), 29 deletions(-)

diff --git a/tachys/src/html/event.rs b/tachys/src/html/event.rs
index f920beb20..8083b5e9f 100644
--- a/tachys/src/html/event.rs
+++ b/tachys/src/html/event.rs
@@ -324,7 +324,7 @@ where
         let (el, prev_cleanup) = state;
         if let Some(prev) = prev_cleanup.take() {
             if let Some(remove) = prev.into_inner() {
-                remove(el);
+                remove();
             }
         }
         *prev_cleanup = Some(if E::CAPTURE {
diff --git a/tachys/src/reactive_graph/bind.rs b/tachys/src/reactive_graph/bind.rs
index 60c973a05..7033ce9d1 100644
--- a/tachys/src/reactive_graph/bind.rs
+++ b/tachys/src/reactive_graph/bind.rs
@@ -259,7 +259,7 @@ where
 
         if let Some(prev) = prev_cleanup.take() {
             if let Some(remove) = prev.into_inner() {
-                remove(el);
+                remove();
             }
         }
         *prev_cleanup = Some(self.attach(el));
diff --git a/tachys/src/renderer/dom.rs b/tachys/src/renderer/dom.rs
index 658f5b533..37d8885e5 100644
--- a/tachys/src/renderer/dom.rs
+++ b/tachys/src/renderer/dom.rs
@@ -294,21 +294,22 @@ impl Dom {
         );
 
         // return the remover
-        RemoveEventHandler::new(el.clone(), {
+        RemoveEventHandler::new({
             let name = name.to_owned();
+            let el = el.clone();
             // safe to construct this here, because it will only run in the browser
             // so it will always be accessed or dropped from the main thread
-            let cb = send_wrapper::SendWrapper::new(cb);
-            move |el: &Element| {
+            let cb = send_wrapper::SendWrapper::new(move || {
                 or_debug!(
                     el.remove_event_listener_with_callback(
                         intern(&name),
                         cb.as_ref().unchecked_ref()
                     ),
-                    el,
+                    &el,
                     "removeEventListener"
                 )
-            }
+            });
+            move || cb()
         })
     }
 
@@ -332,22 +333,23 @@ impl Dom {
         );
 
         // return the remover
-        RemoveEventHandler::new(el.clone(), {
+        RemoveEventHandler::new({
             let name = name.to_owned();
+            let el = el.clone();
             // safe to construct this here, because it will only run in the browser
             // so it will always be accessed or dropped from the main thread
-            let cb = send_wrapper::SendWrapper::new(cb);
-            move |el: &Element| {
+            let cb = send_wrapper::SendWrapper::new(move || {
                 or_debug!(
                     el.remove_event_listener_with_callback_and_bool(
                         intern(&name),
                         cb.as_ref().unchecked_ref(),
                         true
                     ),
-                    el,
+                    &el,
                     "removeEventListener"
                 )
-            }
+            });
+            move || cb()
         })
     }
 
@@ -446,19 +448,21 @@ impl Dom {
         });
 
         // return the remover
-        RemoveEventHandler::new(el.clone(), {
+        RemoveEventHandler::new({
             let key = key.to_owned();
+            let el = el.clone();
             // safe to construct this here, because it will only run in the browser
             // so it will always be accessed or dropped from the main thread
-            let cb = send_wrapper::SendWrapper::new(cb);
-            move |el: &Element| {
-                drop(cb.take());
+            let el_cb = send_wrapper::SendWrapper::new((el, cb));
+            move || {
+                let (el, cb) = el_cb.take();
+                drop(cb);
                 or_debug!(
                     js_sys::Reflect::delete_property(
-                        el,
+                        &el,
                         &JsValue::from_str(&key)
                     ),
-                    el,
+                    &el,
                     "delete property"
                 );
             }
diff --git a/tachys/src/renderer/mod.rs b/tachys/src/renderer/mod.rs
index 6ea68cb96..da488116c 100644
--- a/tachys/src/renderer/mod.rs
+++ b/tachys/src/renderer/mod.rs
@@ -1,5 +1,5 @@
 use crate::view::{Mountable, ToTemplate};
-use std::{borrow::Cow, fmt::Debug};
+use std::{borrow::Cow, fmt::Debug, marker::PhantomData};
 use wasm_bindgen::JsValue;
 
 /// A DOM renderer.
@@ -121,29 +121,31 @@ pub trait Renderer: Send + Sized + Debug + 'static {
               later to avoid dropping it immediately, or leak it with \
               std::mem::forget() to never drop it."]
 #[allow(clippy::type_complexity)]
-pub struct RemoveEventHandler<T>(T, Option<Box<dyn FnOnce(&T) + Send + Sync>>);
+pub struct RemoveEventHandler<T>(
+    Option<Box<dyn FnOnce() + Send + Sync>>,
+    // only here to keep the generic, removing which would be a breaking change
+    // TODO remove generic in 0.9
+    PhantomData<fn() -> T>,
+);
 
 impl<T> RemoveEventHandler<T> {
     /// Creates a new container with a function that will be called when it is dropped.
-    pub(crate) fn new(
-        el: T,
-        remove: impl FnOnce(&T) + Send + Sync + 'static,
-    ) -> Self {
-        Self(el, Some(Box::new(remove)))
+    pub(crate) fn new(remove: impl FnOnce() + Send + Sync + 'static) -> Self {
+        Self(Some(Box::new(remove)), PhantomData)
     }
 
     #[allow(clippy::type_complexity)]
     pub(crate) fn into_inner(
         mut self,
-    ) -> Option<Box<dyn FnOnce(&T) + Send + Sync>> {
-        self.1.take()
+    ) -> Option<Box<dyn FnOnce() + Send + Sync>> {
+        self.0.take()
     }
 }
 
 impl<T> Drop for RemoveEventHandler<T> {
     fn drop(&mut self) {
-        if let Some(cb) = self.1.take() {
-            cb(&self.0)
+        if let Some(cb) = self.0.take() {
+            cb()
         }
     }
 }