From a82515b11935216942a0d5edf9cc313f929f1305 Mon Sep 17 00:00:00 2001
From: Jane Kim <janecakemaster@gmail.com>
Date: Thu, 24 Sep 2026 21:21:03 -0700
Subject: [PATCH] Unlink a removed node from its parents when it was stale

---
 .changeset/remove-unlinks-stale-parents.md |  5 +++++
 packages/atom/src/internal/registry.ts     |  4 ----
 packages/atom/test/Atom.test.ts            | 16 ++++++++++++++++
 3 files changed, 21 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/remove-unlinks-stale-parents.md

diff --git a/.changeset/remove-unlinks-stale-parents.md b/.changeset/remove-unlinks-stale-parents.md
new file mode 100644
index 00000000..275d8482
--- /dev/null
+++ b/.changeset/remove-unlinks-stale-parents.md
@@ -0,0 +1,5 @@
+---
+"@effect-atom/atom": patch
+---
+
+Unlink a removed node from its parents when it was invalidated before removal, so the parents can be removed too.
diff --git a/packages/atom/src/internal/registry.ts b/packages/atom/src/internal/registry.ts
index fcc3ff07..4dc95b3a 100644
--- a/packages/atom/src/internal/registry.ts
+++ b/packages/atom/src/internal/registry.ts
@@ -441,10 +441,6 @@ class Node<A> {
     this.state = NodeState.removed
     this.listeners.clear()
 
-    if (this.lifetime === undefined) {
-      return
-    }
-
     this.disposeLifetime()
 
     if (this.previousParents === undefined) {
diff --git a/packages/atom/test/Atom.test.ts b/packages/atom/test/Atom.test.ts
index 1b48c949..d40389f2 100644
--- a/packages/atom/test/Atom.test.ts
+++ b/packages/atom/test/Atom.test.ts
@@ -335,6 +335,22 @@ describe("Atom", () => {
     unsubscribe()
   })
 
+  it("removes parents of a node that was invalidated before removal", async () => {
+    const parent = Atom.make(0)
+    const source = Atom.make(0)
+    const child = Atom.make((get) => get(parent) + get(source))
+    const registry = Registry.make()
+    const unmount = registry.mount(child)
+
+    unmount()
+    registry.set(source, 1)
+    await new Promise((resolve) => resolve(null))
+
+    const nodes = registry.getNodes()
+    assert.strictEqual(nodes.has(child), false)
+    assert.strictEqual(nodes.has(parent), false)
+  })
+
   it("refresh derived before mount resolves base effect", async () => {
     const baseAtom = Atom.make(
       Effect.succeed("value").pipe(Effect.delay(100))