Re: [PATCH v2] CI: select CC based on CC_PACKAGE (again)

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 21, 2022, 19:11 UTC
Message-ID: <xmqqv8v2gsjl.fsf@gitster.g>
In-Reply-To: <CAPUEspggNfra_C8PBcVqjZrxxnswg27WFLg2kT6JOCMB8f0FGg@mail.gmail.com>

Carlo Arenas <carenas@gmail.com> writes:

Show 6 quoted lines

>> -       CC="${CC:-gcc}"
>> +       CC="${CC_PACKAGE:-${CC:-gcc}}"
>
> minor nitpick, but most likely still relevant considering your other
> "bashism" fixes.
> the POSIX syntax doesn't use ":" (documented in CodingGuidelines)

You are reading the guideline wrong, I am afraid.

This is not a substring substitution, ${foo:0:3} picking three characters from the beginning of foo.

It is "If CC_PACKAGE is UNSET OR SET TO EMPTY, then use the fallback value that is ${CC:-gcc}", which is a bog standard bourne shell that predates POSIX. The colon before "-" is what adds "OR SET TO EMPTY" part; without the colon, i.e. "${CC_PACKAGE-${CC-gcc}}", then you get the same without "OR SET TO EMPTY" part.

And we do use that form.