From e3d69b537204720601e2a4d23147f64f399e09e4 Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <trueadm@users.noreply.github.com>
Date: Mon, 10 Feb 2025 12:14:17 +0000
Subject: [PATCH] fix: when an unowned derived is tracked again, remove unowned
 flag

---
 .changeset/nasty-pigs-lay.md                  |  5 +++++
 .../svelte/src/internal/client/runtime.js     | 20 ++++++++++++++++---
 2 files changed, 22 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/nasty-pigs-lay.md

diff --git a/.changeset/nasty-pigs-lay.md b/.changeset/nasty-pigs-lay.md
new file mode 100644
index 0000000000..b7252b70f7
--- /dev/null
+++ b/.changeset/nasty-pigs-lay.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: when an unowned derived is tracked again, remove unowned flag
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 30f14b7356..65376ddf39 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -184,19 +184,29 @@ export function check_dirtiness(reaction) {
 			// If we are working with a disconnected or an unowned signal that is now connected (due to an active effect)
 			// then we need to re-connect the reaction to the dependency
 			if (is_disconnected || is_unowned_connected) {
+				var derived = /** @type {Derived} */ (reaction);
+
 				for (i = 0; i < length; i++) {
 					dependency = dependencies[i];
 
 					// We always re-add all reactions (even duplicates) if the derived was
 					// previously disconnected, however we don't if it was unowned as we
 					// de-duplicate dependencies in that case
-					if (is_disconnected || !dependency?.reactions?.includes(reaction)) {
-						(dependency.reactions ??= []).push(reaction);
+					if (is_disconnected || !dependency?.reactions?.includes(derived)) {
+						(dependency.reactions ??= []).push(derived);
 					}
 				}
 
 				if (is_disconnected) {
-					reaction.f ^= DISCONNECTED;
+					derived.f ^= DISCONNECTED;
+				}
+				var parent = derived.parent;
+
+				if (is_unowned_connected && parent !== null && (parent.f & UNOWNED) === 0) {
+					// If the derived is owned by another derived then mark it as owned agaub
+					// as the derived value might have been referenced in a different context
+					// and now has a reacive context managing it
+					derived.f ^= UNOWNED;
 				}
 			}
 
@@ -409,6 +419,10 @@ export function update_reaction(reaction) {
 		(flags & UNOWNED) !== 0 &&
 		(!is_flushing_effect || previous_reaction === null || previous_untracking);
 
+	if (skip_reaction) {
+		// debugger
+	}
+
 	derived_sources = null;
 	set_component_context(reaction.ctx);
 	untracking = false;