don't accept bytes in FileIO.write #7785

Lib/test/test_fileio.py

@@ -78,6 +78,9 @@ class AutoFileTests(unittest.TestCase):
         self.assertEqual(self.f.readline(None), b"hi\n")
         self.assertEqual(self.f.readlines(None), [b"bye\n", b"abc"])
 
+    def test_reject(self):
+        self.assertRaises(TypeError, self.f.write, "Hello!")
+
     def testRepr(self):
         self.assertEquals(repr(self.f), "<_io.FileIO name=%r mode=%r>"
                                         % (self.f.name, self.f.mode))
@@ -168,7 +171,7 @@ class AutoFileTests(unittest.TestCase):
 
     @ClosedFDRaises
     def testErrnoOnClosedWrite(self, f):
-        f.write('a')
+        f.write(b'a')
 
     @ClosedFDRaises
     def testErrnoOnClosedSeek(self, f):

Misc/NEWS

@@ -234,6 +234,8 @@ C-API
 Library
 -------
 
+- Don't accept bytes in FileIO.write().
+
 - Removed the functions 'verify' and 'vereq' from Lib/test/support.py.
 
 - Issue #7773: Fix an UnboundLocalError in platform.linux_distribution() when

Modules/_io/fileio.c

@@ -648,7 +648,7 @@ fileio_write(fileio *self, PyObject *args)
 	if (!self->writable)
 		return err_mode("writing");
 
-	if (!PyArg_ParseTuple(args, "s*", &pbuf))
+	if (!PyArg_ParseTuple(args, "y*", &pbuf))
 		return NULL;
 
 	if (_PyVerify_fd(self->fd)) {