Re: [gentoo-portage-dev] Fix all misc. bash errors.

[Zac Medico]

On 02/05/2018 06:33 PM, R0b0t1 wrote:
> On Sun, Feb 4, 2018 at 10:45 PM, Zac Medico <zmedico@g.o> wrote:
>> On 02/04/2018 07:22 PM, R0b0t1 wrote:
>>> diff --git a/bin/isolated-functions.sh b/bin/isolated-functions.sh
>>> index b28e44f18..377b32d90 100644
>>> --- a/bin/isolated-functions.sh
>>> +++ b/bin/isolated-functions.sh
>>> @@ -82,7 +82,7 @@ __dump_trace() {
>>>          lineno=${BASH_LINENO[${n} - 1]}
>>>          # Display function arguments
>>>          args=
>>> -        if [[ -n "${BASH_ARGV[@]}" ]]; then
>>> +        if [[ -n "${BASH_ARGV[*]}" ]]; then
>>
>> I feel like the shellcheck authors might be willing to accept [[ -n
>> ${BASH_ARGV[@]} ]] or [[ ${BASH_ARGV[@]} ]] as correct, since the
>> "Problematic code" that they cite involves an incorrect comparison:
>>
>> https://github.com/koalaman/shellcheck/wiki/SC2199#problematic-code
>>
>
> This example might be more illustrative:
>
> argc () {
>     echo $#
> }
>
> argc "${BASH_ARGV[*]}"
> argc "${BASH_ARGV[@]}"
>
>
> Output (./test.sh a b):
>
> 1
> 2
>
>
> Which changes the semantics of the tests in which it is present. It is
> hard to know what [[ is doing; if the same is attempted with [ it
> would be an error for the same reason that globbing produces errors.
> See:
>
> [  "${BASH_ARGV[*]}"  ]
> [  "${BASH_ARGV[@]}"  ] # Fails; [: b: unary operator expected
> [[ "${BASH_ARGV[*]}" ]]
> [[ "${BASH_ARGV[@]}" ]]
>
>
> It is possible [[ ignores the extra elements. I can't think of a
> reason where this would make the results of the test different. At the
> same time, it might give people the wrong impression of the operation
> of [.
>
> In the sense that [ and [[ represent test(1), anything but the "[*]"
> expansion is incorrect, as the error message indicates. That [[ treats
> its arguments specially because it is a feature of the syntax just
> makes the situation more confusing.

I've turned this into an optimization by testing the array length
instead of expanding the elements:

https://gitweb.gentoo.org/proj/portage.git/commit/?id=2306b8f4a2d781db87ee61707f6dea1c5f717936
-- 
Thanks,
Zac