From a120bc54458c38636aec3f414af02f449ecaa44f Mon Sep 17 00:00:00 2001
From: Lyndon Brown <jnqnfe@gmail.com>
Date: Tue, 11 Feb 2020 21:00:14 +0000
Subject: [PATCH] firmware: avoid potentially duplicate work

addressing an old fixme, should distro and parent-distro be identical (in
a derivative build) we want to avoid wasting effort downloading and
processing the same content files twice.

since parent and non-parent have separate archive-area lists though we
should perhaps not just assume that they are identical or ignore any
differences; thus here in such a situation we ensure that we handle any
archive areas not already done for parent-distro handling in such a case,
while skipping those already done.

i notice that the fixme actually also refers to avoiding actual
overlapping of the cached files, however the cached files are (currently)
always ignored anyway, so this is of no concern. reusing the cached files
is an entirely separate issue.

Gbp-Dch: Short
Closes: #952909
---
 scripts/build/chroot_firmware            | 20 ++++++++++++++++++--
 scripts/build/installer_debian-installer | 20 ++++++++++++++++++--
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/scripts/build/chroot_firmware b/scripts/build/chroot_firmware
index 4a65d552a..7fdd7605d 100755
--- a/scripts/build/chroot_firmware
+++ b/scripts/build/chroot_firmware
@@ -79,9 +79,25 @@ Firmware_List_From_Contents "${LB_PARENT_MIRROR_CHROOT}" "${LB_PARENT_DISTRIBUTI
 
 if [ "${LB_DERIVATIVE}" = "true" ]
 then
-	# FIXME: account for the fact that PARENT_DISTRIBUTION and DISTRIBUTION might be the same (to not have overlapping cache files for contents).
+	# Avoid downloading things twice if distributions are identical
+	DERIVATIVE_ARCHIVE_AREAS=""
+	if [ "${LB_DISTRIBUTION_CHROOT}" != "${LB_PARENT_DISTRIBUTION_CHROOT}" ]
+	then
+		DERIVATIVE_ARCHIVE_AREAS="${LB_ARCHIVE_AREAS}"
+	else
+		for _ARCHIVE_AREA in ${LB_ARCHIVE_AREAS}
+		do
+			if ! In_list ${_ARCHIVE_AREA} "${LB_PARENT_ARCHIVE_AREAS}"
+			then
+				DERIVATIVE_ARCHIVE_AREAS="${DERIVATIVE_ARCHIVE_AREAS} ${_ARCHIVE_AREA}"
+			fi
+		done
+	fi
 
-	Firmware_List_From_Contents "${LB_MIRROR_CHROOT}" "${LB_DISTRIBUTION_CHROOT}" "${LB_ARCHIVE_AREAS}"
+	if [ ! -z "${DERIVATIVE_ARCHIVE_AREAS}" ]
+	then
+		Firmware_List_From_Contents "${LB_MIRROR_CHROOT}" "${LB_DISTRIBUTION_CHROOT}" "${DERIVATIVE_ARCHIVE_AREAS}"
+	fi
 fi
 
 # Drop section and keep package names only
diff --git a/scripts/build/installer_debian-installer b/scripts/build/installer_debian-installer
index 67573f2e6..64375e85c 100755
--- a/scripts/build/installer_debian-installer
+++ b/scripts/build/installer_debian-installer
@@ -367,9 +367,25 @@ then
 
 		if [ "${LB_DERIVATIVE}" = "true" ]
 		then
-			# FIXME: account for the fact that PARENT_DISTRIBUTION and DISTRIBUTION might be the same (to not have overlapping cache files for contents).
+			# Avoid downloading things twice if distributions are identical
+			DERIVATIVE_ARCHIVE_AREAS=""
+			if [ "${LB_DISTRIBUTION_CHROOT}" != "${LB_PARENT_DISTRIBUTION_CHROOT}" ]
+			then
+				DERIVATIVE_ARCHIVE_AREAS="${LB_ARCHIVE_AREAS}"
+			else
+				for _ARCHIVE_AREA in ${LB_ARCHIVE_AREAS}
+				do
+					if ! In_list ${_ARCHIVE_AREA} "${LB_PARENT_ARCHIVE_AREAS}"
+					then
+						DERIVATIVE_ARCHIVE_AREAS="${DERIVATIVE_ARCHIVE_AREAS} ${DERIVATIVE_ARCHIVE_AREAS}"
+					fi
+				done
+			fi
 
-			Firmware_List_From_Contents "${LB_MIRROR_CHROOT}" "${LB_DISTRIBUTION_CHROOT}" "${LB_ARCHIVE_AREAS}"
+			if [ ! -z "${DERIVATIVE_ARCHIVE_AREAS}" ]
+			then
+				Firmware_List_From_Contents "${LB_MIRROR_CHROOT}" "${LB_DISTRIBUTION_CHROOT}" "${DERIVATIVE_ARCHIVE_AREAS}"
+			fi
 		fi
 
 		# Drop section and keep package names only