Fix: Hydratation of empty lists next to components. (#3630)

* fix: hydration of empty VLists

an additional (empty) VText was inserted in the second reconciliation
pass, which tried to insert itself in an invalid position. This internal
error was masked by a "fix" of the internal slot of components, which
should have still been trapped to signal that the second fixup render
was not yet run.

* fixup: new lints from clippy

Cargo.lock

@@ -2112,6 +2112,16 @@ dependencies = [
  "yew",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.15"
@@ -2197,6 +2207,12 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "papergrid"
 version = "0.10.0"
@@ -2771,6 +2787,15 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "signal-hook-registry"
 version = "1.4.1"
@@ -2787,14 +2812,14 @@ dependencies = [
  "bytes",
  "clap",
  "futures 0.3.29",
- "log",
  "reqwest",
  "serde",
+ "time",
  "tokio",
+ "tracing-subscriber",
+ "tracing-web",
  "uuid",
  "warp",
- "wasm-bindgen-futures",
- "wasm-logger",
  "yew",
 ]
 
@@ -3033,6 +3058,16 @@ dependencies = [
  "syn 2.0.38",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b9ef9bad013ada3808854ceac7b46812a6465ba368859a37e2100283d2d719c"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+]
+
 [[package]]
 name = "time"
 version = "0.3.30"
@@ -3040,6 +3075,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c4a34ab300f2dee6e562c10a046fc05e358b29f9bf92277f30c3c8d82275f6f5"
 dependencies = [
  "deranged",
+ "js-sys",
  "powerfmt",
  "serde",
  "time-core",
@@ -3274,6 +3310,45 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c06d3da6113f116aaee68e4d601191614c9053067f9ab7f6edbcb161237daa54"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad0f048c97dbd9faa9b7df56362b8ebcaa52adb06b498c050d2f4e32f90a7a8b"
+dependencies = [
+ "nu-ansi-term",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing-core",
+ "tracing-log",
+]
+
+[[package]]
+name = "tracing-web"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e6a141feebd51f8d91ebfd785af50fca223c570b86852166caa3b141defe7c"
+dependencies = [
+ "js-sys",
+ "tracing-core",
+ "tracing-subscriber",
+ "wasm-bindgen",
+ "web-sys",
 ]
 
 [[package]]
@@ -3410,6 +3485,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"

packages/yew/src/callback.rs

@@ -25,7 +25,9 @@ macro_rules! generate_callback_impls {
             }
         }
 
-        #[allow(clippy::vtable_address_comparisons)]
+        // We are okay with comparisons from different compilation units to result in false
+        // not-equal results. This should only lead in the worst-case to some unneeded re-renders.
+        #[allow(ambiguous_wide_pointer_comparisons)]
         impl<IN, OUT> PartialEq for $callback<IN, OUT> {
             fn eq(&self, other: &$callback<IN, OUT>) -> bool {
                 let ($callback { cb }, $callback { cb: rhs_cb }) = (self, other);

packages/yew/src/dom_bundle/blist.rs

@@ -11,7 +11,7 @@ use super::{test_log, BNode, BSubtree, DomSlot};
 use crate::dom_bundle::{Reconcilable, ReconcileTarget};
 use crate::html::AnyScope;
 use crate::utils::RcExt;
-use crate::virtual_dom::{Key, VList, VNode, VText};
+use crate::virtual_dom::{Key, VList, VNode};
 
 /// This struct represents a mounted [VList]
 #[derive(Debug)]
@@ -427,15 +427,7 @@ impl Reconcilable for VList {
         // The left items are known since we want to insert them
         // (self.children). For the right ones, we will look at the bundle,
         // i.e. the current DOM list element that we want to replace with self.
-        let (key, mut fully_keyed, mut lefts) = self.split_for_blist();
+        let (key, fully_keyed, lefts) = self.split_for_blist();
-
-        if lefts.is_empty() {
-            // Without a placeholder the next element becomes first
-            // and corrupts the order of rendering
-            // We use empty text element to stake out a place
-            lefts.push(VText::new("").into());
-            fully_keyed = false;
-        }
 
         let rights = &mut blist.rev_children;
         test_log!("lefts: {:?}", lefts);

packages/yew/src/dom_bundle/utils.rs

@@ -50,6 +50,10 @@ mod feat_hydration {
 
 #[cfg(feature = "hydration")]
 pub(super) use feat_hydration::*;
+#[cfg(test)]
+// this is needed because clippy doesn't like the import not being used
+#[allow(unused_imports)]
+pub(super) use tests::*;
 
