vcontainer: add BBMASK for parse savings and suppress layer warnings

The initial vcontainer distro had no BBMASK at all, making it
effectively poky with fewer DISTRO_FEATURES. Every multiconfig parsed
the entire recipe universe even though container image builds only
need a small subset. With 4+ multiconfigs, the parse overhead is
significant.

Add vcontainer-bbmask.inc as a lighter alternative to vruntime's
aggressive BBMASK. It masks the same categories irrelevant to any
container/VM build (graphics, multimedia, desktop, virtualization
platforms, orchestration tools, meta-python, meta-filesystems,
meta-webserver) but keeps the OCI tooling that vruntime blocks:
umoci, container-registry, image recipes, sloci, oci-image-tools.

Masking entire layers (meta-python, meta-filesystems, meta-webserver)
produces BBFILE_PATTERN warnings because the layers are registered in
bblayers.conf (shared with the main build) but have zero recipes after
masking. BitBake provides BBFILE_PATTERN_IGNORE_EMPTY_<collection>
to suppress this, but checks it on self.data (the base datastore),
not per-multiconfig datastores. Setting it in the distro config has
no effect. Move the suppression to meta-virt-host.conf which is
included by the main build's local.conf and therefore visible to
the base datastore.

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

4 files changed, 147 insertions, 12 deletions

diff --git a/conf/distro/include/meta-virt-host.conf b/conf/distro/include/meta-virt-host.conf
index 36fcc09f..8c898f48 100644
--- a/conf/distro/include/meta-virt-host.conf
+++ b/conf/distro/include/meta-virt-host.conf
@@ -20,3 +20,12 @@ PREFERRED_PROVIDER_virtual/runc ?= "runc"
 #   vruntime-*   : minimal VM rootfs (vdkr/vpdmn blobs)
 #   container-*  : OCI container images (multi-arch)
 BBMULTICONFIG ?= "vruntime-aarch64 vruntime-x86-64 container-aarch64 container-x86-64"
+
+# Suppress warnings for layers fully masked in vruntime/vcontainer multiconfigs.
+# These layers are in bblayers.conf (needed by the main build) but their
+# recipes are irrelevant to container/VM multiconfigs. BitBake checks
+# BBFILE_PATTERN_IGNORE_EMPTY on self.data (the base datastore), not
+# per-multiconfig, so this must be set here rather than in the distro config.
+BBFILE_PATTERN_IGNORE_EMPTY_filesystems-layer = "1"
+BBFILE_PATTERN_IGNORE_EMPTY_meta-python = "1"
+BBFILE_PATTERN_IGNORE_EMPTY_webserver = "1"
diff --git a/conf/distro/include/vcontainer-bbmask.inc b/conf/distro/include/vcontainer-bbmask.inc
new file mode 100644
index 00000000..ac74464f
--- /dev/null
+++ b/conf/distro/include/vcontainer-bbmask.inc
@@ -0,0 +1,122 @@
+# SPDX-FileCopyrightText: Copyright (C) 2025 Bruce Ashfield
+#
+# SPDX-License-Identifier: MIT
+#
+# BBMASK for vcontainer OCI image builder multiconfig builds.
+#
+# Lighter than vruntime's BBMASK: masks recipes irrelevant to container
+# image construction (virtualization platforms, graphics, multimedia,
+# desktop, orchestration) but keeps OCI tooling (umoci, skopeo),
+# container image recipes, and the full container stack available.
+#
+# The vruntime BBMASK cannot be reused directly because it masks umoci,
+# container-registry, recipes-extended/images/, and other recipes needed
+# for OCI image building. BitBake BBMASK is append-only (no removal),
+# so a separate lighter mask is required.
+
+# ---------------------------------------------------------------------------
+# oe-core: same masks as vruntime (graphics, multimedia, sato, rt)
+# These are irrelevant to container image building.
+# ---------------------------------------------------------------------------
+BBMASK += "/meta/recipes-graphics/(?!wayland|libsdl2|virglrenderer|libepoxy|drm|mesa|spir|xorg-lib|xorg-proto|xorg-app|xorg-util)"
+BBMASK += "/meta/recipes-multimedia/(?!alsa|libpng)"
+BBMASK += "/meta/recipes-sato/"
+BBMASK += "/meta/recipes-rt/"
+BBMASK += "meta-yocto-bsp/recipes-graphics/xorg-xserver/xserver-xf86-config"
+BBMASK += "meta-erlang/recipes-graphics/mesa/libglu"
+
+# ---------------------------------------------------------------------------
+# meta-virtualization: virtualization platforms (not containers)
+# Same as vruntime — Xen, libvirt, etc. are irrelevant for OCI images.
+# ---------------------------------------------------------------------------
+BBMASK += "meta-virtualization/recipes-extended/xen/"
+BBMASK += "meta-virtualization/recipes-extended/xvisor/"
+BBMASK += "meta-virtualization/recipes-extended/kvmtool/"
+BBMASK += "meta-virtualization/recipes-extended/libvirt/"
+BBMASK += "meta-virtualization/recipes-extended/libvmi/"
+BBMASK += "meta-virtualization/recipes-extended/virt-manager/"
+BBMASK += "meta-virtualization/recipes-extended/virt-viewer/"
+BBMASK += "meta-virtualization/recipes-extended/virt-what/"
+BBMASK += "meta-virtualization/recipes-extended/vhost-device/"
+BBMASK += "meta-virtualization/recipes-extended/dev86/"
+BBMASK += "meta-virtualization/recipes-extended/seabios/"
