[Mantic/Noble/Unstable][SRU][PATCH] UBUNTU: [Packaging] Fix kernel module compression failures

[Juerg Haefliger]

BugLink: https://bugs.launchpad.net/bugs/2044512

The kernel module compression step is run for every binary package,
not just the modules packages. This results in a build failure when
run in a console for packages that don't contain any .ko files:

\# Compress kernel modules
find debian/linux-unstable-tools-6.6.0-12 -name '*.ko' -print0 | xargs -0 -n1 -P 8 zstd -19 --quiet --rm
stdout is a console, aborting
make: *** [debian/rules.d/2-binary-arch.mk:769: binary-perarch] Error 123

Basically, if find returns nothing, zstd tries to read from stdin:
$ echo | xargs zstd
stdout is a console, aborting
$ echo $?
123

To fix that, tell xargs not to run the command if stdin is empty:
$ echo | xargs -r zstd
$ echo $?
0

Signed-off-by: Juerg Haefliger <juerg.haefliger at canonical.com>
---
 debian/rules.d/2-binary-arch.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/debian/rules.d/2-binary-arch.mk b/debian/rules.d/2-binary-arch.mk
index 79e3e857e2c8..f1950bbdcb92 100644
--- a/debian/rules.d/2-binary-arch.mk
+++ b/debian/rules.d/2-binary-arch.mk
@@ -542,7 +542,7 @@ define dh_all
 	dh_installdocs -p$(1)
 	dh_compress -p$(1)
 	# Compress kernel modules
-	find debian/$(1) -name '*.ko' -print0 | xargs -0 -n1 -P $(CONCURRENCY_LEVEL) zstd -19 --quiet --rm
+	find debian/$(1) -name '*.ko' -print0 | xargs -0 -n1 -P $(CONCURRENCY_LEVEL) -r zstd -19 --quiet --rm
 	dh_fixperms -p$(1) -X/boot/
 	dh_shlibdeps -p$(1) $(shlibdeps_opts)
 	dh_installdeb -p$(1)
-- 
2.40.1