minimal fix

Author: cirospaciari

packages/bun-usockets/src/eventing/epoll_kqueue.c

@@ -360,11 +360,11 @@ int kqueue_change(int kqfd, int fd, int old_events, int new_events, void *user_d
     if(!is_readable && !is_writable) {
         if(!(old_events & LIBUS_SOCKET_WRITABLE)) {
             // if we are not reading or writing, we need to add writable to receive FIN
-            EV_SET64(&change_list[change_length++], fd, EVFILT_WRITE, EV_ADD, 0, 0, (uint64_t)(void*)user_data, 0, 0);
+            EV_SET64(&change_list[change_length++], fd, EVFILT_WRITE, EV_ADD | EV_ONESHOT, 0, 0, (uint64_t)(void*)user_data, 0, 0);
         }
     } else if ((new_events & LIBUS_SOCKET_WRITABLE) != (old_events & LIBUS_SOCKET_WRITABLE)) {
         /* Do they differ in writable? */
-        EV_SET64(&change_list[change_length++], fd, EVFILT_WRITE, (new_events & LIBUS_SOCKET_WRITABLE) ? EV_ADD : EV_DELETE, 0, 0, (uint64_t)(void*)user_data, 0, 0);
+        EV_SET64(&change_list[change_length++], fd, EVFILT_WRITE, (new_events & LIBUS_SOCKET_WRITABLE) ? EV_ADD | EV_ONESHOT : EV_DELETE, 0, 0, (uint64_t)(void*)user_data, 0, 0);
     }
     int ret;
     do {

test/js/bun/http/bun-server.test.ts

@@ -1,9 +1,13 @@
 import type { Server, ServerWebSocket, Socket } from "bun";
 import { describe, expect, test } from "bun:test";
-import { bunEnv, bunExe, rejectUnauthorizedScope, tempDirWithFiles, tls } from "harness";
+import { bunEnv, bunExe, bunRun, rejectUnauthorizedScope, tempDirWithFiles, tls } from "harness";
 import path from "path";
 
 describe.concurrent("Server", () => {
+  test("should not use 100% CPU when websocket is idle", async () => {
+    const { stderr } = bunRun(path.join(import.meta.dir, "bun-websocket-cpu-fixture.js"));
+    expect(stderr).toBe("");
+  });
   test("normlizes incoming request URLs", async () => {
     using server = Bun.serve({
       fetch(request) {