Merged revisions 81758-81759 via svnmerge from

Merged revisions 81758-81759 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r81758 | ezio.melotti | 2010-06-05 20:51:07 +0300 (Sat, 05 Jun 2010) | 15 lines

  Update PyUnicode_DecodeUTF8 from RFC 2279 to RFC 3629.

  1) #8271: when a byte sequence is invalid, only the start byte and all the
     valid continuation bytes are now replaced by U+FFFD, instead of replacing
     the number of bytes specified by the start byte.
     See http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf (pages 94-95);
  2) 5- and 6-bytes-long UTF-8 sequences are now considered invalid (no changes
     in behavior);
  3) Add code and tests to reject surrogates (U+D800-U+DFFF) as defined in
     RFC 3629, but leave it commented out since it's not backward compatible;
  4) Change the error messages "unexpected code byte" to "invalid start byte"
     and "invalid data" to "invalid continuation byte";
  5) Add an extensive set of tests in test_unicode;
  6) Fix test_codeccallbacks because it was failing after this change.
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  r81759 | ezio.melotti | 2010-06-05 22:21:32 +0300 (Sat, 05 Jun 2010) | 1 line

  Add a NEWS entry for r81758 and clarify a comment.
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