only subscribe scopes to signals when rendering

packages/signals/src/copy_value.rs

@@ -86,8 +86,12 @@ fn current_owner<S: Storage<T>, T>() -> Owner<S> {
     }
 
     // Otherwise get the owner from the current reactive context.
-    let current_reactive_context = ReactiveContext::current();
-    owner_in_scope(current_reactive_context.origin_scope())
+    match ReactiveContext::current(){
+        Some(current_reactive_context) => owner_in_scope(current_reactive_context.origin_scope()),
+        None => {
+            owner_in_scope(current_scope_id().expect("in a virtual dom"))
+        }
+    }
 }
 
 fn owner_in_scope<S: Storage<T>, T>(scope: ScopeId) -> Owner<S> {

packages/signals/src/global/memo.rs

@@ -33,7 +33,7 @@ impl<T: PartialEq + 'static> GlobalMemo<T> {
             None => {
                 drop(read);
                 // Constructors are always run in the root scope
-                let signal = ScopeId::ROOT.in_runtime(|| Signal::selector(self.selector));
+                let signal = ScopeId::ROOT.in_runtime(|| Signal::memo(self.selector));
                 context.signal.borrow_mut().insert(key, Box::new(signal));
                 signal
             }

packages/signals/src/reactive_context.rs

@@ -1,5 +1,5 @@
 use dioxus_core::prelude::{
-    current_scope_id, has_context, provide_context, schedule_update_any, ScopeId,
+    current_scope_id, has_context, provide_context, schedule_update_any, ScopeId
 };
 use generational_box::SyncStorage;
 use rustc_hash::FxHashSet;
@@ -68,21 +68,24 @@ impl ReactiveContext {
     /// If this was set manually, then that value will be returned.
     ///
     /// If there's no current reactive context, then a new one will be created for the current scope and returned.
-    pub fn current() -> Self {
+    pub fn current() -> Option<Self> {
         let cur = CURRENT.with(|current| current.borrow().last().cloned());
 
         // If we're already inside a reactive context, then return that
         if let Some(cur) = cur {
-            return cur;
+            return Some(cur);
         }
 
         // If we're rendering, then try and use the reactive context attached to this component
+        if !dioxus_core::vdom_is_rendering(){
+            return None;
+        }
         if let Some(cx) = has_context() {
-            return cx;
+            return Some(cx);
         }
 
         // Otherwise, create a new context at the current scope
-        provide_context(ReactiveContext::new_for_scope(current_scope_id()))
+        Some(provide_context(ReactiveContext::new_for_scope(current_scope_id())))
     }
 
     /// Run this function in the context of this reactive context

packages/signals/src/signal.rs

@@ -90,19 +90,19 @@ impl<T: PartialEq + 'static> Signal<T> {
     ///
     /// Selectors can be used to efficiently compute derived data from signals.
     #[track_caller]
-    pub fn selector(f: impl FnMut() -> T + 'static) -> ReadOnlySignal<T> {
-        Self::maybe_sync_memo(f)
+    pub fn memo(f: impl FnMut() -> T + 'static) -> ReadOnlySignal<T> {
+        Self::use_maybe_sync_memo(f)
     }
 
     /// Creates a new Selector that may be Sync + Send. The selector will be run immediately and whenever any signal it reads changes.
     ///
     /// Selectors can be used to efficiently compute derived data from signals.
     #[track_caller]
-    pub fn maybe_sync_memo<S: Storage<SignalData<T>>>(
+    pub fn use_maybe_sync_memo<S: Storage<SignalData<T>>>(
         mut f: impl FnMut() -> T + 'static,
     ) -> ReadOnlySignal<T, S> {
         // Get the current reactive context
-        let rc = ReactiveContext::current();
+        let rc = ReactiveContext::new();
 
         // Create a new signal in that context, wiring up its dependencies and subscribers
         let mut state: Signal<T, S> = rc.run_in(|| Signal::new_maybe_sync(f()));
@@ -201,8 +201,9 @@ impl<T, S: Storage<SignalData<T>>> Readable for Signal<T, S> {
     fn try_read(&self) -> Result<ReadableRef<Self>, generational_box::BorrowError> {
         let inner = self.inner.try_read()?;
 
-        let reactive_context = ReactiveContext::current();
-        inner.subscribers.lock().unwrap().insert(reactive_context);
+        if let Some(reactive_context) = ReactiveContext::current(){
+            inner.subscribers.lock().unwrap().insert(reactive_context);
+        }
 
         Ok(S::map(inner, |v| &v.value))
     }