node:net: fix handle leak (#22913)

scripts/runner.node.mjs

@@ -80,7 +80,7 @@ function getNodeParallelTestTimeout(testPath) {
   if (testPath.includes("test-dns")) {
     return 90_000;
   }
-  return 10_000;
+  return 20_000;
 }
 
 process.on("SIGTRAP", () => {

src/bun.js/api/bun/socket.zig

@@ -111,7 +111,7 @@ pub fn NewSocket(comptime ssl: bool) type {
         pub fn doConnect(this: *This, connection: Listener.UnixOrHost) !void {
             bun.assert(this.socket_context != null);
             this.ref();
-            errdefer this.deref();
+            defer this.deref();
 
             switch (connection) {
                 .host => |c| {

test/js/node/net/handle-leak.test.ts

@@ -0,0 +1,77 @@
+import { expect } from "bun:test";
+import { isASAN, isWindows } from "harness";
+import * as net from "node:net";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { setTimeout } from "node:timers/promises";
+
+const listen_path = join(tmpdir(), "test-net-successful-connection-handle-leak.sock");
+
+const { promise, resolve } = Promise.withResolvers();
+const server = net
+  .createServer()
+  .listen(listen_path)
+  .on("listening", () => resolve());
+await promise;
+const address = server.address();
+console.log("server address", address);
+
+let started;
+
+started = 0;
+while (started < 50_000) {
+  const promises: Promise<void>[] = [];
+  for (let i = 0; i < 100; i++) {
+    const { promise, resolve, reject } = Promise.withResolvers<void>();
+    const socket = net
+      .connect({ path: listen_path })
+      .on("connect", () => {
+        socket.on("close", () => resolve());
+        socket.end();
+      })
+      .on("error", e => {
+        reject(e);
+      });
+
+    promises.push(promise);
+    started++;
+  }
+  await Promise.all(promises);
+  await setTimeout(1);
+  console.log(`Completed ${started} connections. RSS: ${(process.memoryUsage.rss() / 1024 / 1024) | 0} MB`);
+}
+
+Bun.gc(true);
+const warmup_rss = process.memoryUsage.rss();
+
+started = 0;
+while (started < 100_000) {
+  const promises: Promise<void>[] = [];
+  for (let i = 0; i < 100; i++) {
+    const { promise, resolve, reject } = Promise.withResolvers<void>();
+    const socket = net
+      .connect({ path: listen_path })
+      .on("connect", () => {
+        socket.on("close", () => resolve());
+        socket.end();
+      })
+      .on("error", e => {
+        reject(e);
+      });
+
+    promises.push(promise);
+    started++;
+  }
+  await Promise.all(promises);
+  await setTimeout(1);
+  console.log(`Completed ${started} connections. RSS: ${(process.memoryUsage.rss() / 1024 / 1024) | 0} MB`);
+}
+
+const post_rss = process.memoryUsage.rss();
+
+server.close();
+
+let margin = 1024 * 1024 * 15;
+if (isWindows) margin = 1024 * 1024 * 20;
+if (isASAN) margin = 1024 * 1024 * 60;
+expect(post_rss - warmup_rss).toBeLessThan(margin);