fix: disable lazy hydration when not using lazy-loading to avoid binary-size cost

examples/lazy_routes/Cargo.toml

@@ -10,7 +10,7 @@ crate-type = ["cdylib", "rlib"]
 axum = { version = "0.8.1", optional = true }
 console_error_panic_hook = "0.1.7"
 console_log = "1.0"
-leptos = { path = "../../leptos", features = ["tracing"] }
+leptos = { path = "../../leptos", features = ["tracing", "lazy"] }
 leptos_meta = { path = "../../meta" }
 leptos_axum = { path = "../../integrations/axum", optional = true }
 leptos_router = { path = "../../router" }

leptos/Cargo.toml

@@ -122,6 +122,7 @@ subsecond = [
   "web-sys/WebSocket",
   "web-sys/Window",
 ]
+lazy = ["tachys/lazy"]
 
 [dev-dependencies]
 tokio = { features = [

tachys/Cargo.toml

@@ -179,6 +179,7 @@ default = ["testing"]
 delegation = []                                                       # enables event delegation
 error-hook = []
 hydrate = []
+lazy = []
 islands = ["dep:serde", "dep:serde_json"]
 ssr = []
 oco = ["dep:oco_ref"]

tachys/src/view/any_view.rs

@@ -17,7 +17,7 @@ use crate::{
 };
 use futures::future::{join, join_all};
 use std::{any::TypeId, fmt::Debug};
-#[cfg(any(feature = "ssr", feature = "hydrate"))]
+#[cfg(any(feature = "ssr", all(feature = "hydrate", feature = "lazy")))]
 use std::{future::Future, pin::Pin};
 
 /// A type-erased view. This can be used if control flow requires that multiple different types of
@@ -67,10 +67,10 @@ pub struct AnyView {
     resolve: fn(Erased) -> Pin<Box<dyn Future<Output = AnyView> + Send>>,
     #[cfg(feature = "ssr")]
     dry_resolve: fn(&mut Erased),
-    #[cfg(feature = "hydrate")]
+    #[cfg(all(feature = "hydrate", not(feature = "lazy")))]
     #[allow(clippy::type_complexity)]
     hydrate_from_server: fn(Erased, &Cursor, &PositionState) -> AnyViewState,
-    #[cfg(feature = "hydrate")]
+    #[cfg(all(feature = "hydrate", feature = "lazy"))]
     #[allow(clippy::type_complexity)]
     hydrate_async: fn(
         Erased,
@@ -291,7 +291,7 @@ where
             }
         }
 
-        #[cfg(feature = "hydrate")]
+        #[cfg(all(feature = "hydrate", not(feature = "lazy")))]
         fn hydrate_from_server<T: RenderHtml + 'static>(
             value: Erased,
             cursor: &Cursor,
@@ -313,7 +313,7 @@ where
             }
         }
 
-        #[cfg(feature = "hydrate")]
+        #[cfg(all(feature = "hydrate", feature = "lazy"))]
         fn hydrate_async<T: RenderHtml + 'static>(
             value: Erased,
             cursor: &Cursor,
@@ -367,9 +367,9 @@ where
             to_html_async: to_html_async::<T::Owned>,
             #[cfg(feature = "ssr")]
             to_html_async_ooo: to_html_async_ooo::<T::Owned>,
-            #[cfg(feature = "hydrate")]
+            #[cfg(all(feature = "hydrate", not(feature = "lazy")))]
             hydrate_from_server: hydrate_from_server::<T::Owned>,
-            #[cfg(feature = "hydrate")]
+            #[cfg(all(feature = "hydrate", feature = "lazy"))]
             hydrate_async: hydrate_async::<T::Owned>,
             value: Erased::new(value),
         }
@@ -572,7 +572,7 @@ impl RenderHtml for AnyView {
         cursor: &Cursor,
         position: &PositionState,
     ) -> Self::State {
-        #[cfg(feature = "hydrate")]
+        #[cfg(all(feature = "hydrate", not(feature = "lazy")))]
         {
             if FROM_SERVER {
                 if cfg!(feature = "mark_branches") {
@@ -591,6 +591,14 @@ impl RenderHtml for AnyView {
                 );
             }
         }
+        #[cfg(all(feature = "hydrate", feature = "lazy"))]
+        {
+            use futures::FutureExt;
+
+            (self.hydrate_async)(self.value, cursor, position)
+                .now_or_never()
+                .unwrap()
+        }
         #[cfg(not(feature = "hydrate"))]
         {
             _ = cursor;
@@ -607,18 +615,28 @@ impl RenderHtml for AnyView {
         cursor: &Cursor,
         position: &PositionState,
     ) -> Self::State {
-        #[cfg(feature = "hydrate")]
+        #[cfg(all(feature = "hydrate", feature = "lazy"))]
         {
             if cfg!(feature = "mark_branches") {
                 cursor.advance_to_placeholder(position);
             }
+            #[cfg(all(feature = "hydrate", feature = "lazy"))]
             let state =
                 (self.hydrate_async)(self.value, cursor, position).await;
             if cfg!(feature = "mark_branches") {
                 cursor.advance_to_placeholder(position);
             }
             state
         }
+        #[cfg(all(feature = "hydrate", not(feature = "lazy")))]
+        {
+            _ = cursor;
+            _ = position;
+            panic!(
+                "the `lazy` feature on `tachys` must be activated to use lazy \
+                 hydration"
+            );
+        }
         #[cfg(not(feature = "hydrate"))]
         {
             _ = cursor;