http: do not emit socket errors after complete response

Signed-off-by: Archkon <180910180+Archkon@users.noreply.github.com>

Author: Archkon

lib/_http_client.js

@@ -744,7 +744,12 @@ function socketErrorListener(err) {
     // For Safety. Some additional errors might fire later on
     // and we need to make sure we don't double-fire the error event.
     socket._hadError = true;
-    emitErrorEvent(req, err);
+    // If a complete response has already been received, the request
+    // succeeded at the HTTP layer. Treat later socket errors as connection
+    // teardown, not as errors for this ClientRequest.
+    if (!req.res?.complete) {
+      emitErrorEvent(req, err);
+    }
   }
 
   const parser = socket.parser;

test/parallel/test-http-client-complete-response-reset.js

@@ -0,0 +1,61 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+const MAX_BODY_LENGTH = 1024 * 1024;
+
+const server = http.createServer(common.mustCall((request, response) => {
+  let body = '';
+
+  request.setEncoding('utf8');
+  request.on('data', function onData(chunk) {
+    body += chunk;
+    if (body.length > MAX_BODY_LENGTH) {
+      response.writeHead(413);
+      response.end();
+      request.off('data', onData);
+      request.destroy();
+    }
+  });
+
+  request.on('end', common.mustNotCall());
+  request.on('close', common.mustCall(() => {
+    assert.strictEqual(request.complete, false);
+    assert.ok(body.length > MAX_BODY_LENGTH);
+  }));
+}));
+
+server.listen(0, common.mustCall(() => {
+  const body = JSON.stringify({
+    a: 'x'.repeat(512 * 1024),
+    b: 'x'.repeat(512 * 1024),
+    c: 'x'.repeat(512 * 1024),
+    d: 'x'.repeat(512 * 1024),
+  }, null, '\t');
+
+  let response;
+  const req = http.request({
+    method: 'POST',
+    port: server.address().port,
+    headers: {
+      'content-type': 'application/json',
+    },
+  }, common.mustCall((res) => {
+    response = res;
+    assert.strictEqual(res.statusCode, 413);
+    // Deliberately do not consume the response body. A complete HTTP response
+    // should not be followed by a late ClientRequest ECONNRESET.
+  }));
+
+  req.on('error', common.mustNotCall());
+  req.on('close', common.mustCall(() => {
+    assert(response);
+    assert.strictEqual(response.complete, true);
+    server.close();
+  }));
+
+  req.write(body);
+  req.end();
+}));