Re: [gentoo-dev] Re: [PATCH] eclass/kernel-2.eclass: Remove use of tr in global scope

[Ulrich Mueller]

>>>>> On Thu, 31 Aug 2017, Michał Górny wrote:

>> > @@ -1425,9 +1426,10 @@ detect_arch() {
>> >         COMPAT_URI="${!COMPAT_URI}"
>> >
>> >         [[ -n ${COMPAT_URI} ]] && \
>> > -           ARCH_URI="${ARCH_URI} $(echo ${LOOP_ARCH} | tr '[:upper:]' '[:lower:]')? ( ${COMPAT_URI} )"
>> > +           ARCH_URI="${ARCH_URI} ${LOOP_ARCH,,}? ( ${COMPAT_URI} )"
>> >
>> > -       if [[ ${LOOP_ARCH} == "$(echo $(tc-arch-kernel) | tr '[:lower:]' '[:upper:]')" ]];  then
>> > +       TC_ARCH_KERNEL=$(tc-arch-kernel);
>> > +       if [[ ${LOOP_ARCH} == ${TC_ARCH_KERNEL^^} ]];   then
>> >
>> >
>>
>> Unfortunately, the ${VAR,,} and ${VAR^^} forms were added in bash
>> 4.0 [1], which means they are not available in EAPIs before 6,
>> which only allow constructs from bash 3.2 [2].
>>
>> [1]: https://tiswww.case.edu/php/chet/bash/NEWS
>> [2]: https://projects.gentoo.org/pms/6/pms.html#x1-640006

> That's what I wanted to say. However, considering it's broken
> anyway, I guess this is kind of improvement (since it technically
> breaks old ebuilds only).

Many kernel ebuilds are still at EAPI 5, though.

> As a cheap alternative, you could just do a big 'case' with
> hardcoded mappings. Or given that ALL_ARCH is already defined, you
> can define ALL_ARCH_LC (lowercase) and map from one to the other.

There is also "shopt -s nocasematch" which is available since
bash 3.1.

Ulrich