bpo-37330: open() no longer accept 'U' in file mode (GH-16959)
open(), io.open(), codecs.open() and fileinput.FileInput no longer
accept "U" ("universal newline") in the file mode. This flag was
deprecated since Python 3.3.diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index b37525b..e1638c1 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -712,11 +712,23 @@
self.addCleanup(support.unlink, support.TESTFN)
with open(support.TESTFN, 'wb') as fp:
fp.write(s)
- with support.check_warnings(('', DeprecationWarning)):
- reader = codecs.open(support.TESTFN, 'U', encoding=self.encoding)
- with reader:
+ with codecs.open(support.TESTFN, 'r',
+ encoding=self.encoding) as reader:
self.assertEqual(reader.read(), s1)
+ def test_invalid_modes(self):
+ for mode in ('U', 'rU', 'r+U'):
+ with self.assertRaises(ValueError) as cm:
+ codecs.open(support.TESTFN, mode, encoding=self.encoding)
+ self.assertIn('invalid mode', str(cm.exception))
+
+ for mode in ('rt', 'wt', 'at', 'r+t'):
+ with self.assertRaises(ValueError) as cm:
+ codecs.open(support.TESTFN, mode, encoding=self.encoding)
+ self.assertIn("can't have text and binary mode at once",
+ str(cm.exception))
+
+
class UTF16LETest(ReadTest, unittest.TestCase):
encoding = "utf-16-le"
ill_formed_sequence = b"\x80\xdc"
diff --git a/Lib/test/test_fileinput.py b/Lib/test/test_fileinput.py
index 014f19e..819557d 100644
--- a/Lib/test/test_fileinput.py
+++ b/Lib/test/test_fileinput.py
@@ -226,19 +226,11 @@
self.assertEqual(fi.fileno(), -1)
def test_opening_mode(self):
- try:
- # invalid mode, should raise ValueError
- fi = FileInput(mode="w")
- self.fail("FileInput should reject invalid mode argument")
- except ValueError:
- pass
- # try opening in universal newline mode
- t1 = self.writeTmp(b"A\nB\r\nC\rD", mode="wb")
- with check_warnings(('', DeprecationWarning)):
- fi = FileInput(files=t1, mode="U")
- with check_warnings(('', DeprecationWarning)):
- lines = list(fi)
- self.assertEqual(lines, ["A\n", "B\n", "C\n", "D"])
+ # invalid modes
+ for mode in ('w', 'rU', 'U'):
+ with self.subTest(mode=mode):
+ with self.assertRaises(ValueError):
+ FileInput(mode=mode)
def test_stdin_binary_mode(self):
with mock.patch('sys.stdin') as m_stdin:
@@ -985,10 +977,6 @@
self.assertEqual(lines, expected_lines)
check('r', ['A\n', 'B\n', 'C\n', 'D\u20ac'])
- with self.assertWarns(DeprecationWarning):
- check('rU', ['A\n', 'B\n', 'C\n', 'D\u20ac'])
- with self.assertWarns(DeprecationWarning):
- check('U', ['A\n', 'B\n', 'C\n', 'D\u20ac'])
with self.assertRaises(ValueError):
check('rb', ['A\n', 'B\r\n', 'C\r', 'D\u20ac'])
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 1fe1cba..ad22dfe 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -3886,16 +3886,6 @@
self.assertEqual(f.mode, "wb")
f.close()
- with support.check_warnings(('', DeprecationWarning)):
- f = self.open(support.TESTFN, "U")
- self.assertEqual(f.name, support.TESTFN)
- self.assertEqual(f.buffer.name, support.TESTFN)
- self.assertEqual(f.buffer.raw.name, support.TESTFN)
- self.assertEqual(f.mode, "U")
- self.assertEqual(f.buffer.mode, "rb")
- self.assertEqual(f.buffer.raw.mode, "rb")
- f.close()
-
f = self.open(support.TESTFN, "w+")
self.assertEqual(f.mode, "w+")
self.assertEqual(f.buffer.mode, "rb+") # Does it really matter?
@@ -3909,6 +3899,13 @@
f.close()
g.close()
+ def test_removed_u_mode(self):
+ # "U" mode has been removed in Python 3.9
+ for mode in ("U", "rU", "r+U"):
+ with self.assertRaises(ValueError) as cm:
+ self.open(support.TESTFN, mode)
+ self.assertIn('invalid mode', str(cm.exception))
+
def test_io_after_close(self):
for kwargs in [
{"mode": "w"},