fix unicode decode error on windows

pipenv/patched/pip/compat/__init__.py

@@ -4,6 +4,7 @@ from __future__ import absolute_import, division
 
 import os
 import sys
+import locale
 
 from pip._vendor.six import text_type
 
@@ -72,6 +73,10 @@ if sys.version_info >= (3,):
         try:
             return s.decode(sys.__stdout__.encoding)
         except UnicodeDecodeError:
+            if sys.__stdout__.encoding == 'utf-8':
+                encoding = locale.getdefaultlocale()[1]
+                if encoding is not None and encoding.lower() != 'utf-8':
+                    return s.decode(encoding)
             return s.decode('utf_8')
 
     def native_str(s, replace=False):

pipenv/vendor/delegator.py

@@ -2,6 +2,8 @@ import os
 import subprocess
 import shlex
 import signal
+import sys
+import locale
 
 from pexpect.popen_spawn import PopenSpawn
 
@@ -46,9 +48,14 @@ class Command(object):
 
     @property
     def _default_pexpect_kwargs(self):
+        encoding = 'utf-8'
+        if sys.platform == 'win32':
+            default_encoding = locale.getdefaultlocale()[1]
+            if default_encoding is not None:
+                encoding = default_encoding
         return {
             'env': os.environ.copy(),
-            'encoding': 'utf-8',
+            'encoding': encoding,
             'timeout': self.timeout
         }