New submission from Ezio Melotti <ezio.melo...@gmail.com>: >From Chapter 03 of the Unicode Standard 6[0], D91: """ • UTF-16 encoding form: The Unicode encoding form that assigns each Unicode scalar value in the ranges U+0000..U+D7FF and U+E000..U+FFFF to a single unsigned 16-bit code unit with the same numeric value as the Unicode scalar value, and that assigns each Unicode scalar value in the range U+10000..U+10FFFF to a surrogate pair, according to Table 3-5. • Because surrogate code points are not Unicode scalar values, isolated UTF-16 code units in the range 0xD800..0xDFFF are ill-formed. """ I.e. UTF-16 should be able to decode correctly a valid surrogate pair, and encode a non-BMP character using a valid surrogate pair, but it should reject lone surrogates both during encoding and decoding.
On Python 3, the utf-16 codec can encode all the codepoints from U+0000 to U+10FFFF (including (lone) surrogates), but it's not able to decode lone surrogates (not sure if this is by design or if it just fails because it expects another (missing) surrogate). ---------------------------------------------- >From Chapter 03 of the Unicode Standard 6[0], D90: """ • UTF-32 encoding form: The Unicode encoding form that assigns each Unicode scalar value to a single unsigned 32-bit code unit with the same numeric value as the Unicode scalar value. • Because surrogate code points are not included in the set of Unicode scalar values, UTF-32 code units in the range 0x0000D800..0x0000DFFF are ill-formed. """ I.e. UTF-32 should reject both lone surrogates and valid surrogate pairs, both during encoding and during decoding. On Python 3, the utf-32 codec can encode and decode all the codepoints from U+0000 to U+10FFFF (including surrogates). ---------------------------------------------- I think that: * this should be fixed in 3.3; * it's a bug, so the fix /might/ be backported to 3.2. Hoverver it's also a fairly big change in behavior, so it might be better to leave it for 3.3 only; * it's better to leave 2.7 alone, even the utf-8 codec is broken there; * the surrogatepass error handler should work with the utf-16 and utf-32 codecs too. Note that this has been already reported in #3672, but eventually only the utf-8 codec was fixed. [0]: http://www.unicode.org/versions/Unicode6.0.0/ch03.pdf ---------- assignee: ezio.melotti components: Unicode messages: 143490 nosy: ezio.melotti, gvanrossum, haypo, lemburg, loewis, tchrist priority: high severity: normal stage: test needed status: open title: UTF-16 and UTF-32 codecs should reject (lone) surrogates type: behavior versions: Python 3.3 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue12892> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
