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From:   Junio C Hamano <gitster@pobox.com>
To:     Carlo Arenas <carenas@gmail.com>
Cc:     =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason <avarab@gmail.com>,
        git@vger.kernel.org, Eric Sunshine <sunshine@sunshineco.com>,
        Phillip Wood <phillip.wood@talktalk.net>
Subject: Re: [PATCH v2] CI: select CC based on CC_PACKAGE (again)
References: <patch-1.1-d89ad4d5b7c-20220421T130310Z-avarab@gmail.com>
        <patch-v2-1.1-92acf9420a9-20220421T174733Z-avarab@gmail.com>
        <CAPUEspggNfra_C8PBcVqjZrxxnswg27WFLg2kT6JOCMB8f0FGg@mail.gmail.com>
Date:   Thu, 21 Apr 2022 12:11:58 -0700
In-Reply-To: <CAPUEspggNfra_C8PBcVqjZrxxnswg27WFLg2kT6JOCMB8f0FGg@mail.gmail.com>
        (Carlo Arenas's message of "Thu, 21 Apr 2022 12:05:20 -0700")
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Carlo Arenas <carenas@gmail.com> writes:

>> -       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.