On 25/07/10 10:16PM, brian m. carlson wrote:
> The LANGUAGE environment variable is not specified by POSIX, but a
> variety of programs using GNU gettext accept it. The Linux manpages
> state that it can contain a colon-separated list of locales.
>
> However, not all locales are valid as languages. The C and POSIX
> locales, for instance, are not languages and are not registered with
> IANA, nor are they a part of ISO 639. In fact, "C" is too short to
> match the ABNF production for a language, which must be at least two
> characters in length.
>
> Nonetheless, many users provide these values in the LANGUAGE environment
> variable for unknown reasons and if they do, we do not want to send a
> malformed Accept-Language header to the server. If there are no other
> valid language tags, then send no header; otherwise, send only the valid
> tags, ignoring "C" and "POSIX" wherever they may appear, as well as any
> variants (such as the "C.UTF-8" locale found on some Linux systems).
Ok so the languages returned by `get_preferred_languages()` are used to
write the Accept-Language header when making requests.
Looking at `get_preferred_languages()` when NO_GETTEXT is defined, we
already filter out "C" and "POSIX". So doing this for the LANGUAGE
environment variable when writing the header also makes sense.
> We do not reject all possible invalid language tags since doing so
> would require bundling a copy of the IANA database and would risk poor
> behavior in the face of uncommon languages or values that are not
> registered but meet the production for private use or other restricted
> interchange. However, these two values are widely used in the LANGUAGE
> header, are well-known and widely used non-language locales, and have
> been seen in the wild on the server side.
>
> Signed-off-by: brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx>
> ---
> http.c | 8 ++++++++
> t/t5541-http-push-smart.sh | 18 ++++++++++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/http.c b/http.c
> index d88e79fbde..a96df4fcdb 100644
> --- a/http.c
> +++ b/http.c
> @@ -2022,6 +2022,14 @@ static void write_accept_language(struct strbuf *buf)
> s++;
>
> if (tag.len) {
> + /*
> + * These are not valid languages: do not send them to
> + * the server.
> + */
> + if (!strcmp(tag.buf, "C") || !strcmp(tag.buf, "POSIX")) {
> + strbuf_reset(&tag);
> + continue;
> + }
