Merged revisions 78461,78482 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r78461 | florent.xicluna | 2010-02-26 11:40:58 +0100 (ven, 26 fév 2010) | 2 lines

  #691291: codecs.open() should not convert end of lines on reading and writing.
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  r78482 | florent.xicluna | 2010-02-27 12:19:18 +0100 (sam, 27 fév 2010) | 2 lines

  Add entry for issue #691291.
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diff --git a/Lib/codecs.py b/Lib/codecs.py
index 557ccf7..a67240a 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -858,10 +858,15 @@
         parameter.
 
     """
-    if encoding is not None and \
-       'b' not in mode:
-        # Force opening of the file in binary mode
-        mode = mode + 'b'
+    if encoding is not None:
+        if 'U' in mode:
+            # No automatic conversion of '\n' is done on reading and writing
+            mode = mode.strip().replace('U', '')
+            if mode[:1] not in set('rwa'):
+                mode = 'r' + mode
+        if 'b' not in mode:
+            # Force opening of the file in binary mode
+            mode = mode + 'b'
     file = __builtin__.open(filename, mode, buffering)
     if encoding is None:
         return file