Re: [PATCH 2/2] Windows: stop supplying BLK_SHA1=YesPlease by default

On Wed, Dec 27 2017, Jonathan Nieder jotted:

+git-for-windows
Ævar Arnfjörð Bjarmason wrote:

quoted

Using BLK_SHA1 in lieu of the OpenSSL routines was done in [1], but
since DC_SHA1 is now the default for git in general it makes sense for
Windows to use that too, this looks like something that was missed
back in [2].

As noted in [3] OpenSSL has a performance benefit compared to BLK_SHA1
on MinGW, so perhaps that and the Windows default should be changed
around again, but that's a topic for another series, it seems clear
that this specific flag is nobody's explicit intention.

I have some memory of performance issues on Windows when DC_SHA1 was
introduced leading to interest in a mixed configuration with DC_SHA1
only being used where it is security sensitive (e.g. for object naming
but not for packfile trailers).

Did anything come of that?

This was Johannes Schindelin (CC'd) on-list when the sha1dc discussion
first came up earlier this year. I.e. it's slower, so we could use
openssl on trusted data and sha1dc on untrusted data, but nothing came
of that.

In any event removing this BLK_SHA1 setting looks like a good change
to me, but I'd rather that Windows folks weigh in.

Yup, will CC them + Johannes for v2.

Thanks,
Jonathan

[...]

quoted

--- a/config.mak.uname
+++ b/config.mak.uname

@@ -361,7 +361,6 @@ ifeq ($(uname_S),Windows)
 	NO_REGEX = YesPlease
 	NO_GETTEXT = YesPlease
 	NO_PYTHON = YesPlease
-	BLK_SHA1 = YesPlease
 	ETAGS_TARGET = ETAGS
 	NO_INET_PTON = YesPlease
 	NO_INET_NTOP = YesPlease