+BBMASK += "meta-virtualization/recipes-extended/vgabios/"
+BBMASK += "meta-virtualization/recipes-extended/upx/"
+BBMASK += "meta-virtualization/recipes-extended/uxen/"
+BBMASK += "meta-virtualization/recipes-extended/ipxe/"
+BBMASK += "meta-virtualization/recipes-extended/diod/"
+BBMASK += "meta-virtualization/recipes-extended/virtiofsd/"
+
+# ---------------------------------------------------------------------------
+# meta-virtualization: infrastructure / monitoring
+# ---------------------------------------------------------------------------
+BBMASK += "meta-virtualization/recipes-extended/ceph/"
+BBMASK += "meta-virtualization/recipes-extended/cloud-init/"
+BBMASK += "meta-virtualization/recipes-extended/cockpit-machines/"
+BBMASK += "meta-virtualization/recipes-extended/nagios/"
+BBMASK += "meta-virtualization/recipes-extended/oath/"
+BBMASK += "meta-virtualization/recipes-extended/irqbalance/"
+
+# ---------------------------------------------------------------------------
+# meta-virtualization: container orchestration / tools not needed for images
+# ---------------------------------------------------------------------------
+BBMASK += "meta-virtualization/recipes-containers/kubernetes/"
+BBMASK += "meta-virtualization/recipes-containers/k3s/"
+BBMASK += "meta-virtualization/recipes-containers/cri-o/"
+BBMASK += "meta-virtualization/recipes-containers/cri-tools/"
+BBMASK += "meta-virtualization/recipes-containers/docker-compose/"
+BBMASK += "meta-virtualization/recipes-containers/podman-compose/"
+BBMASK += "meta-virtualization/recipes-containers/podman-tui/"
+BBMASK += "meta-virtualization/recipes-containers/nerdctl/"
+BBMASK += "meta-virtualization/recipes-containers/buildah/"
+BBMASK += "meta-virtualization/recipes-containers/singularity/"
+BBMASK += "meta-virtualization/recipes-containers/lxc/"
+BBMASK += "meta-virtualization/recipes-containers/lxcfs/"
+BBMASK += "meta-virtualization/recipes-containers/criu/"
+
+# ---------------------------------------------------------------------------
+# meta-virtualization: other categories not needed for container images
+# ---------------------------------------------------------------------------
+BBMASK += "meta-virtualization/recipes-demo/"
+BBMASK += "meta-virtualization/recipes-graphics/"
+BBMASK += "meta-virtualization/recipes-core/kata-containers/"
+BBMASK += "meta-virtualization/recipes-core/runx/"
+BBMASK += "meta-virtualization/recipes-networking/openvswitch/"
+BBMASK += "meta-virtualization/recipes-networking/netns/"
+BBMASK += "meta-virtualization/recipes-networking/passt/"
+
+# ---------------------------------------------------------------------------
+# meta-oe / meta-networking: mask heavyweight categories
+# ---------------------------------------------------------------------------
+BBMASK += "meta-oe/recipes-(?!devtools|extended|support)"
+BBMASK += "meta-networking/recipes-(?!filter|support)"
+BBMASK += "meta-openstack/recipes-dbs/postgresql/"
+BBMASK += "meta-oe/dynamic-layers/networking-layer/recipes-core/"
+BBMASK += "meta-openstack/recipes-extended/libvirt/"
+
+# ---------------------------------------------------------------------------
+# Entire layers with 0 recipes in the container image dependency graph.
+# Clear BBFILE_COLLECTIONS entries for fully-masked layers so BitBake
+# does not warn about zero files matching BBFILE_PATTERN.
+# ---------------------------------------------------------------------------
+BBMASK += "meta-filesystems/"
+BBMASK += "meta-python/"
+BBMASK += "meta-webserver/"
+# Warning suppression for these fully-masked layers is in meta-virt-host.conf
+# (BBFILE_PATTERN_IGNORE_EMPTY) because BitBake checks the base datastore,
+# not per-multiconfig datastores.
+
+# ---------------------------------------------------------------------------
+# NOT MASKED (differs from vruntime):
+#   recipes-extended/images/          - container image recipes
+#   recipes-containers/umoci/         - OCI image manipulation
+#   recipes-containers/container-registry/ - registry push
+#   recipes-containers/oci-image-tools/    - OCI tooling
+#   recipes-containers/oci-image-spec/     - OCI spec
+#   recipes-containers/sloci-image/        - simple OCI image builder
+#   recipes-containers/oci-base-images/    - external base images
+#   recipes-extended/container-bundles/    - container bundling
+#   recipes-extended/container-cross-deploy/ - cross-install
+#   recipes-extended/fuse-overlayfs/       - overlay support
+#   recipes-extended/rootlesskit/          - rootless containers
+# ---------------------------------------------------------------------------
diff --git a/conf/distro/include/vruntime-bbmask-meta-oe.inc b/conf/distro/include/vruntime-bbmask-meta-oe.inc
index a2e2e77f..bb3b88a6 100644
--- a/conf/distro/include/vruntime-bbmask-meta-oe.inc
+++ b/conf/distro/include/vruntime-bbmask-meta-oe.inc
@@ -30,19 +30,18 @@ BBMASK += "meta-oe/recipes-(?!devtools|extended|support)"
 BBMASK += "meta-networking/recipes-(?!filter|support)"
 
