app-container-multilayer: drop redundant IMAGE_INSTALL

The canonical multi-layer demo recipe listed every package in two
places — once in OCI_LAYERS and again in IMAGE_INSTALL — and carried
a four-line comment block explaining why the duplication was needed
to trigger do_rootfs's recrdeptask. The matching bbclass change folds
OCI_LAYERS packages: layers into IMAGE_INSTALL automatically, so the
duplication is no longer needed and the explanatory comment for the
old workaround is no longer accurate.

Drop the IMAGE_INSTALL line and the obsolete comment. Replace them
with a short note in-line with OCI_LAYERS that describes the new
behaviour and tells readers when they would still need to add to
IMAGE_INSTALL themselves (e.g. for packages used only by a rootfs
postprocess fixup that don't land in any final layer).

Functional verification on qemux86-64:

  1. Snapshot the existing build (with explicit IMAGE_INSTALL):
       cp -a tmp/deploy/images/qemux86-64/app-container-multilayer-...-oci /tmp/baseline
       ls -1 /tmp/baseline/blobs/sha256/ | sort > /tmp/baseline.txt

  2. Edit recipe (drop IMAGE_INSTALL), cleansstate, rebuild.

  3. Compare blob digest lists.

Result: all three OCI image layer blobs (the actual container content,
~16 MB total) match byte-for-byte between the two builds. Only the
config and manifest blobs differ, which is expected — they embed the
build timestamp via org.opencontainers.image.created and reference the
new config digest. No layer content drift.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/recipes-demo/images/app-container-multilayer.bb b/recipes-demo/images/app-container-multilayer.bb
index 6a3f2042..a32c299c 100644
--- a/recipes-demo/images/app-container-multilayer.bb
+++ b/recipes-demo/images/app-container-multilayer.bb
@@ -14,6 +14,13 @@ OCI_LAYERS = "\
     app:packages:curl \
 "
 
+# Note: no IMAGE_INSTALL needed for the packages listed above.
+# image-oci.bbclass walks OCI_LAYERS at parse time and folds every
+# package named in a ":packages:" layer into IMAGE_INSTALL automatically,
+# so do_rootfs's recrdeptask builds them. A recipe only needs to set
+# IMAGE_INSTALL itself for packages that are NOT named in any layer
+# (e.g. packages consumed only by a rootfs postprocess fixup).
+
 # Use CMD so `docker run image /bin/sh` works as expected
 OCI_IMAGE_CMD = "/bin/sh -c 'echo Hello from multi-layer container && curl --version'"
 
@@ -25,12 +32,6 @@ IMAGE_FEATURES = ""
 IMAGE_LINGUAS = ""
 NO_RECOMMENDATIONS = "1"
 
-# IMAGE_INSTALL triggers package builds via do_rootfs recrdeptask.
-# Even for multi-layer mode, list packages here to ensure they're built.
-# The PM will install them directly to layers from DEPLOY_DIR_IPK.
-# Note: IMAGE_ROOTFS is still created but ignored for packages layers.
-IMAGE_INSTALL = "base-files base-passwd netbase busybox curl"
-
 # Allow build with or without a specific kernel
 IMAGE_CONTAINER_NO_DUMMY = "1"