[PATCH] multilib.bbclass: Filter ROOTFS_RO_UNNEEDED to fix uninstallation

[mac@mcrowe.com]

From: Mike Crowe <mac@mcrowe.com>

When building an entire multilib image (e.g. lib32-core-image-minimal)
we need to ensure that the unneeded packages in ROOTFS_RO_UNNEEDED get
the multilib prefix applied before they are compared against the list of
installed packages inside Rootfs._uninstall_unneeded() to decide whether
they need to be installed.

Before this change with local.conf containing:

 MACHINE = qemuarm64
 require conf/multilib.conf
 MULTILIBS = "multilib:lib32"
 DEFAULTTUNE:virtclass-multilib-lib32 = "armv7at-neon"
 IMAGE_FEATURES = "read-only-rootfs"

running:
 bitbake lib32-core-image-minimal
 tar tavf tmp/deploy/images/qemuarm64/lib32-core-image-minimal-qemuarm64.rootfs.tar.zst|grep postinst

shows three files:
 -rwxr-xr-x 0/0              25 2018-03-09 12:34 ./etc/init.d/run-postinsts
 lrwxrwxrwx 0/0               0 2018-03-09 12:34 ./etc/rcS.d/S99run-postinsts -> ../init.d/run-postinsts
 -rwxr-xr-x 0/0            2153 2018-03-09 12:34 ./usr/sbin/run-postinsts

whereas with this change there are no matching files.

Signed-off-by: Mike Crowe <mac@mcrowe.com>
---
 meta/classes/multilib.bbclass | 1 +
 1 file changed, 1 insertion(+)

Rootfs._uninstall_unneeded can also try to uninstall run-postinsts
without using the multilib prefix right at the top. I could fix that
with d.expand("${MLPREFIX}run-postinsts") it feels wrong to sully the
generic code with something multilib specific. Advice welcome.

diff --git a/meta/classes/multilib.bbclass b/meta/classes/multilib.bbclass
index 677dbc854a..15056dac4d 100644
--- a/meta/classes/multilib.bbclass
+++ b/meta/classes/multilib.bbclass
@@ -116,6 +116,7 @@ python __anonymous () {
         clsextend = oe.classextend.ClassExtender(variant, prefixes, d)
         clsextend.set_filter("PACKAGE_INSTALL", deps=False)
         clsextend.set_filter("LINGUAS_INSTALL", deps=False)
+        clsextend.set_filter("ROOTFS_RO_UNNEEDED", deps=False)
         clsextend.set_filter("RDEPENDS", deps=True)
         pinstall = d.getVar("LINGUAS_INSTALL") + " " + d.getVar("PACKAGE_INSTALL")
         d.setVar("PACKAGE_INSTALL", pinstall)
-- 
2.39.5