Use pathlib2 for Path objects on Python < 3.4

The pathlib backport module is no longer maintained. The development
has moved to the pathlib2 module instead.

Quoting from the pathlib's README:
"Attention: this backport module isn't maintained anymore. If you want
to report issues or contribute patches, please consider the pathlib2
project instead."

Other projects have already switched to pathlib2, most notably IPython
and its dependencies.

PIL/Image.py

@@ -132,6 +132,16 @@ try:
 except ImportError:
     HAS_CFFI = False
 
+try:
+    from pathlib import Path
+    HAS_PATHLIB = True
+except ImportError:
+    try:
+        from pathlib2 import Path
+        HAS_PATHLIB = True
+    except ImportError:
+        HAS_PATHLIB = False
+
 
 def isImageType(t):
     """
@@ -1652,11 +1662,9 @@ class Image(object):
         if isPath(fp):
             filename = fp
             open_fp = True
-        elif sys.version_info >= (3, 4):
-            from pathlib import Path
-            if isinstance(fp, Path):
-                filename = str(fp)
-                open_fp = True
+        elif HAS_PATHLIB and isinstance(fp, Path):
+            filename = str(fp)
+            open_fp = True
         if not filename and hasattr(fp, "name") and isPath(fp.name):
             # only set the name for metadata purposes
             filename = fp.name
@@ -2267,13 +2275,8 @@ def open(fp, mode="r"):
     filename = ""
     if isPath(fp):
         filename = fp
-    else:
-        try:
-            from pathlib import Path
-            if isinstance(fp, Path):
-                filename = str(fp.resolve())
-        except ImportError:
-            pass
+    elif HAS_PATHLIB and isinstance(fp, Path):
+        filename = str(fp.resolve())
 
     if filename:
         fp = builtins.open(filename, "rb")

Tests/test_image.py

@@ -2,7 +2,6 @@ from helper import unittest, PillowTestCase, hopper
 
 from PIL import Image
 import os
-import sys
 
 
 class TestImage(PillowTestCase):
@@ -50,10 +49,9 @@ class TestImage(PillowTestCase):
             im = io.BytesIO(b'')
         self.assertRaises(IOError, lambda: Image.open(im))
 
-    @unittest.skipIf(sys.version_info < (3, 4),
-                     "pathlib only available in Python 3.4 or later")
+    @unittest.skipUnless(Image.HAS_PATHLIB, "requires pathlib/pathlib2")
     def test_pathlib(self):
-        from pathlib import Path
+        from PIL.Image import Path
         im = Image.open(Path("Tests/images/hopper.jpg"))
         self.assertEqual(im.mode, "RGB")
         self.assertEqual(im.size, (128, 128))