From 4f6b927c5e80d1c322aa27620087f0bdf86ea782 Mon Sep 17 00:00:00 2001
From: robobun <117481402+robobun@users.noreply.github.com>
Date: Sun, 16 Aug 2026 11:19:22 +0000
Subject: [PATCH] test(worker_threads): stress terminate() during preload
 module resolution

Covers oven-sh/WebKit#391 (JSModuleLoader::hostLoadImportedModule
propagating a TerminationException from resolve() instead of caching it
as a resolution failure), which is already in the WebKit pin on main.
The child calibrates a warm worker's time-to-online and sweeps
terminate() through the tail of startup against workers with explicit
node: preloads; on the unfixed engine it aborts on
ExceptionScope::assertNoException in continueDynamicImport.
---
 .../worker-terminate-during-preload.test.ts   | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 test/js/node/worker_threads/worker-terminate-during-preload.test.ts

diff --git a/test/js/node/worker_threads/worker-terminate-during-preload.test.ts b/test/js/node/worker_threads/worker-terminate-during-preload.test.ts
new file mode 100644
index 000000000000..a2872ec0d142
--- /dev/null
+++ b/test/js/node/worker_threads/worker-terminate-during-preload.test.ts
@@ -0,0 +1,71 @@
+import { expect, test } from "bun:test";
+import { bunEnv, bunExe, isDebug } from "harness";
+
+// Terminating a node:worker_threads Worker while its startup preloads are
+// running can land the NeedTermination trap inside
+// JSModuleLoader::hostLoadImportedModule's resolve() call. JSC used to treat
+// the resulting TerminationException like an ordinary resolution error: it
+// cached it in m_resolutionFailures, returned early from
+// rejectWithCaughtException (TRY_CLEAR_EXCEPTION won't clear a termination),
+// and entered continueDynamicImport with the termination still pending on the
+// VM, where scope.assertNoException() aborts under
+// ENABLE(EXCEPTION_SCOPE_VERIFICATION) (debug/ASAN builds).
+//
+// The window is the tail end of worker startup, so the child calibrates on a
+// warm worker's time-to-'online' and sweeps terminate() through a band just
+// below it. Explicit builtin preloads widen the cumulative resolve() window so
+// the sweep lands in it regardless of host speed.
+test(
+  "terminate() during worker preload does not abort in the module loader",
+  async () => {
+    const script = /* js */ `
+      const { Worker } = require("node:worker_threads");
+      const preload = [
+        "node:events", "node:path", "node:util", "node:url", "node:buffer",
+        "node:stream", "node:os", "node:fs", "node:crypto", "node:assert",
+        "node:querystring", "node:string_decoder", "node:timers", "node:zlib",
+      ];
+      async function timeToOnline() {
+        const t0 = Bun.nanoseconds();
+        const w = new Worker("", { eval: true, preload });
+        await new Promise((res, rej) => {
+          w.once("online", res);
+          w.once("error", rej);
+          w.once("exit", code => rej(new Error("worker exited before 'online' with code " + code)));
+        });
+        const dt = Bun.nanoseconds() - t0;
+        await w.terminate();
+        return dt;
+      }
+      (async () => {
+        await timeToOnline(); // cold; discard
+        const T = Math.min(await timeToOnline(), await timeToOnline());
+        for (let f = 0.55; f <= 1.05; f += 0.02) {
+          const w = new Worker("", { eval: true, preload });
+          const spinUntil = Bun.nanoseconds() + T * f;
+          while (Bun.nanoseconds() < spinUntil) {}
+          await w.terminate();
+        }
+        console.log("ok");
+      })().catch(e => { console.error(e); process.exit(1); });
+    `;
+
+    await using proc = Bun.spawn({
+      cmd: [bunExe(), "-e", script],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+
+    // stderr is kept in the assertion object so an abort's output appears in
+    // the failure diff, but not matched exactly (debug/ASAN builds may emit
+    // benign warnings on this lane).
+    expect({ stdout: stdout.trim(), exitCode, stderr }).toEqual({
+      stdout: "ok",
+      exitCode: 0,
+      stderr: expect.any(String),
+    });
+  },
+  isDebug ? 240_000 : 30_000,
+);