[PATCH] Makefile: generate 'git' as 'cc [...] -o git+ && mv git+ git'

From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
	"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [PATCH] Makefile: generate 'git' as 'cc [...] -o git+ && mv git+ git'
Date: Sun,  7 Mar 2021 14:20:01 +0100	[thread overview]
Message-ID: <20210307132001.7485-1-avarab@gmail.com> (raw)

Change the compilation of the main 'git' binary to not have the CC
clobber 'git' in-place. This means that e.g. running the test suite
in-place and recompiling won't fail whatever tests happen to be
running for the duration of the binary being regenerated.

This is not a complete solution, in particular I'm not doing this for
any of the git-* binaries, so it's effectively only for
SKIP_DASHED_BUILT_INS=Y.

I think that's fine for a small best-effort solution to this, even
those who rely on dashed binaries for something are likely mostly
using 'git' for whatever scripts they have running out of their
git.git checkout.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index dfb0f1000fa..c5c754a9a12 100644
--- a/Makefile
+++ b/Makefile
@@ -2159,8 +2159,9 @@ git.sp git.s git.o: EXTRA_CPPFLAGS = \
 	'-DGIT_INFO_PATH="$(infodir_relative_SQ)"'
 
 git$X: git.o GIT-LDFLAGS $(BUILTIN_OBJS) $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) \
-		$(filter %.o,$^) $(LIBS)
+	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@+ $(ALL_LDFLAGS) \
+		$(filter %.o,$^) $(LIBS) && \
+	mv $@+ $@
 
 help.sp help.s help.o: command-list.h
 
-- 
2.31.0.rc0.126.g04f22c5b82

