node:http: set req.complete when the body of a destroyed request ends - #44309

Repro. The listener breaks out of a for await loop over the request after the first chunk and answers. The client then sends the rest of the body and one more request.

import http from "node:http";
import net from "node:net";
import { once } from "node:events";
let first;
const server = http.createServer(async (req, res) => {
  if (req.url === "/second") return res.end(String(first.complete));
  first = req;
  for await (const chunk of req) break;
  res.end("first");
});
server.listen(0, "127.0.0.1");
await once(server, "listening");
const socket = net.connect(server.address().port, "127.0.0.1");
let received = "";
socket.on("data", chunk => (received += chunk));
socket.write("POST /first HTTP/1.1\r\nHost: x\r\nContent-Length: 10\r\n\r\nhello");
while (!received.endsWith("first")) await once(socket, "data");
socket.write("worldGET /second HTTP/1.1\r\nHost: x\r\nConnection: close\r\n\r\n");
await once(socket, "close");
console.log(received.slice(received.lastIndexOf("\r\n\r\n") + 4));
server.close();

Node v26.3.0 prints true. main bf42a52 prints false. This branch prints true.

Rows. 2 ways to destroy the request (for await break, failed pipeline()) by 2 framings (Content-Length, chunked): req.complete after the body ended is true in Node and on this branch for all 4, and false on main for all 4. While the body still arrives, and when the client closes the connection before the body ends, it is false everywhere.

What Node does. parserOnMessageComplete (_http_common.js) sets stream.complete = true and pushes the end of the stream. It does not look at destroyed. parserOnBody drops the chunks of a destroyed stream.

Why the callback tests the event. The native server also calls ondata with the last-chunk flag when the connection closes (abort event). That call must not set complete. The two stays false tests cover it.

A body larger than the stream buffer. Node stops reading such a connection when the request is destroyed and never answers a later request on it (a 4 MiB body, then a second request: Node gets no response in 8 s). Bun keeps reading, as before this change, and answers. req.complete of the destroyed request is then true.

Measurements. Release builds, Linux x64. perf and valgrind are not installed on the machine, so the instruction count for each request is missing.

Suites. Debug build: node-http-req-complete.test.ts (33 pass). Release builds of main and of #44310, which holds this change, one after the other: see the Notes of #44310.

Observed on Linux x64 only.