From 39db211414e90c8db8fdad7dc8ce5b4661bcfaef Mon Sep 17 00:00:00 2001
From: Michael Arnaldi <michael.arnaldi@effectful.co>
Date: Fri, 27 Dec 2024 14:00:14 +0100
Subject: [PATCH] Avoid putting symbols in global to fix incompatibility with
 Temporal Sandbox. (#4196)

---
 .changeset/sweet-bears-help.md     |  7 +++++++
 packages/effect/src/GlobalValue.ts | 14 ++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/sweet-bears-help.md

diff --git a/.changeset/sweet-bears-help.md b/.changeset/sweet-bears-help.md
new file mode 100644
index 00000000000..2c6039a95be
--- /dev/null
+++ b/.changeset/sweet-bears-help.md
@@ -0,0 +1,7 @@
+---
+"effect": patch
+---
+
+Avoid putting symbols in global to fix incompatibility with Temporal Sandbox.
+
+After speaking with James Watkins-Harvey we realized current Effect escapes the Temporal Worker sandbox that doesn't look for symbols when restoring global context in the isolate they create leading to memory leaks.
diff --git a/packages/effect/src/GlobalValue.ts b/packages/effect/src/GlobalValue.ts
index 7308a15584f..5987615fa0c 100644
--- a/packages/effect/src/GlobalValue.ts
+++ b/packages/effect/src/GlobalValue.ts
@@ -14,13 +14,9 @@
  */
 import * as version from "./internal/version.js"
 
-const globalStoreId = Symbol.for(`effect/GlobalValue/globalStoreId/${version.getCurrentVersion()}`)
+const globalStoreId = `effect/GlobalValue/globalStoreId/${version.getCurrentVersion()}`
 
-if (!(globalStoreId in globalThis)) {
-  ;(globalThis as any)[globalStoreId] = new Map()
-}
-
-const globalStore = (globalThis as any)[globalStoreId] as Map<unknown, any>
+let globalStore: Map<unknown, any>
 
 /**
  * Retrieves or computes a global value associated with the given `id`. If the value for this `id`
@@ -46,6 +42,12 @@ const globalStore = (globalThis as any)[globalStoreId] as Map<unknown, any>
  * @since 2.0.0
  */
 export const globalValue = <A>(id: unknown, compute: () => A): A => {
+  if (!globalStore) {
+    // @ts-expect-error
+    globalThis[globalStoreId] ??= new Map()
+    // @ts-expect-error
+    globalStore = globalThis[globalStoreId] as Map<unknown, any>
+  }
   if (!globalStore.has(id)) {
     globalStore.set(id, compute())
   }