Fork the current scope in withIsolationScope and withSetIsolationScope

The strategy was derived from the deno/cloudflare one, which passes the current
scope by reference. Both the OpenTelemetry strategy and v10's node-core light
strategy clone it, so without this, current-scope mutations leak out of an
isolation fork.

Author: andreiborza

packages/server-utils/src/async-context.ts

@@ -54,8 +54,11 @@ export function setAsyncLocalStorageAsyncContextStrategy(): void {
     });
   }
 
+  // The current scope is forked alongside the isolation scope, matching the OpenTelemetry strategy
+  // (`buildContextWithSentryScopes` clones it on every fork). Sharing it by reference would let
+  // current-scope mutations inside the callback leak back out to the caller.
   function withIsolationScope<T>(callback: (isolationScope: Scope) => T): T {
-    const scope = getScopes().scope;
+    const scope = getScopes().scope.clone();
     const isolationScope = getScopes().isolationScope.clone();
 
     return asyncStorage.run({ scope, isolationScope }, () => {
@@ -64,7 +67,7 @@ export function setAsyncLocalStorageAsyncContextStrategy(): void {
   }
 
   function withSetIsolationScope<T>(isolationScope: Scope, callback: (isolationScope: Scope) => T): T {
-    const scope = getScopes().scope;
+    const scope = getScopes().scope.clone();
     return asyncStorage.run({ scope, isolationScope }, () => {
       return callback(isolationScope);
     });

packages/server-utils/test/async-context.test.ts

@@ -166,6 +166,40 @@ describe('withIsolationScope()', () => {
         done();
       });
     }));
+
+  it('forks the current scope as well, so mutations do not leak out', () =>
+    new Promise<void>(done => {
+      const initialScope = getCurrentScope();
+      initialScope.setTag('aa', 'aa');
+
+      withIsolationScope(() => {
+        const scope = getCurrentScope();
+        expect(scope).not.toBe(initialScope);
+        expect(scope.getScopeData().tags).toEqual({ aa: 'aa' });
+
+        scope.setTag('bb', 'bb');
+        done();
+      });
+
+      expect(initialScope.getScopeData().tags).toEqual({ aa: 'aa' });
+    }));
+
+  it('forks the current scope as well when passing an isolation scope', () =>
+    new Promise<void>(done => {
+      const initialScope = getCurrentScope();
+      initialScope.setTag('aa', 'aa');
+
+      withIsolationScope(new Scope(), () => {
+        const scope = getCurrentScope();
+        expect(scope).not.toBe(initialScope);
+        expect(scope.getScopeData().tags).toEqual({ aa: 'aa' });
+
+        scope.setTag('bb', 'bb');
+        done();
+      });
+
+      expect(initialScope.getScopeData().tags).toEqual({ aa: 'aa' });
+    }));
 });
 
 describe('AsyncLocalStorage re-use', () => {