bpo-35062: Fix parsing _io.IncrementalNewlineDecoder's *translate* argument. (GH-10217)

_io.IncrementalNewlineDecoder's initializer possibly assigns out-of-range
value to the bitwise struct field.

1 files changed, 10 insertions, 0 deletions

diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index abd55387bd..d927bb96ce 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -3748,6 +3748,16 @@ class IncrementalNewlineDecoderTest(unittest.TestCase):
         dec = self.IncrementalNewlineDecoder(None, translate=True)
         _check(dec)
 
+    def test_translate(self):
+        # issue 35062
+        for translate in (-2, -1, 1, 2):
+            decoder = codecs.getincrementaldecoder("utf-8")()
+            decoder = self.IncrementalNewlineDecoder(decoder, translate)
+            self.check_newline_decoding_utf8(decoder)
+        decoder = codecs.getincrementaldecoder("utf-8")()
+        decoder = self.IncrementalNewlineDecoder(decoder, translate=0)
+        self.assertEqual(decoder.decode(b"\r\r\n"), "\r\r\n")
+
 class CIncrementalNewlineDecoderTest(IncrementalNewlineDecoderTest):
     pass