[OE-core] [PATCH 7/9] kernel-yocto: test for empty artifacts

[Bruce Ashfield]

With the updated kernel tools, we generate a list of sccs, patches,
configs and BSP definitions as part of the meta data generation.

It is valid if there aren't any of these artifacts found (i.e. you
are just building a branch and a default config), but invoking the
tools with no inputs isn't a good idea.

To avoid this issue, we generate a string based on the artifacts
and skip calling the tools if there's nothing to do.

Signed-off-by: Bruce Ashfield <bruce.ashfield at windriver.com>
---
 meta/classes/kernel-yocto.bbclass | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/meta/classes/kernel-yocto.bbclass b/meta/classes/kernel-yocto.bbclass
index 8650e55de727..9b8bab63ca09 100644
--- a/meta/classes/kernel-yocto.bbclass
+++ b/meta/classes/kernel-yocto.bbclass
@@ -139,10 +139,16 @@ do_kernel_metadata() {
 	meta_dir=$(kgit --meta)
 
 	# run1: pull all the configuration fragments, no matter where they come from
-	scc --force -o ${S}/${meta_dir}:cfg,meta ${includes} ${bsp_definition} ${sccs} ${patches} ${KERNEL_FEATURES}
+	elements="`echo -n ${bsp_definition} ${sccs} ${patches} ${KERNEL_FEATURES}`"
+	if [ -n "${elements}" ]; then
+		scc --force -o ${S}/${meta_dir}:cfg,meta ${includes} ${bsp_definition} ${sccs} ${patches} ${KERNEL_FEATURES}
+	fi
 
 	# run2: only generate patches for elements that have been passed on the SRC_URI
-	scc --force -o ${S}/${meta_dir}:patch --cmds patch ${includes} ${sccs} ${patches} ${KERNEL_FEATURES}
+	elements="`echo -n ${sccs} ${patches} ${KERNEL_FEATURES}`"
+	if [ -n "${elements}" ]; then
+		scc --force -o ${S}/${meta_dir}:patch --cmds patch ${includes} ${sccs} ${patches} ${KERNEL_FEATURES}
+	fi
 }
 
 do_patch() {
-- 
2.5.0