[PATCH] u-boot-tools: Fix reproducibility issue

["Richard Purdie" <richard.purdie@linuxfoundation.org>]

If you build on a system with git < 2.14 from scratch (e.g. debian9), the
tree will be marked as "dirty" and the version will include "-dirty", leading
to a reproducibility problem. The issue is the inode count for Licnses/README
changing due to do_populate_lic hardlinking a copy of the file. We avoid
this by ensuring the index is updated with a "git diff" before the
u-boot machinery tries to determine the version.

build$ ../git/scripts/setlocalversion ../git
""
build$ ln ../git/
build$ ln ../git/README ../foo
build$ ../git/scripts/setlocalversion ../git
""-dirty

(i.e. creating a hardlink dirties the index)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
 meta/recipes-bsp/u-boot/u-boot-tools.inc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/meta/recipes-bsp/u-boot/u-boot-tools.inc b/meta/recipes-bsp/u-boot/u-boot-tools.inc
index 8ae290acc61..4ed936a70d3 100644
--- a/meta/recipes-bsp/u-boot/u-boot-tools.inc
+++ b/meta/recipes-bsp/u-boot/u-boot-tools.inc
@@ -23,6 +23,21 @@ SED_CONFIG_EFI_armeb = ''
 SED_CONFIG_EFI_aarch64 = ''
 
 do_compile () {
+	# Yes, this is crazy. If you build on a system with git < 2.14 from scratch, the tree will
+	# be marked as "dirty" and the version will include "-dirty", leading to a reproducibility problem.
+	# The issue is the inode count for Licnses/README changing due to do_populate_lic hardlinking a
+	# copy of the file. We avoid this by ensuring the index is updated with a "git diff" before the
+	# u-boot machinery tries to determine the version.
+	#
+	# build$ ../git/scripts/setlocalversion ../git
+	# ""
+	# build$ ln ../git/
+	# build$ ln ../git/README ../foo
+	# build$ ../git/scripts/setlocalversion ../git
+	# ""-dirty
+	# (i.e. creating a hardlink dirties the index)
+	cd ${S}; git diff; cd ${B}
+
 	oe_runmake -C ${S} sandbox_defconfig O=${B}
 
 	# Disable CONFIG_CMD_LICENSE, license.h is not used by tools and
-- 
2.25.1