From cb39509bf7146aa70c472412d8007d2ac43febb0 Mon Sep 17 00:00:00 2001
From: Yoshiya Hinosawa <stibium121@gmail.com>
Date: Fri, 6 Sep 2024 16:16:33 +0900
Subject: [PATCH 1/2] fix(ext/node): delay accept() call 2 ticks in
 net.Server#listen

---
 .../polyfills/internal_binding/tcp_wrap.ts     | 10 +++++++++-
 tests/unit_node/net_test.ts                    | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/ext/node/polyfills/internal_binding/tcp_wrap.ts b/ext/node/polyfills/internal_binding/tcp_wrap.ts
index 9897bccd06d3da..4b57a7e1ecdf24 100644
--- a/ext/node/polyfills/internal_binding/tcp_wrap.ts
+++ b/ext/node/polyfills/internal_binding/tcp_wrap.ts
@@ -45,6 +45,7 @@ import {
   INITIAL_ACCEPT_BACKOFF_DELAY,
   MAX_ACCEPT_BACKOFF_DELAY,
 } from "ext:deno_node/internal_binding/_listen.ts";
+import { nextTick } from "ext:deno_node/_next_tick.ts";
 
 /** The type of TCP socket. */
 enum socketType {
@@ -228,7 +229,14 @@ export class TCP extends ConnectionWrap {
     this.#port = address.port;
 
     this.#listener = listener;
-    this.#accept();
+
+    // TODO(kt3k): Delays the accept() call 2 ticks. Deno.Listener can't be closed
+    // synchronously when accept() is called. By delaying the accept() call,
+    // the user can close the server synchronously in the callback of listen().
+    // This workaround enables `npm:detect-port` to work correctly.
+    // Remove these nextTick calls when the below issue resolved:
+    // https://github.com/denoland/deno/issues/25480
+    nextTick(nextTick, () => this.#accept());
 
     return 0;
   }
diff --git a/tests/unit_node/net_test.ts b/tests/unit_node/net_test.ts
index 708d06386caf38..5cf9bd124f9338 100644
--- a/tests/unit_node/net_test.ts
+++ b/tests/unit_node/net_test.ts
@@ -228,3 +228,21 @@ Deno.test("[node/net] BlockList doesn't leak resources", () => {
   blockList.addAddress("1.1.1.1");
   assert(blockList.check("1.1.1.1"));
 });
+
+Deno.test("[node/net] net.Server can listen on the same port immediately after it's closed", async () => {
+  const serverClosed = Promise.withResolvers<void>();
+  const server = net.createServer();
+  server.on("error", (e) => {
+    console.error(e);
+  });
+  server.listen(0, () => {
+    const port = (server.address() as any).port;
+    server.close();
+    server.listen(port, () => {
+      server.close(() => {
+        serverClosed.resolve();
+      });
+    });
+  })
+  await serverClosed.promise;
+});

From 6af4a4795fd67c461a9824ed142d76e922a62dce Mon Sep 17 00:00:00 2001
From: Yoshiya Hinosawa <stibium121@gmail.com>
Date: Fri, 6 Sep 2024 16:43:04 +0900
Subject: [PATCH 2/2] fmt, fix lint

---
 tests/unit_node/net_test.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tests/unit_node/net_test.ts b/tests/unit_node/net_test.ts
index 5cf9bd124f9338..8196874f301111 100644
--- a/tests/unit_node/net_test.ts
+++ b/tests/unit_node/net_test.ts
@@ -236,13 +236,14 @@ Deno.test("[node/net] net.Server can listen on the same port immediately after i
     console.error(e);
   });
   server.listen(0, () => {
-    const port = (server.address() as any).port;
+    // deno-lint-ignore no-explicit-any
+    const { port } = server.address() as any;
     server.close();
     server.listen(port, () => {
       server.close(() => {
         serverClosed.resolve();
       });
     });
-  })
+  });
   await serverClosed.promise;
 });