"net" and "Bun.connect" both seem to block aggressively, sequentially run and fail in uncatchable ways [TCP]

[ShanonJackson]

What version of Bun is running?

1.1.6

What platform is your computer?

Microsoft Windows NT 10.0.19045.0 x64

What steps can reproduce the bug?

(async () => {
	const sockets = new Array(100).fill({ ip: "10.10.10.10", port: 6881 }).map(async ({ ip, port }) => {
		return await Bun.connect({
			hostname: ip,
			port: port,
			socket: {
				data(socket, data) {
					console.log("data");
				},
				open(socket) {
					console.log("open");
				},
				close(socket) {
					// console.log("SOCKET CLOSED");
				},
				drain(socket) {
					// console.log("SOCKET DRAIN");
				},
				error(socket, error) {
					console.log("PEER TCP ERROR: ", { error });
					socket.end();
				},
				connectError(socket, error) {
					console.log("CONNECT ERROR", { error });
					socket.end();
				},
				end(socket) {
					console.log("END");
					socket.end();
				},
				handshake(socket) {
					// console.log("HANDSHAKE");
					// Bitfield message indicating that we have no pieces
					// const bitfieldMessage = Buffer.alloc(5);
					// bitfieldMessage.writeUInt32BE(1, 0); // Length prefix
					// bitfieldMessage.writeUInt8(5, 4); // Message ID for bitfield
					// socket.write(bitfieldMessage);
				},
				timeout(socket) {
					socket.end();
				},
			},
		}).catch((e) => {
			console.log({ e });
			return null;
		});
	});
	await Promise.all(sockets);
	console.log("finished");
})();

What is the expected behavior?

1: Near identical code using "net" fails in same ways (so not exclusive to Bun TCP)
2: Running near identical code with NODE runtime using node:net succeeds (so NodeJS handles this fine)
3: Code runs incredibly slowly when real ip / ports are used 300 sockets may take 1hr to all timeout (in node this is several seconds)
4: ECONNREFUSED crashing the program seems impossible to catch either with try/catch or .catch

What do you see instead?

• [On WSL] - the program just hangs.
• [On Windows] - Crashes in uncatchable way when invalid ip/port is used. (ECONNREFUSED)
• [On All OS ] - Seems to resolve sequentially timing out slowly when 100's of sockets are created to valid ip/ports

Additional information

Use case for us:

• We help run and maintain the nodes on the bittorrent network we need to be able to connect to many peers over TCP to exchange information.
• In Node we can create 100's of sockets to many peers and close them once we have the information we need, in Bun it looks like a single socket works but many sockets seems to not work.

[nektro]

does this work better with the following change? having await in the .map feels at odds with later calling Promise.all which would then await in parallel for you.

-return await Bun.connect
+return Bun.connect

[ShanonJackson]

@nektro

Sorry that's just an artifact of pasting some code around to get a smaller example.

No this doesn't help, as mentioned in post title this also breaks in same way using net.createConnection which is NodeJS's TCP API supported in Bun. 1 Connection is fine, many connections stalls the program or fails. Removing await here does nothing. net.createConnection doesn't even have a Promise based API. Program runs fine using Node (and swapping Bun related API's for their NodeJS counterpart).

This is preventing us from finishing our Bun migration.

[ShanonJackson]

https://bun.sh/blog/bun-v1.1.10#fixed-regression-in-v1-1-9-with-hanging-bun-install-on-windows

This issue is now fixed. Still have many more so will log new issues.

Thanks.