 # ---------------------------------------------------------------------------
-# meta-filesystems: entire layer (0 recipes in dependency graph)
+# Entire layers with 0 recipes in the dependency graph.
+# Clear BBFILE_COLLECTIONS entries for fully-masked layers so BitBake
+# does not warn about zero files matching BBFILE_PATTERN.
+# The layers remain in bblayers.conf (shared with main build) but
+# contribute no recipes to vruntime/vcontainer multiconfigs.
 # ---------------------------------------------------------------------------
 BBMASK += "meta-filesystems/"
-
-# ---------------------------------------------------------------------------
-# meta-python: entire layer (0 recipes in dependency graph)
-# ---------------------------------------------------------------------------
 BBMASK += "meta-python/"
-
-# ---------------------------------------------------------------------------
-# meta-webserver: entire layer (0 recipes in dependency graph)
-# ---------------------------------------------------------------------------
 BBMASK += "meta-webserver/"
+# Warning suppression for these fully-masked layers is in meta-virt-host.conf
+# (BBFILE_PATTERN_IGNORE_EMPTY) because BitBake checks the base datastore,
+# not per-multiconfig datastores.
 
 # ---------------------------------------------------------------------------
 # Orphaned bbappends in other layers (base recipes masked above)
diff --git a/conf/distro/vcontainer.conf b/conf/distro/vcontainer.conf
index 3b81a46c..97d4bc96 100644
--- a/conf/distro/vcontainer.conf
+++ b/conf/distro/vcontainer.conf
@@ -4,15 +4,20 @@
 #
 # VContainer - OCI container image builder distro
 #
-# Shares the same stripped DISTRO_FEATURES as vruntime but without BBMASK,
-# so OCI tooling (umoci, jq, skopeo) and the full package set are available.
+# Shares the same stripped DISTRO_FEATURES as vruntime (via vruntime-base.inc)
+# but uses a lighter BBMASK that keeps OCI tooling available while still
+# masking irrelevant recipes (graphics, multimedia, virtualization platforms,
+# orchestration tools).
 #
 # Used by container-aarch64 / container-x86-64 multiconfigs to build
 # single-arch OCI images that are then combined into multi-arch indexes.
 
 require conf/distro/include/vruntime-base.inc
 
-# No BBMASK -- OCI image building needs umoci, jq, and full package set.
+# Lighter BBMASK than vruntime: masks graphics, multimedia, desktop,
+# virtualization platforms, and orchestration tools, but keeps OCI tooling
+# (umoci, container-registry, image recipes) that vruntime blocks.
+require conf/distro/include/vcontainer-bbmask.inc
 
 DISTRO = "vcontainer"
 DISTRO_NAME = "VContainer OCI Builder"