Re: Git v2.13.1 SHA1 very broken

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 6, 2017, 01:20 UTC
Message-ID: <xmqq4lvtap3m.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CACBZZX6vOr+ZjUaAf8i1xdjEFfY_Exj+_Xn2-1u0RcWoLy+X1g@mail.gmail.com>

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

Show 6 quoted lines

> That looks scary, can you please comment out this:
>
>     #define SHA1DC_ALLOW_UNALIGNED_ACCESS
>
> In sha1dc/sha1.c and see if that helps, alternatively comment out the
> ifdefs guarded by "#ifdef _MSC_VER" calls in sha1dc/sha1.c

That is merely a performance (and theoretical correctness) thing, no?

> The functional differences between 2.13.0 and 2.13.1 on that platform
> should be none aside from possibly those changes, unless I've missed
> something.

If it does not hash correctly, the cause is more likely that the endianness detection is going haywire.

    make CFLAGS="-DSHA1DC_FORCE_LITTLEENDIAN -g -O2 -Wall"

or something like that, perhaps?