http: send implicit headers on HEAD with no body

lib/_http_outgoing.js

@@ -887,17 +887,6 @@ function write_(msg, chunk, encoding, callback, fromEnd) {
     err = new ERR_STREAM_DESTROYED('write');
   }
 
-  if (!msg._hasBody) {
-    if (msg[kRejectNonStandardBodyWrites]) {
-      throw new ERR_HTTP_BODY_NOT_ALLOWED();
-    } else {
-      debug('This type of response MUST NOT have a body. ' +
-        'Ignoring write() calls.');
-      process.nextTick(callback);
-      return true;
-    }
-  }
-
   if (err) {
     if (!msg.destroyed) {
       onError(msg, err, callback);
@@ -930,6 +919,17 @@ function write_(msg, chunk, encoding, callback, fromEnd) {
     msg._implicitHeader();
   }
 
+  if (!msg._hasBody) {
+    if (msg[kRejectNonStandardBodyWrites]) {
+      throw new ERR_HTTP_BODY_NOT_ALLOWED();
+    } else {
+      debug('This type of response MUST NOT have a body. ' +
+        'Ignoring write() calls.');
+      process.nextTick(callback);
+      return true;
+    }
+  }
+
   if (!fromEnd && msg.socket && !msg.socket.writableCorked) {
     msg.socket.cork();
     process.nextTick(connectionCorkNT, msg.socket);

test/parallel/test-http-head-response-has-no-body-end-implicit-headers.js

@@ -0,0 +1,48 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+const common = require('../common');
+const http = require('http');
+
+// This test is to make sure that when the HTTP server
+// responds to a HEAD request with data to res.end,
+// it does not send any body but the response is sent
+// anyway.
+
+const server = http.createServer(function(req, res) {
+  res.end('FAIL'); // broken: sends FAIL from hot path.
+});
+server.listen(0);
+
+server.on('listening', common.mustCall(function() {
+  const req = http.request({
+    port: this.address().port,
+    method: 'HEAD',
+    path: '/'
+  }, common.mustCall(function(res) {
+    res.on('end', common.mustCall(function() {
+      server.close();
+    }));
+    res.resume();
+  }));
+  req.end();
+}));

test/parallel/test-http-head-response-has-no-body-end.js

@@ -29,7 +29,7 @@ const http = require('http');
 
 const server = http.createServer(function(req, res) {
   res.writeHead(200);
-  res.end();
+  res.end('FAIL'); // broken: sends FAIL from hot path.
 });
 server.listen(0);