From 2d6f319e497f89665c92f78076adcfa5963db64b Mon Sep 17 00:00:00 2001
From: szagi3891 <szeligagrzegorz@gmail.com>
Date: Tue, 14 Apr 2026 09:38:09 +0200
Subject: [PATCH] Guard Value::set while graph is refreshing

---
 .../vertigo/src/computed/dependencies/mod.rs   |  4 ++++
 .../computed/dependencies/transaction_state.rs |  5 +++++
 crates/vertigo/src/computed/value.rs           | 18 ++++++++++++++++--
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/crates/vertigo/src/computed/dependencies/mod.rs b/crates/vertigo/src/computed/dependencies/mod.rs
index 40c46324..6bb29d7a 100644
--- a/crates/vertigo/src/computed/dependencies/mod.rs
+++ b/crates/vertigo/src/computed/dependencies/mod.rs
@@ -40,6 +40,10 @@ pub fn get_dependencies() -> Rc<Dependencies> {
 }
 
 impl Dependencies {
+    pub(crate) fn is_refreshing(&self) -> bool {
+        self.transaction_state.is_refreshing()
+    }
+
     pub fn transaction<R, F: FnOnce(&Context) -> R>(&self, func: F) -> R {
         self.transaction_state.up();
 
diff --git a/crates/vertigo/src/computed/dependencies/transaction_state.rs b/crates/vertigo/src/computed/dependencies/transaction_state.rs
index 84e3b274..9d9bcb0d 100644
--- a/crates/vertigo/src/computed/dependencies/transaction_state.rs
+++ b/crates/vertigo/src/computed/dependencies/transaction_state.rs
@@ -25,6 +25,11 @@ impl TransactionState {
         }
     }
 
+    /// True while the graph is running client/computed refresh (after the outer transaction commits).
+    pub fn is_refreshing(&self) -> bool {
+        self.state.map(|state| matches!(state, State::Refreshing))
+    }
+
     pub fn up(&self) {
         let TransactionState { state } = self;
 
diff --git a/crates/vertigo/src/computed/value.rs b/crates/vertigo/src/computed/value.rs
index aab35356..afa3a418 100644
--- a/crates/vertigo/src/computed/value.rs
+++ b/crates/vertigo/src/computed/value.rs
@@ -108,7 +108,14 @@ impl<T: Clone + PartialEq + 'static> Value<T> {
     }
 
     pub fn change(&self, change_fn: impl FnOnce(&mut T)) {
-        get_dependencies().transaction(|ctx| {
+        let deps = get_dependencies();
+        if deps.is_refreshing() {
+            log::error!(
+                "Ignoring Value::change while the dependency graph is refreshing; the change was not applied"
+            );
+            return;
+        }
+        deps.transaction(|ctx| {
             let mut value = self.get(ctx);
             change_fn(&mut value);
             self.set(value);
@@ -116,7 +123,14 @@ impl<T: Clone + PartialEq + 'static> Value<T> {
     }
 
     pub fn set(&self, value: T) {
-        get_dependencies().transaction(|_| {
+        let deps = get_dependencies();
+        if deps.is_refreshing() {
+            log::error!(
+                "Ignoring Value::set while the dependency graph is refreshing (would corrupt scheduling); the write was not applied"
+            );
+            return;
+        }
+        deps.transaction(|_| {
             let need_refresh = self.inner.set(value);
             if need_refresh {
                 get_dependencies().report_set(self.inner.id);