Issue #22413: Merge StringIO doc from 3.4 into 3.5

1 files changed, 5 insertions, 2 deletions

diff --git a/Lib/xml/sax/saxutils.py b/Lib/xml/sax/saxutils.py
index 1d3d0ecc5f..a69c7f7621 100644
--- a/Lib/xml/sax/saxutils.py
+++ b/Lib/xml/sax/saxutils.py
@@ -345,11 +345,14 @@ def prepare_input_source(source, base=""):
     elif hasattr(source, "read"):
         f = source
         source = xmlreader.InputSource()
-        source.setByteStream(f)
+        if isinstance(f.read(0), str):
+            source.setCharacterStream(f)
+        else:
+            source.setByteStream(f)
         if hasattr(f, "name") and isinstance(f.name, str):
             source.setSystemId(f.name)
 
-    if source.getByteStream() is None:
+    if source.getCharacterStream() is None and source.getByteStream() is None:
         sysid = source.getSystemId()
         basehead = os.path.dirname(os.path.normpath(base))
         sysidfilename = os.path.join(basehead, sysid)