* doc/autoconf.texi (Limitations of Usual Tools) <sed>: Mention the issue. * tests/torture.at (Substitute and define special characters): Detect if sed cannot process 8-bit bytes in the C locale. * THANKS: Update. Reported by Rochan.
Signed-off-by: Eric Blake <ebl...@redhat.com> --- I'm going with this conservative patch prior to the release of 2.68, of declaring MacOS X as XFAIL on this aspect of AC_SUBST. I'm not yet ready to declare that AC_SUBST cannot portably be used with 8-bit bytes, so for now, I'm hoping that at some point post-release, we can find a way to coerce some standard tool on that platform to slice-and-dice arbitrary data in the manner necessary to avoid this awkward regex behavior in the C locale, possibly by probing alternate locale names known to be unibyte until we find a working locale. But waiting for such a fix would needlessly delay the already-long release of 2.68, since most configure scripts don't (ab)use AC_SUBST with 8-bit values, so most users won't notice the limitation. ChangeLog | 10 ++++++++++ THANKS | 1 + doc/autoconf.texi | 22 ++++++++++++++++++++++ tests/torture.at | 3 +++ 4 files changed, 36 insertions(+), 0 deletions(-) diff --git a/ChangeLog b/ChangeLog index 1b47a2c..311f41f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,13 @@ +2010-09-21 Eric Blake <ebl...@redhat.com> + + tests: XFAIL in the face of a MacOS X bug + * doc/autoconf.texi (Limitations of Usual Tools) <sed>: Mention + the issue. + * tests/torture.at (Substitute and define special characters): + Detect if sed cannot process 8-bit bytes in the C locale. + * THANKS: Update. + Reported by Rochan. + 2010-09-20 Eric Blake <ebl...@redhat.com> autom4te: don't filter out portions of location traces diff --git a/THANKS b/THANKS index cb1589b..4acb36f 100644 --- a/THANKS +++ b/THANKS diff --git a/doc/autoconf.texi b/doc/autoconf.texi index 6424302..66d8a21 100644 --- a/doc/autoconf.texi +++ b/doc/autoconf.texi @@ -18700,6 +18700,28 @@ Limitations of Usual Tools not all @command{sed} implementations can handle embedded @code{NUL} or a missing trailing newline. +Remember that ranges within a bracket expression of a regular expression +are only well-defined in the @samp{C} (or @samp{POSIX}) locale. +Meanwhile, support for character classes like @samp{[[:upper:]]} is not +yet universal, so if you cannot guarantee the setting of @env{LC_ALL}, +it is better to spell out a range @samp{[ABCDEFGHIJKLMNOPQRSTUVWXYZ]} +than to rely on @samp{[A-Z]}. + +Additionally, Posix states that regular expressions are only +well-defined on characters. Unfortunately, there exist platforms such +as MacOS X 10.5 where not all 8-bit byte values are valid characters, +even though that platform has a single-byte @samp{C} locale. And Posix +allows the existence of a multi-byte @samp{C} locale, although that does +not yet appear to be a common implementation. At any rate, it means +that not all bytes will be matched by the regular expression @samp{.}: + +...@example +$ @kbd{printf '\200\n' | LC_ALL=C sed -n /./p | wc -l} +0 +$ @kbd{printf '\200\n' | LC_ALL=en_US.ISO8859-1 sed -n /./p | wc -l} +1 +...@end example + Portable @command{sed} regular expressions should use @samp{\} only to escape characters in the string @samp{$()*.0123456789[...@{@}}. For example, alternation, @samp{\|}, is common but Posix does not require its diff --git a/tests/torture.at b/tests/torture.at index 673c7a5..511834d 100644 --- a/tests/torture.at +++ b/tests/torture.at @@ -882,6 +882,9 @@ AT_CLEANUP AT_SETUP([Substitute and define special characters]) AT_KEYWORDS([AC@&t...@_define AC@&t...@_define_unquoted]) +AT_XFAIL_IF([byte=\\200s; dnl +test `{ printf $byte; echo; } | sed -n '/^./p' | wc -l` = 0]) + AT_DATA([Foo.in], [...@foo@ @bar@@notsubsted@@baz@ stray @ and more@@@baz@ a...@bar@b...@baz -- 1.7.2.3