Merge pull request #6274 from cloudflare/jasnell/als-gc

Author: jasnell

src/workerd/api/node/tests/BUILD.bazel

@@ -722,3 +722,9 @@ wd_test(
     args = ["--experimental"],
     data = ["buffer-effective-size-concat-test.js"],
 )
+
+wd_test(
+    src = "als-gc-test.wd-test",
+    args = ["--experimental"],
+    data = ["als-gc-test.js"],
+)

src/workerd/api/node/tests/als-gc-test.js

@@ -0,0 +1,21 @@
+import { AsyncLocalStorage } from 'node:async_hooks';
+
+const store = new AsyncLocalStorage();
+
+export const test = {
+  test() {
+    const outerValue = crypto.randomUUID();
+    ({ [outerValue]: `value doesn't matter here` });
+    store.run(outerValue, () => {
+      for (let i = 0; i < 1_000; i++) {
+        const storeValue = store.getStore();
+        if (!storeValue) {
+          throw new Error(`Failed on attempt ${i}.`);
+        }
+        for (let j = 0; j < 1_000; j++) {
+          (() => Math.random())();
+        }
+      }
+    });
+  },
+};

src/workerd/api/node/tests/als-gc-test.wd-test

@@ -0,0 +1,14 @@
+using Workerd = import "/workerd/workerd.capnp";
+
+const unitTests :Workerd.Config = (
+  services = [
+    ( name = "als-gc-test",
+      worker = (
+        modules = [
+          (name = "worker", esModule = embed "als-gc-test.js")
+        ],
+        compatibilityFlags = ["nodejs_compat", "nodejs_compat_v2"]
+      )
+    ),
+  ],
+);

src/workerd/jsg/async-context.c++

@@ -187,8 +187,7 @@ v8::Local<v8::Object> AsyncContextFrame::getJSWrapper(Lock& js) {
 }
 
 void AsyncContextFrame::jsgVisitForGc(GcVisitor& visitor) {
-  for (auto& entry: storage) {
-    visitor.visit(entry.value);
-  }
+  // tracing will make the members weak and will allow
+  // them to be gc'd, which is not what we want.
 }
 }  // namespace workerd::jsg