Fix issue #6127: Make universal newlines mode of io.StringIO not
duplicate newlines under Windows (see also issue #5265 and #5645).
diff --git a/Lib/io.py b/Lib/io.py
index 320a4b9..72f7d8c 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -1852,6 +1852,10 @@
encoding=encoding,
errors=errors,
newline=newline)
+ # Issue #5645: make universal newlines semantics the same as in the
+ # C version, even under Windows.
+ if newline is None:
+ self._writetranslate = False
if initial_value:
if not isinstance(initial_value, unicode):
initial_value = unicode(initial_value)