Use io.open() to avoid deprecation warning about 'U' mode

Use io.open() which has a consistent interface between Python 2 and Python 3.
In particular, `newline` parameter is meant to control "universal new lines"
and it is None by default so we don't need to specify it.

2 files changed, 4 insertions, 2 deletions

diff --git a/logilab/common/fileutils.py b/logilab/common/fileutils.py
index 366d23d..48828fb 100644
--- a/logilab/common/fileutils.py
+++ b/logilab/common/fileutils.py
@@ -28,6 +28,7 @@ from __future__ import print_function
 
 __docformat__ = "restructuredtext en"
 
+import io
 import sys
 import shutil
 import mimetypes
@@ -282,7 +283,7 @@ def lines(path, comments=None):
 
     :warning: at some point this function will probably return an iterator
     """
-    stream = open(path, 'U')
+    stream = io.open(path)
     result = stream_lines(stream, comments)
     stream.close()
     return result
diff --git a/test/unittest_fileutils.py b/test/unittest_fileutils.py
index 80cefe4..a43b60f 100644
--- a/test/unittest_fileutils.py
+++ b/test/unittest_fileutils.py
@@ -18,6 +18,7 @@
 """unit tests for logilab.common.fileutils"""
 
 import doctest
+import io
 import sys, os, tempfile, shutil
 from stat import S_IWRITE
 from os.path import join
@@ -54,7 +55,7 @@ class GetModeTC(TestCase):
 
 class NormReadTC(TestCase):
     def test_known_values_norm_read(self):
-        data = open(NEWLINES_TXT, 'U').read()
+        data = io.open(NEWLINES_TXT).read()
         self.assertEqual(data.strip(), '\n'.join(['# mixed new lines', '1', '2', '3']))