Assume the virtual dom is not rendering while not diffing components (#3406)

* Invert when the rendering flag is set

* Add a playwright test to make sure effects, and web-sys integration is working

* fix playwright test

packages/core/src/effect.rs

@@ -1,5 +1,4 @@
 use crate::innerlude::ScopeOrder;
-use crate::Runtime;
 use std::borrow::Borrow;
 use std::cell::RefCell;
 use std::collections::VecDeque;
@@ -29,13 +28,11 @@ impl Effect {
         self.effect.borrow_mut().push_back(Box::new(f));
     }
 
-    pub(crate) fn run(&self, runtime: &Runtime) {
-        runtime.rendering.set(false);
+    pub(crate) fn run(&self) {
         let mut effect = self.effect.borrow_mut();
         while let Some(f) = effect.pop_front() {
             f();
         }
-        runtime.rendering.set(true);
     }
 }
 

packages/core/src/runtime.rs

@@ -74,7 +74,7 @@ impl Runtime {
 
         Rc::new(Self {
             sender,
-            rendering: Cell::new(true),
+            rendering: Cell::new(false),
             scope_states: Default::default(),
             scope_stack: Default::default(),
             suspense_stack: Default::default(),
@@ -108,6 +108,14 @@ impl Runtime {
         }
     }
 
+    /// Run a closure with the rendering flag set to true
+    pub(crate) fn while_rendering<T>(&self, f: impl FnOnce() -> T) -> T {
+        self.rendering.set(true);
+        let result = f();
+        self.rendering.set(false);
+        result
+    }
+
     /// Create a scope context. This slab is synchronized with the scope slab.
     pub(crate) fn create_scope(&self, context: Scope) {
         let id = context.id;
@@ -380,9 +388,7 @@ impl Runtime {
             );
             for listener in listeners.into_iter().rev() {
                 if let AttributeValue::Listener(listener) = listener {
-                    self.rendering.set(false);
                     listener.call(uievent.clone());
-                    self.rendering.set(true);
                     let metadata = uievent.metadata.borrow();
 
                     if !metadata.propagates {
@@ -420,9 +426,7 @@ impl Runtime {
                 // Only call the listener if this is the exact target element.
                 if attr.name.get(2..) == Some(name) && target_path == this_path {
                     if let AttributeValue::Listener(listener) = &attr.value {
-                        self.rendering.set(false);
                         listener.call(uievent.clone());
-                        self.rendering.set(true);
                         break;
                     }
                 }

packages/core/src/tasks.rs

@@ -275,7 +275,6 @@ impl Runtime {
 
         // poll the future with the scope on the stack
         let poll_result = self.with_scope_on_stack(task.scope, || {
-            self.rendering.set(false);
             self.current_task.set(Some(id));
 
             let poll_result = task.task.borrow_mut().as_mut().poll(&mut cx);
@@ -293,7 +292,6 @@ impl Runtime {
 
             poll_result
         });
-        self.rendering.set(true);
         self.current_task.set(None);
 
         poll_result

packages/core/src/virtual_dom.rs

@@ -511,7 +511,7 @@ impl VirtualDom {
 
             // At this point, we have finished running all tasks that are pending and we haven't found any scopes to rerun. This means it is safe to run our lowest priority work: effects
             while let Some(effect) = self.pop_effect() {
-                effect.run(&self.runtime);
+                effect.run();
                 // Check if any new scopes are queued for rerun
                 self.queue_events();
                 if self.has_dirty_scopes() {
@@ -562,7 +562,10 @@ impl VirtualDom {
     #[instrument(skip(self, to), level = "trace", name = "VirtualDom::rebuild")]
     pub fn rebuild(&mut self, to: &mut impl WriteMutations) {
         let _runtime = RuntimeGuard::new(self.runtime.clone());
-        let new_nodes = self.run_scope(ScopeId::ROOT);
+        let new_nodes = self
+            .runtime
+            .clone()
+            .while_rendering(|| self.run_scope(ScopeId::ROOT));
 
         self.scopes[ScopeId::ROOT.0].last_rendered_node = Some(new_nodes.clone());
 
@@ -593,7 +596,9 @@ impl VirtualDom {
                 }
                 Work::RerunScope(scope) => {
                     // If the scope is dirty, run the scope and get the mutations
-                    self.run_and_diff_scope(Some(to), scope.id);
+                    self.runtime.clone().while_rendering(|| {
+                        self.run_and_diff_scope(Some(to), scope.id);
+                    });
                 }
             }
         }
@@ -700,7 +705,9 @@ impl VirtualDom {
                         .is_some();
                     if run_scope {
                         // If the scope is dirty, run the scope and get the mutations
-                        self.run_and_diff_scope(None::<&mut NoOpMutations>, scope_id);
+                        self.runtime.clone().while_rendering(|| {
+                            self.run_and_diff_scope(None::<&mut NoOpMutations>, scope_id);
+                        });
 
                         tracing::trace!("Ran scope {:?} during suspense", scope_id);
                     } else {