bpo-38971: Open file in codecs.open() closes if exception raised. (GH-17666)
Open issue in the BPO indicated a desire to make the implementation of
codecs.open() at parity with io.open(), which implements a try/except to
assure file stream gets closed before an exception is raised.
diff --git a/Lib/codecs.py b/Lib/codecs.py
index 21c45a7..7f23e97 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -905,11 +905,16 @@
file = builtins.open(filename, mode, buffering)
if encoding is None:
return file
- info = lookup(encoding)
- srw = StreamReaderWriter(file, info.streamreader, info.streamwriter, errors)
- # Add attributes to simplify introspection
- srw.encoding = encoding
- return srw
+
+ try:
+ info = lookup(encoding)
+ srw = StreamReaderWriter(file, info.streamreader, info.streamwriter, errors)
+ # Add attributes to simplify introspection
+ srw.encoding = encoding
+ return srw
+ except:
+ file.close()
+ raise
def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'):
diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index 8d9cb90..dcdd574 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -1154,6 +1154,7 @@
got = ostream.getvalue()
self.assertEqual(got, unistring)
+
class EscapeDecodeTest(unittest.TestCase):
def test_empty(self):
self.assertEqual(codecs.escape_decode(b""), (b"", 0))
@@ -1725,6 +1726,14 @@
self.assertRaises(UnicodeError,
codecs.decode, b'abc', 'undefined', errors)
+ def test_file_closes_if_lookup_error_raised(self):
+ mock_open = mock.mock_open()
+ with mock.patch('builtins.open', mock_open) as file:
+ with self.assertRaises(LookupError):
+ codecs.open(support.TESTFN, 'wt', 'invalid-encoding')
+
+ file().close.assert_called()
+
class StreamReaderTest(unittest.TestCase):