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From:   Junio C Hamano <gitster@pobox.com>
To:     =?utf-8?Q?Jo=C3=A3o?= Victor Bonfim 
        <JoaoVictorBonfim@protonmail.com>
Cc:     Martin Fick <mfick@codeaurora.org>,
        "brian m. carlson" <sandals@crustytoothpaste.net>,
        git@vger.kernel.org
Subject: Re: Fw: Curiosity
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Date:   Fri, 17 Dec 2021 16:24:33 -0800
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        (=?utf-8?Q?=22Jo=C3=A3o?= Victor Bonfim"'s message of "Sat, 18 Dec 2021
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Jo=C3=A3o Victor Bonfim  <JoaoVictorBonfim@protonmail.com> writes:

>> I suspect that for most algorithms and their implementations, this wou=
ld
>>
>> not result in repeatable "recompressed" results. Thus the checked-out
>>
>> files might be different every time you checked them out. :(
>
> How or why?
>
> Sincere question.

Two immediate things that come to my mind are lossy compression
algorithms (jpeg pictures?) and compressors that do not necessarily
produce bit-for-bit identical results (e.g. gzip by default embeds
timestamp unless explicitly told not to from a command line option).