http: prevent aborted event when request is complete

When socket is closed on a response for a request that is being piped to a stream
there is a condition where aborted event will be fired to http client when socket is
closing and the incomingMessage stream is still set to readable.

Fixes: nodejs#18756

lib/_http_client.js

@@ -321,7 +321,7 @@ function socketCloseListener() {
   var parser = socket.parser;
   if (req.res && req.res.readable) {
     // Socket closed before we emitted 'end' below.
-    req.res.emit('aborted');
+    if (!req.res.complete) req.res.emit('aborted');
     var res = req.res;
     res.on('end', function() {
       res.emit('close');

test/parallel/test-http-client-spurious-aborted.js

@@ -0,0 +1,83 @@
+'use strict';
+
+const common = require('../common');
+const http = require('http');
+const assert = require('assert');
+const fs = require('fs');
+const Countdown = require('../common/countdown');
+
+function cleanup(fname) {
+  try {
+    if (fs.statSync(fname)) fs.unlinkSync(fname);
+  } catch (err) {}
+}
+
+const N = 2;
+const fname = '/dev/null';
+let abortRequest = true;
+
+const server = http.Server(common.mustCall((req, res) => {
+  const headers = { 'Content-Type': 'text/plain' };
+  headers['Content-Length'] = 50;
+  const socket = res.socket;
+  res.writeHead(200, headers);
+  setTimeout(() => res.write('aaaaaaaaaa'), 100);
+  setTimeout(() => res.write('bbbbbbbbbb'), 200);
+  setTimeout(() => res.write('cccccccccc'), 300);
+  setTimeout(() => res.write('dddddddddd'), 400);
+  if (abortRequest) {
+    setTimeout(() => socket.destroy(), 600);
+  } else {
+    setTimeout(() => res.end('eeeeeeeeee'), 1000);
+  }
+}, N));
+
+server.listen(0, common.mustCall(() => {
+  cleanup(fname);
+  download();
+}));
+
+const finishCountdown = new Countdown(N, common.mustCall(() => {
+  server.close();
+}));
+const reqCountdown = new Countdown(N, common.mustCall());
+
+function download() {
+  const opts = {
+    port: server.address().port,
+    path: '/',
+  };
+  const req = http.get(opts);
+  req.on('error', common.mustNotCall());
+  req.on('response', (res) => {
+    assert.strictEqual(res.statusCode, 200);
+    assert.strictEqual(res.headers.connection, 'close');
+    let aborted = false;
+    const fstream = fs.createWriteStream(fname);
+    res.pipe(fstream);
+    const _handle = res.socket._handle;
+    _handle._close = res.socket._handle.close;
+    _handle.close = function(callback) {
+      _handle._close();
+      // set readable to true event though request is complete
+      if (res.complete) res.readable = true;
+      callback();
+    };
+    res.on('end', common.mustCall(() => {
+      reqCountdown.dec();
+    }));
+    res.on('aborted', () => {
+      aborted = true;
+    });
+    res.on('error', common.mustNotCall());
+    fstream.on('finish', () => {
+      assert.strictEqual(aborted, abortRequest);
+      cleanup(fname);
+      finishCountdown.dec();
+      if (finishCountdown.remaining === 0) return;
+      abortRequest = false; // next one should be a good response
+      download();
+    });
+  });
+  req.end();
+}