--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-poll-multiple-handles.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,104 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <errno.h>
+
+#ifndef _WIN32
+# include <fcntl.h>
+# include <sys/socket.h>
+# include <unistd.h>
+#endif
+
+#include "uv.h"
+#include "task.h"
+
+
+static int close_cb_called = 0;
+
+
+static void close_cb(uv_handle_t* handle) {
+  close_cb_called++;
+}
+
+static void poll_cb(uv_poll_t* handle, int status, int events) {
+  /* Not a bound socket, linux immediately reports UV_READABLE, other OS do not */
+  ASSERT_EQ(events, UV_READABLE);
+}
+
+TEST_IMPL(poll_multiple_handles) {
+  uv_os_sock_t sock;
+  uv_poll_t first_poll_handle, second_poll_handle;
+
+#ifdef _WIN32
+  {
+    struct WSAData wsa_data;
+    int r = WSAStartup(MAKEWORD(2, 2), &wsa_data);
+    ASSERT_OK(r);
+  }
+#endif
+
+  sock = socket(AF_INET, SOCK_STREAM, 0);
+#ifdef _WIN32
+  ASSERT_NE(sock, INVALID_SOCKET);
+#else
+  ASSERT_NE(sock, -1);
+#endif
+  ASSERT_OK(uv_poll_init_socket(uv_default_loop(),
+                                &first_poll_handle,
+                                sock));
+  ASSERT_OK(uv_poll_init_socket(uv_default_loop(),
+                                &second_poll_handle,
+                                sock));
+
+  ASSERT_OK(uv_poll_start(&first_poll_handle, UV_READABLE, poll_cb));
+
+  /* We may not start polling while another polling handle is active
+   * on that fd.
+   */
+#ifndef _WIN32
+  /* We do not track handles in an O(1) lookupable way on Windows,
+   * so not checking that here.
+   */
+  ASSERT_EQ(uv_poll_start(&second_poll_handle, UV_READABLE, poll_cb),
+            UV_EEXIST);
+#endif
+
+  /* After stopping the other polling handle, we now should be able to poll */
+  ASSERT_OK(uv_poll_stop(&first_poll_handle));
+  ASSERT_OK(uv_poll_start(&second_poll_handle, UV_READABLE, poll_cb));
+
+  /* Closing an already stopped polling handle is safe in any case */
+  uv_close((uv_handle_t*) &first_poll_handle, close_cb);
+
+  uv_unref((uv_handle_t*) &second_poll_handle);
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+  ASSERT_EQ(1, close_cb_called);
+  uv_ref((uv_handle_t*) &second_poll_handle);
+
+  ASSERT(uv_is_active((uv_handle_t*) &second_poll_handle));
+  uv_close((uv_handle_t*) &second_poll_handle, close_cb);
+
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+  ASSERT_EQ(2, close_cb_called);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}