Force use of backports.typing in python < 3.6

Makefile

@@ -14,14 +14,15 @@ install:
 test:
 	$(TEST)
 
+clean:
+	rm -Rf __pycache__
+	rm -Rf **/__pycache__/*
+	rm -Rf dist
+	rm -Rf build
+	rm -Rf *.egg-info
+
 release:
-	# make sure required variables set via commandline
-	ifndef version
-		$(error version is not set)
-	endif
-	ifndef token
-		$(error token is not set)
-	endif
+	$(clean)
 	# tag
 	git tag $(version)
 	# build

setup.py

@@ -6,9 +6,11 @@
 if sys.version_info < (3, 3):
     sys.stdout.write("At least Python 3.3 is required.\n")
     sys.exit(1)
-elif sys.version_info < (3, 5):
-    # typing was added in 3.5, but a backport is available for 3.3+
-    requirements.append('typing')
+elif sys.version_info < (3, 6):
+    # typing was added in 3.5, and we rely on critical features that were
+    # introduced in 3.5.2+, so for versions older than 3.6 we rely on
+    # a backport
+    requirements.append('backports.typing')
 
 import versioneer
 
@@ -30,9 +32,11 @@
         'Topic :: Software Development :: Libraries :: Python Modules',
         'License :: MIT',
         'License :: Public Domain',
+        'Programming Language :: Python :: 3 :: Only',
         'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
-        'Programming Language :: Python :: 3.6'
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.6',
     ],
 )

xphyle/types.py

@@ -9,10 +9,17 @@
 import stat
 import sys
 from types import ModuleType
-from typing import *
-# ISSUE: Not sure why I have to import IO separately
-from typing import IO
-from typing.re import *
+# HACK: critical features were introduced in python 3.5.2, so we force use
+# of backports.typing even in 3.5
+if sys.version_info < (3, 6):
+    from backports.typing import *
+    from backports.typing import IO
+    from backports.typing.re import *
+else:
+    from typing import *
+    # ISSUE: Not sure why I have to import IO separately
+    from typing import IO
+    from typing.re import *
 
 # ISSUE: there are several mypy errors due to incomplete enum support.
 # enums should be fully suported in the next version of mypy (>0.501).