From 41b81af11b82132e8e37819929da47f8971dd54e Mon Sep 17 00:00:00 2001
From: Yuhong Guo <guoyuhong1985@outlook.com>
Date: Thu, 28 Feb 2019 05:05:25 +0800
Subject: [PATCH] Downgrade six to 1.0.0 (#4180)

---
 python/ray/function_manager.py | 14 +++++++-------
 python/ray/utils.py            | 32 ++++++++++++++++++++++++++++++++
 python/setup.py                |  4 +++-
 3 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/python/ray/function_manager.py b/python/ray/function_manager.py
index 814fe4cd9..bc63a994f 100644
--- a/python/ray/function_manager.py
+++ b/python/ray/function_manager.py
@@ -7,7 +7,6 @@ import importlib
 import inspect
 import json
 import logging
-import six
 import sys
 import time
 import traceback
@@ -27,6 +26,7 @@ from ray.utils import (
     is_class_method,
     check_oversized_pickle,
     decode,
+    ensure_str,
     format_error_message,
     push_error_to_driver,
 )
@@ -89,9 +89,9 @@ class FunctionDescriptor(object):
             return FunctionDescriptor.for_driver_task()
         elif (len(function_descriptor_list) == 3
               or len(function_descriptor_list) == 4):
-            module_name = six.ensure_str(function_descriptor_list[0])
-            class_name = six.ensure_str(function_descriptor_list[1])
-            function_name = six.ensure_str(function_descriptor_list[2])
+            module_name = ensure_str(function_descriptor_list[0])
+            class_name = ensure_str(function_descriptor_list[1])
+            function_name = ensure_str(function_descriptor_list[2])
             if len(function_descriptor_list) == 4:
                 return cls(module_name, function_name, class_name,
                            function_descriptor_list[3])
@@ -709,10 +709,10 @@ class FunctionActorManager(object):
                  "actor_method_names"
              ])
 
-        class_name = six.ensure_str(class_name)
-        module_name = six.ensure_str(module)
+        class_name = ensure_str(class_name)
+        module_name = ensure_str(module)
         driver_id = ray.DriverID(driver_id_str)
-        actor_method_names = json.loads(six.ensure_str(actor_method_names))
+        actor_method_names = json.loads(ensure_str(actor_method_names))
 
         actor_class = None
         try:
diff --git a/python/ray/utils.py b/python/ray/utils.py
index d80e10f79..106c472a0 100644
--- a/python/ray/utils.py
+++ b/python/ray/utils.py
@@ -10,6 +10,7 @@ import inspect
 import logging
 import numpy as np
 import os
+import six
 import subprocess
 import sys
 import threading
@@ -180,6 +181,37 @@ def decode(byte_str, allow_none=False):
         return byte_str
 
 
+def ensure_str(s, encoding="utf-8", errors="strict"):
+    """Coerce *s* to `str`.
+
+    To keep six with lower version, see Issue 4169, we copy this function
+    from six == 1.12.0.
+
+    TODO(yuhguo): remove this function when six >= 1.12.0.
+
+    For Python 2:
+      - `unicode` -> encoded to `str`
+      - `str` -> `str`
+
+    For Python 3:
+      - `str` -> `str`
+      - `bytes` -> decoded to `str`
+    """
+    if six.PY3:
+        text_type = str
+        binary_type = bytes
+    else:
+        text_type = unicode  # noqa: F821
+        binary_type = str
+    if not isinstance(s, (text_type, binary_type)):
+        raise TypeError("not expecting type '%s'" % type(s))
+    if six.PY2 and isinstance(s, text_type):
+        s = s.encode(encoding, errors)
+    elif six.PY3 and isinstance(s, binary_type):
+        s = s.decode(encoding, errors)
+    return s
+
+
 def binary_to_object_id(binary_object_id):
     return ray.ObjectID(binary_object_id)
 
diff --git a/python/setup.py b/python/setup.py
index 4b9a650b4..6cb9f2d2b 100644
--- a/python/setup.py
+++ b/python/setup.py
@@ -152,7 +152,9 @@ requires = [
     "pytest",
     "pyyaml",
     "redis",
-    "six >= 1.12.0",
+    # NOTE: Don't upgrade the version of six! Doing so causes installation
+    # problems. See https://github.com/ray-project/ray/issues/4169.
+    "six >= 1.0.0",
     # The typing module is required by modin.
     "typing",
     "flatbuffers",