Fix bug with // @bun annotation in main thread (#3855)

* Uncomment test

* Fix bug with // @bun + async transpiler

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

3 files changed, 37 insertions, 0 deletions

diff --git a/test/transpiler/async-transpiler-entry.js b/test/transpiler/async-transpiler-entry.js
new file mode 100644
index 000000000..179a4e6a8
--- /dev/null
+++ b/test/transpiler/async-transpiler-entry.js
@@ -0,0 +1 @@
+export { default } from "./async-transpiler-imported.js";
diff --git a/test/transpiler/async-transpiler-imported.js b/test/transpiler/async-transpiler-imported.js
new file mode 100644
index 000000000..ed2f22490
--- /dev/null
+++ b/test/transpiler/async-transpiler-imported.js
@@ -0,0 +1,6 @@
+// @bun
+export default 42;
+
+if (import.meta.main) {
+  console.log("Hello world!");
+}
diff --git a/test/transpiler/runtime-transpiler.test.ts b/test/transpiler/runtime-transpiler.test.ts
new file mode 100644
index 000000000..b3f545719
--- /dev/null
+++ b/test/transpiler/runtime-transpiler.test.ts
@@ -0,0 +1,30 @@
+import { beforeEach, describe, expect, test } from "bun:test";
+import { bunEnv, bunExe } from "harness";
+
+describe("// @bun", () => {
+  beforeEach(() => {
+    delete require.cache[require.resolve("./async-transpiler-entry")];
+    delete require.cache[require.resolve("./async-transpiler-imported")];
+  });
+
+  test("async transpiler", async () => {
+    const { default: value } = await import("./async-transpiler-entry");
+    expect(value).toBe(42);
+  });
+
+  test("require()", async () => {
+    const { default: value } = require("./async-transpiler-entry");
+    expect(value).toBe(42);
+  });
+
+  test("synchronous", async () => {
+    const { stdout, exitCode } = Bun.spawnSync({
+      cmd: [bunExe(), require.resolve("./async-transpiler-imported")],
+      cwd: import.meta.dir,
+      env: bunEnv,
+      stderr: "inherit",
+    });
+    expect(stdout.toString()).toBe("Hello world!\n");
+    expect(exitCode).toBe(0);
+  });
+});