bug#51011: [GNU sort] Numerical sort with delimiter may be broken (bug)

[Paul Eggert]

On 10/4/21 08:58, Pádraig Brady wrote:
> The --debug option points out the issue:
>
>    $ printf '%s\n' 1,a 0,9 | sort --debug -nk1 -t ,
>    sort: key 1 is numeric and spans multiple fields
>    1,a
>    _
>    ___
>    0,9
>    ___
>    ___

As Juncheng points out, it is a bit odd that -n and -g disagree here, 
even in locales where ',' is not a decimal point. For example:

$ printf '1,a\n0,9\n' | sort -gk1 -t, --debug
sort: text ordering performed using ‘en_US.UTF-8’ sorting rules
sort: key 1 is numeric and spans multiple fields
0,9
_
___
1,a
_
___
$ printf '1,a\n0,9\n' | sort -nk1 -t, --debug
sort: text ordering performed using ‘en_US.UTF-8’ sorting rules
sort: key 1 is numeric and spans multiple fields
1,a
_
___
0,9
___
___