[PATCH 3/3] sha1collisiondetection: automatically enable when submodule is populated

From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>, "Jeff King" <peff@peff.net>,
	"Michael Kebe" <michael.kebe@gmail.com>,
	"Liam R . Howlett" <Liam.Howlett@Oracle.com>,
	"Adam Dinwoodie" <adam@dinwoodie.org>,
	"Stefan Beller" <sbeller@google.com>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [PATCH 3/3] sha1collisiondetection: automatically enable when submodule is populated
Date: Tue, 27 Jun 2017 12:17:18 +0000	[thread overview]
Message-ID: <20170627121718.12078-4-avarab@gmail.com> (raw)
In-Reply-To: <20170627121718.12078-1-avarab@gmail.com>
In-Reply-To: <CAKKM46tHq13XiW5C8sux3=PZ1VHSu_npG8ExfWwcPD7rkZkyRQ@mail.gmail.com>

From: Junio C Hamano <gitster@pobox.com>

If a user wants to experiment with the version of collision
detecting sha1 from the submodule, the user needed to not just
populate the submodule but also needed to turn the knob.

A Makefile trick is easy enough to do so, so let's do this.  When
somebody with a copy of the submodule populated wants not to use it,
that can be done by overriding it in config.mak or from the command
line.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index f0cac1f246..3baa1eac0b 100644
--- a/Makefile
+++ b/Makefile
@@ -1009,6 +1009,10 @@ EXTLIBS =
 
 GIT_USER_AGENT = git/$(GIT_VERSION)
 
+ifeq ($(wildcard sha1collisiondetection/lib/sha1.h),sha1collisiondetection/lib/sha1.h)
+DC_SHA1_SUBMODULE = auto
+endif
+
 include config.mak.uname
 -include config.mak.autogen
 -include config.mak
-- 
2.13.1.611.g7e3b11ae1

