meta-integrity: add sanity check

Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-integrity/README.md

@@ -1,8 +1,24 @@
 This README file contains information on the contents of the
 integrity layer.
 
-Please see the corresponding sections below for details.
 
+The bbappend files for some recipes (e.g. linux-yocto) in this layer need
+to have 'integrity' in DISTRO_FEATURES to have effect.
+To enable them, add in configuration file the following line.
+
+  DISTRO_FEATURES_append = " integrity"
+
+If meta-integrity is included, but integrity is not enabled as a
+distro feature a warning is printed at parse time:
+
+    You have included the meta-integritry layer, but
+    'integrity' has not been enabled in your DISTRO_FEATURES. Some bbappend files
+    and preferred version setting may not take effect.
+
+If you know what you are doing, this warning can be disabled by setting the following
+variable in your configuration:
+
+  SKIP_META_INTEGRITY_SANITY_CHECK = 1
 
 Dependencies
 ============

meta-integrity/classes/sanity-meta-integrity.bbclass

@@ -0,0 +1,10 @@
+addhandler integrity_bbappend_distrocheck
+integrity_bbappend_distrocheck[eventmask] = "bb.event.SanityCheck"
+python integrity_bbappend_distrocheck() {
+    skip_check = e.data.getVar('SKIP_META_INTEGRITY_SANITY_CHECK') == "1"
+    if 'integrity' not in e.data.getVar('DISTRO_FEATURES').split() and not skip_check:
+        bb.warn("You have included the meta-integrity layer, but \
+'integrity' has not been enabled in your DISTRO_FEATURES. Some bbappend files \
+and preferred version setting may not take effect. See the meta-integrity README \
+for details on enabling integrity support.")
+}

meta-integrity/conf/layer.conf

@@ -26,6 +26,10 @@ LAYERDEPENDS_integrity = "core openembedded-layer"
 
 BBLAYERS_LAYERINDEX_NAME_integrity = "meta-integrity"
 
+# Sanity check for meta-integrity layer.
+# Setting SKIP_META_INTEGRITY_SANITY_CHECK to "1" would skip the bbappend files check.
+INHERIT += "sanity-meta-integrity"
+
 BBFILES_DYNAMIC += " \
 networking-layer:${LAYERDIR}/dynamic-layers/meta-networking/recipes-*/*/*.bbappend \
 "