Issue #21171: Fixed undocumented filter API of the rot13 codec.

Patch by Berker Peksag.

Lib/encodings/rot_13.py

@@ -106,7 +106,7 @@ rot13_map.update({
 ### Filter API
 
 def rot13(infile, outfile):
-    outfile.write(infile.read().encode('rot-13'))
+    outfile.write(codecs.encode(infile.read(), 'rot-13'))
 
 if __name__ == '__main__':
     import sys

Misc/NEWS

@@ -34,6 +34,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #21171: Fixed undocumented filter API of the rot13 codec.
+  Patch by Berker Peksag.
+
 - Issue #20539: Improved math.factorial error message for large positive inputs
   and changed exception type (OverflowError -> ValueError) for large negative
   inputs.