[meta-virtualization] [PATCH] xen: avoid parse time errors for non-xen-archs

[Christopher Larson]

XEN_TARGET_ARCH, when expanded, would emit a bb.error(). Referencing
XEN_TARGET_ARCH in PACKAGECONFIG resulted in its expansion at the up front
parse time, rather than at compile time, so non-xen-supported-archs like
powerpc would see parse time errors, resulting in non-zero bitbake exit codes.

Naturally this isn't ideal, so instead have the mapping function return
'INVALID' in the unsupported case, and in anonymous python, raise SkipPackage
if the mapped architecture is invalid, so it's seen as unbuildable in that
case.

Signed-off-by: Christopher Larson <kergoth at gmail.com>
---
 recipes-extended/xen/xen-arch.inc | 2 +-
 recipes-extended/xen/xen.inc      | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/recipes-extended/xen/xen-arch.inc b/recipes-extended/xen/xen-arch.inc
index bcf9f54..fb0093e 100644
--- a/recipes-extended/xen/xen-arch.inc
+++ b/recipes-extended/xen/xen-arch.inc
@@ -14,5 +14,5 @@ def map_xen_arch(a, d):
     elif re.match("aarch64.*", a):   return "arm64"
     elif a in valid_archs:           return a
     else:
-        bb.error("cannot map '%s' to a xen architecture" % a)
+        return "INVALID"
 
diff --git a/recipes-extended/xen/xen.inc b/recipes-extended/xen/xen.inc
index 0e4136a..432bf4d 100644
--- a/recipes-extended/xen/xen.inc
+++ b/recipes-extended/xen/xen.inc
@@ -663,6 +663,11 @@ export STAGING_LIBDIR
 export XEN_TARGET_ARCH = "${@map_xen_arch(d.getVar('TARGET_ARCH', True), d)}"
 export XEN_COMPILE_ARCH = "${@map_xen_arch(d.getVar('BUILD_ARCH', True), d)}"
 
+python () {
+    if d.getVar('XEN_TARGET_ARCH', True) == 'INVALID':
+        raise bb.parse.SkipPackage('Cannot map `%s` to a xen architecture' % d.getVar('TARGET_ARCH', True))
+}
+
 # hardcoded as Linux, as the only compatible hosts are Linux.
 export XEN_OS = "Linux"
 
-- 
2.2.1