http: resume kept-alive when no body allowed

In accordance with https://www.rfc-editor.org/rfc/rfc9112#name-message-body-length: HEAD, 1xx, 204, and 304 responses cannot contain a message body.

If a socket will be kept-alive, resume the socket during parsing so that it may be returned to the free pool.

Fixes #47228

Author: mweberxyz

lib/_http_client.js

@@ -607,6 +607,14 @@ function statusIsInformational(status) {
   return (status < 200 && status >= 100 && status !== 101);
 }
 
+function responseCannotContainMessageBody(status, method) {
+  // RFC9112 Section 6.1.1
+  return method === 'HEAD'
+    || status === 204
+    || status === 304
+    || statusIsInformational(status)
+}
+
 // client
 function parserOnIncomingClient(res, shouldKeepAlive) {
   const socket = this.socket;
@@ -654,11 +662,19 @@ function parserOnIncomingClient(res, shouldKeepAlive) {
     return 1;  // Skip body but don't treat as Upgrade.
   }
 
-  if (req.shouldKeepAlive && !shouldKeepAlive && !req.upgradeOrConnect) {
+  if (req.shouldKeepAlive && !req.upgradeOrConnect) {
     // Server MUST respond with Connection:keep-alive for us to enable it.
     // If we've been upgraded (via WebSockets) we also shouldn't try to
     // keep the connection open.
-    req.shouldKeepAlive = false;
+    if (!shouldKeepAlive) {
+      req.shouldKeepAlive = false;
+    }
+
+    // Socket will be kept alive and response cannot contain
+    // a message body, resume to allow socket to return to free pool
+    else if (responseCannotContainMessageBody(res.statusCode, method)){
+      res.resume()
+    }
   }
 
   if (req[kClientRequestStatistics] && hasObserver('http')) {