node:net: finish an accepted socket whose native close leaves a write parked

src/js/node/net.ts

@@ -874,8 +874,10 @@ function SocketEmitEndNT(self, _err?) {
   }
   // A write that was waiting on the native drain can never complete once the
   // socket is gone - fail it so 'finish'/destroy are not stuck behind it.
+  // kclosed, not _err: a native close can carry no error. A half-open 'end'
+  // also lands here, and its write stays parked because it can still drain.
   const pendingWrite = self[kwriteCallback];
-  if (pendingWrite && (self.destroyed || _err)) {
+  if (pendingWrite && (self[kclosed] || self.destroyed)) {
     self[kwriteCallback] = null;
     pendingWrite(_err ?? $ERR_SOCKET_CLOSED());
   }

test/js/node/tls/node-tls-server.test.ts

@@ -2685,3 +2685,85 @@ describe("pauseOnConnect", () => {
     }
   });
 });
+
+it("an accepted socket emits 'close' when a write is the first to see the peer's reset", async () => {
+  // A send() that fails with the reset consumes the socket error, so the loop then sees a
+  // plain hangup and the native close carries no error. With the rest of the write still
+  // waiting for a drain, the socket emitted 'end' and nothing else: no write callback, no
+  // 'error', no 'close', and the server counted it forever.
+  //
+  // The server is a child process so that it can stop polling: it reports the accepted
+  // socket, then blocks on stdin until this process has reset the connection.
+  //
+  // A socket that never closes gives no event to wait for, so a second connection asks.
+  // Its handshake takes several turns of the server's loop, and the reset socket closes in
+  // the first of them or not at all. The server reports when the second connection arrives.
+  const serverScript = `
+    const tls = require("node:tls");
+    const fs = require("node:fs");
+    const events = [];
+    let accepted;
+    const server = tls.createServer(${JSON.stringify(COMMON_CERT)}, socket => {
+      if (accepted) {
+        server.getConnections((err, connections) => {
+          console.log(JSON.stringify({ events, connections }));
+          // Also the first socket, so that this process exits when it never closed.
+          accepted.destroy();
+          socket.destroy();
+          server.close();
+        });
+        return;
+      }
+      accepted = socket;
+      socket.on("error", () => events.push("error"));
+      socket.on("close", hadError => events.push("close:" + hadError));
+      socket.resume();
+      fs.writeSync(1, "accepted\\n");
+      fs.readSync(0, Buffer.alloc(1));
+      // More than the TLS layer takes once the wire rejects a record, so the rest is parked.
+      socket.write(Buffer.alloc(1 << 20));
+      fs.writeSync(1, "wrote\\n");
+    });
+    server.listen(0, "127.0.0.1", () => fs.writeSync(1, "port=" + server.address().port + "\\n"));
+  `;
+  await using proc = Bun.spawn({
+    cmd: [bunExe(), "-e", serverScript],
+    env: bunEnv,
+    stdin: "pipe",
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+  // Drain stderr while stdout is scanned, so a child that logs a lot cannot block on it.
+  const stderrText = proc.stderr.text();
+  let stdout = "";
+  let raw: net.Socket | undefined;
+  let probe: net.Socket | undefined;
+  let reset = false;
+  for await (const chunk of proc.stdout) {
+    stdout += Buffer.from(chunk).toString();
+    const port = /port=(\d+)/.exec(stdout);
+    if (port && !raw) {
+      raw = net.connect(Number(port[1]), "127.0.0.1");
+      raw.on("error", () => {});
+      connect({ socket: raw, rejectUnauthorized: false }).on("error", () => {});
+    }
+    if (raw && !reset && stdout.includes("accepted\n")) {
+      reset = true;
+      raw.resetAndDestroy();
+      proc.stdin.write("x");
+      proc.stdin.flush();
+    }
+    if (port && !probe && stdout.includes("wrote\n")) {
+      probe = connect({ port: Number(port[1]), host: "127.0.0.1", rejectUnauthorized: false });
+      probe.on("error", () => {});
+    }
+  }
+  const [stderr, exitCode] = await Promise.all([stderrText, proc.exited]);
+  probe?.destroy();
+  expect(stderr).toBe("");
+  const lines = stdout.trim().split("\n");
+  // The one connection left is the second one.
+  expect(JSON.parse(lines[lines.length - 1])).toEqual({ events: ["error", "close:true"], connections: 1 });
+  expect(proc.signalCode).toBeNull();
+  expect(exitCode).toBe(0);
+});