next.js/patches/http-proxy@1.18.1.patch

diff --git a/lib/http-proxy/common.js b/lib/http-proxy/common.js
index 6513e81d80d5250ea249ea833f819ece67897c7e..09143dd1fe4e67885f40ea916a6ea1ef3e3afa19 100644
--- a/lib/http-proxy/common.js
+++ b/lib/http-proxy/common.js
@@ -1,9 +1,9 @@
 var common   = exports,
     url      = require('url'),
-    extend   = require('util')._extend,
     required = require('requires-port');
 
 var upgradeHeader = /(^|,)\s*upgrade\s*($|,)/i,
+    hopByHopTransferEncodingHeader = /(^|,)\s*transfer-encoding\s*($|,)/i,
     isSSL = /^https|wss/;
 
 /**
@@ -40,10 +40,10 @@ common.setupOutgoing = function(outgoing, options, req, forward) {
   );
 
   outgoing.method = options.method || req.method;
-  outgoing.headers = extend({}, req.headers);
+  outgoing.headers = Object.assign({}, req.headers);
 
   if (options.headers){
-    extend(outgoing.headers, options.headers);
+    Object.assign(outgoing.headers, options.headers);
   }
 
   if (options.auth) {
@@ -61,13 +61,22 @@ common.setupOutgoing = function(outgoing, options, req, forward) {
 
   outgoing.agent = options.agent || false;
   outgoing.localAddress = options.localAddress;
+  outgoing.headers = outgoing.headers || {};
+  var hasTransferEncodingHeader = Object.keys(outgoing.headers).some(function (header) {
+    return header.toLowerCase() === 'transfer-encoding'
+      && typeof outgoing.headers[header] !== 'undefined';
+  });
+
+  if (hasTransferEncodingHeader
+      || (typeof outgoing.headers.connection === 'string'
+          && hopByHopTransferEncodingHeader.test(outgoing.headers.connection))
+     ) { outgoing.headers.connection = 'close'; }
 
   //
   // Remark: If we are false and not upgrading, set the connection: close. This is the right thing to do
   // as node core doesn't handle this COMPLETELY properly yet.
   //
   if (!outgoing.agent) {
-    outgoing.headers = outgoing.headers || {};
     if (typeof outgoing.headers.connection !== 'string'
         || !upgradeHeader.test(outgoing.headers.connection)
        ) { outgoing.headers.connection = 'close'; }
diff --git a/lib/http-proxy/index.js b/lib/http-proxy/index.js
index 977a4b3622b9eaac27689f06347ea4c5173a96cd..88b2d0fcfa03c3aafa47c7e6d38e64412c45a7cc 100644
--- a/lib/http-proxy/index.js
+++ b/lib/http-proxy/index.js
@@ -1,5 +1,4 @@
 var httpProxy = module.exports,
-    extend    = require('util')._extend,
     parse_url = require('url').parse,
     EE3       = require('eventemitter3'),
     http      = require('http'),
@@ -47,9 +46,9 @@ function createRightProxy(type) {
         args[cntr] !== res
       ) {
         //Copy global options
-        requestOptions = extend({}, options);
+        requestOptions = Object.assign({}, options);
         //Overwrite with request options
-        extend(requestOptions, args[cntr]);
+        Object.assign(requestOptions, args[cntr]);
 
         cntr--;
       }
diff --git a/lib/http-proxy/passes/web-incoming.js b/lib/http-proxy/passes/web-incoming.js
index 7ae735514190eea569c605fff7d27c045fe8d601..c7c25e7228b21c76b3c7115af82ddcbf13a8e3ec 100644
--- a/lib/http-proxy/passes/web-incoming.js
+++ b/lib/http-proxy/passes/web-incoming.js
@@ -33,9 +33,9 @@ module.exports = {
 
   deleteLength: function deleteLength(req, res, options) {
     if((req.method === 'DELETE' || req.method === 'OPTIONS')
-       && !req.headers['content-length']) {
+       && typeof req.headers['content-length'] === 'undefined'
+       && typeof req.headers['transfer-encoding'] === 'undefined') {
       req.headers['content-length'] = '0';
-      delete req.headers['transfer-encoding'];
     }
   },