Here is a report from a GNU sed user. Paolo
> SETUP: > $ sw_vers > ProductName: Mac OS X > ProductVersion: 10.7.4 > BuildVersion: 11E53 > > $ ~/gnu/bin/sed --version > GNU sed version 4.2.1 > > PROBLEM: With UTF-8 input, but LANG and LC_ALL set to C, sed regular > expressions break on multibyte sequences. For example (constructed > from part of a git command): > > $ echo "Rémi Leblond" | LANG=C LC_ALL=C ~/gnu/bin/sed -ne > 's/.*/GIT_AUTHOR_NAME='\''&'\''/p' > > EXPECTED: GIT_AUTHOR_NAME='Rémi Leblond' > ACTUAL: GIT_AUTHOR_NAME='R'émi Leblond > > DISCUSSION: The problem starts in sed/lib/localcharset.c, > locale_charset, line 334 > > # if HAVE_LANGINFO_CODESET > > /* Most systems support nl_langinfo (CODESET) nowadays. */ > codeset = nl_langinfo (CODESET); > > Since we set LC_ALL to C, we trigger this code in Libc: > > http://www.opensource.apple.com/source/Libc/Libc-763.13/locale/nl_langinfo-fbsd.c, > line 54: > > case CODESET: > ret = ""; > if ((s = querylocale(LC_CTYPE_MASK, loc)) != NULL) { > if ((cs = strchr(s, '.')) != NULL) > ret = cs + 1; > else if (strcmp(s, "C") == 0 || > strcmp(s, "POSIX") == 0) > ret = "US-ASCII"; > else if (strcmp(s, "UTF-8") == 0) > ret = "UTF-8"; > } > break; > > As you can see, querylocale() will return "C", and > nl_langinfo(CODESET) will return "US-ASCII". The other thing to > realize is that on OS X MB_CUR_MAX is a macro for ___mb_cur_max(), > which returns 1 when LC_ALL is C. > > Back to sed/lib/localcharset.c, we end up at locale_charset(), line 483: > > /* Resolve alias. */ > for (aliases = get_charset_aliases (); > *aliases != '\0'; > aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1) > if (strcmp (codeset, aliases) == 0 > || (aliases[0] == '*' && aliases[1] == '\0')) > { > codeset = aliases + strlen (aliases) + 1; > break; > } > > This tries to alias our charset, "US-ASCII", to something sed > understands. get_charset_aliases() is at line 112 in the same file. On > OS X 10.7, DARWIN7 is defined (always for OS X 10.3 or newer), so we > end up at line 223: > > /* To avoid the trouble of installing a file that is shared by many > GNU packages -- many packaging systems have problems with this --, > simply inline the aliases here. */ > cp = "ISO8859-1" "\0" "ISO-8859-1" "\0" > "ISO8859-2" "\0" "ISO-8859-2" "\0" > "ISO8859-4" "\0" "ISO-8859-4" "\0" > "ISO8859-5" "\0" "ISO-8859-5" "\0" > "ISO8859-7" "\0" "ISO-8859-7" "\0" > "ISO8859-9" "\0" "ISO-8859-9" "\0" > "ISO8859-13" "\0" "ISO-8859-13" "\0" > "ISO8859-15" "\0" "ISO-8859-15" "\0" > "KOI8-R" "\0" "KOI8-R" "\0" > "KOI8-U" "\0" "KOI8-U" "\0" > "CP866" "\0" "CP866" "\0" > "CP949" "\0" "CP949" "\0" > "CP1131" "\0" "CP1131" "\0" > "CP1251" "\0" "CP1251" "\0" > "eucCN" "\0" "GB2312" "\0" > "GB2312" "\0" "GB2312" "\0" > "eucJP" "\0" "EUC-JP" "\0" > "eucKR" "\0" "EUC-KR" "\0" > "Big5" "\0" "BIG5" "\0" > "Big5HKSCS" "\0" "BIG5-HKSCS" "\0" > "GBK" "\0" "GBK" "\0" > "GB18030" "\0" "GB18030" "\0" > "SJIS" "\0" "SHIFT_JIS" "\0" > "ARMSCII-8" "\0" "ARMSCII-8" "\0" > "PT154" "\0" "PT154" "\0" > /*"ISCII-DEV" "\0" "?" "\0"*/ > "*" "\0" "UTF-8" "\0"; > > And here is the root problem. This table does not have an entry for > US-ASCII. So it catches the default entry, "*", which maps everything > to "UTF-8", and that's what get_charset_aliases() returns, and what > locale_charset(), which then sets a UTF-8 flag in sed that gets used > by many parts. > > But this is dangerous, because now UTF-8 is set but MB_CUR_MAX is 1 > and various parts of sed interpret "Rémi Leblond" as an invalid > character sequence for a UTF-8 character set. This is why /.*/ in the > regular expression only matches the "R" before bailing on the "é". > > POSIX says that the "C" locale should treat text data is binary input, > but in this situation sed is trying to treat it as a multibyte > encoding. > > FIX: the DARWIN7 table in get_charset_aliases() should not contain a > default that maps everything not defined to "UTF-8". Or at the very > least, it should include an entry for "US-ASCII" that maps to "ASCII", > as a charset.aliases file might. >