 #[cfg(test)]
 mod tests {
@@ -87,8 +91,3 @@ mod tests {
         (root, scope, parent, sibling)
     }
 }
-
-#[cfg(test)]
-// this is needed because clippy doesn't like the import not being used
-#[allow(unused_imports)]
-pub(super) use tests::*;

packages/yew/src/functional/hooks/use_reducer.rs

@@ -130,7 +130,10 @@ where
     T: Reducible,
 {
     fn eq(&self, rhs: &Self) -> bool {
-        #[allow(clippy::vtable_address_comparisons)]
+        // We are okay with comparisons from different compilation units to result in false
+        // not-equal results. This should only lead in the worst-case to some unneeded
+        // re-renders.
+        #[allow(ambiguous_wide_pointer_comparisons)]
         Rc::ptr_eq(&self.dispatch, &rhs.dispatch)
     }
 }

packages/yew/src/html/component/lifecycle.rs

@@ -430,7 +430,9 @@ impl ComponentState {
         fields(component.id = self.comp_id)
     )]
     fn render(&mut self, shared_state: &Shared<Option<ComponentState>>) {
-        match self.inner.view() {
+        let view = self.inner.view();
+        tracing::trace!(?view, "render result");
+        match view {
             Ok(vnode) => self.commit_render(shared_state, vnode),
             Err(RenderError::Suspended(susp)) => self.suspend(shared_state, susp),
         };

packages/yew/src/html/component/scope.rs

@@ -642,7 +642,7 @@ mod feat_hydration {
     use web_sys::{Element, HtmlScriptElement};
 
     use super::*;
-    use crate::dom_bundle::{BSubtree, DomSlot, DynamicDomSlot, Fragment};
+    use crate::dom_bundle::{BSubtree, DynamicDomSlot, Fragment};
     use crate::html::component::lifecycle::{ComponentRenderState, CreateRunner, RenderRunner};
     use crate::scheduler;
     use crate::virtual_dom::Collectable;
@@ -679,12 +679,6 @@ mod feat_hydration {
             let collectable = Collectable::for_component::<COMP>();
 
             let mut fragment = Fragment::collect_between(fragment, &collectable, &parent);
-            let next_sibling = if let Some(n) = fragment.front() {
-                Some(n.clone())
-            } else {
-                fragment.sibling_at_end().cloned()
-            };
-            internal_ref.reassign(DomSlot::create(next_sibling));
 
             let prepared_state = match fragment
                 .back()

packages/yew/src/suspense/suspension.rs

@@ -105,7 +105,7 @@ impl Future for Suspension {
 
         let waker = cx.waker().clone();
         self.listen(Callback::from(move |_| {
-            waker.clone().wake();
+            waker.wake_by_ref();
         }));
 
         Poll::Pending

packages/yew/src/virtual_dom/listeners.rs

@@ -187,9 +187,11 @@ impl PartialEq for Listeners {
                     lhs.iter()
                         .zip(rhs.iter())
                         .all(|(lhs, rhs)| match (lhs, rhs) {
-                            (Some(lhs), Some(rhs)) =>
+                            (Some(lhs), Some(rhs)) => {
-                            {
+                                // We are okay with comparisons from different compilation units to
-                                #[allow(clippy::vtable_address_comparisons)]
+                                // result in false not-equal results. This should only lead in the
+                                // worst-case to some unneeded re-renders.
+                                #[allow(ambiguous_wide_pointer_comparisons)]
                                 Rc::ptr_eq(lhs, rhs)
                             }
                             (None, None) => true,