net: Socket write encoding case sensitivity

Fixes #1586.

lib/net.js

@@ -409,16 +409,10 @@ Socket.prototype._writeOut = function(data, encoding, fd, cb) {
       allocNewPool();
     }
 
-    if (!encoding || encoding == 'utf8' || encoding == 'utf-8') {
-      // default to utf8
-      bytesWritten = pool.write(data, 'utf8', pool.used);
-      charsWritten = Buffer._charsWritten;
-    } else {
-      bytesWritten = pool.write(data, encoding, pool.used);
-      charsWritten = bytesWritten;
-    }
+    bytesWritten = pool.write(data, encoding, pool.used);
+    charsWritten = Buffer._charsWritten;
 
-    if (encoding && data.length > 0) {
+    if (data.length > 0) {
       assert(bytesWritten > 0);
     }
 

test/simple/test-net-large-string.js

@@ -0,0 +1,55 @@
+// 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.
+
+var common = require('../common');
+var assert = require('assert');
+var net = require('net');
+
+var kPoolSize = 40 * 1024;
+var data = '';
+for (var i = 0; i < kPoolSize; ++i) {
+  data += 'あ'; // 3bytes
+}
+var receivedSize = 0;
+var encoding = 'UTF-8';
+
+var server = net.createServer(function(socket) {
+  socket.setEncoding(encoding);
+  socket.on('data', function(data) {
+    receivedSize += data.length;
+  });
+  socket.on('end', function() {
+    socket.end();
+  });
+});
+
+server.listen(common.PORT, function() {
+  var client = net.createConnection(common.PORT);
+  client.on('end', function() {
+    server.close();
+  });
+  client.write(data, encoding);
+  client.end();
+});
+
+process.on('exit', function() {
+  assert.equal(receivedSize, kPoolSize);
+});