bpo-31966: Fixed WindowsConsoleIO.write() for writing empty data. (GH-5754)

miss-islington · serhiy-storchaka · web-flow · commit 980790eee0c8 · 2018-02-24T09:43:05.000-08:00
(cherry picked from commit 42c35d9) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Lib/test/test_winconsoleio.py b/Lib/test/test_winconsoleio.py
@@ -121,6 +121,10 @@ def test_conout_path(self):
             else:
                 self.assertNotIsInstance(f, ConIO)
 
+    def test_write_empty_data(self):
+        with ConIO('CONOUT$', 'w') as f:
+            self.assertEqual(f.write(b''), 0)
+
     def assertStdinRoundTrip(self, text):
         stdin = open('CONIN$', 'r')
         old_stdin = sys.stdin
diff --git a/Misc/NEWS.d/next/Windows/2018-02-19-13-54-42.bpo-31966._Q3HPb.rst b/Misc/NEWS.d/next/Windows/2018-02-19-13-54-42.bpo-31966._Q3HPb.rst
@@ -0,0 +1 @@
+Fixed WindowsConsoleIO.write() for writing empty data.
diff --git a/Modules/_io/winconsoleio.c b/Modules/_io/winconsoleio.c
@@ -981,6 +981,9 @@ _io__WindowsConsoleIO_write_impl(winconsoleio *self, Py_buffer *b)
     if (!self->writable)
         return err_mode("writing");
 
+    if (!b->len) {
+        return PyLong_FromLong(0);
+    }
     if (b->len > BUFMAX)
         len = BUFMAX;
     else

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Fixed WindowsConsoleIO.write() for writing empty data.`