vcontainer: enable incremental builds by default

Previously, vcontainer recipes had [nostamp] flags that forced all
tasks to rebuild on every bitbake invocation, even when nothing changed.
This was added as a workaround for dependency tracking issues but caused
slow rebuild times.

Changes:
- Make [nostamp] conditional on VCONTAINER_FORCE_BUILD variable
- Default to normal stamp-based caching for faster incremental builds
- file-checksums on do_rootfs still tracks init script changes
- Add VCONTAINER_FORCE_BUILD status to the tarball build banner

To enable the old always-rebuild behavior (for debugging dependency
issues), set in local.conf:
  VCONTAINER_FORCE_BUILD = "1"

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

1 files changed, 9 insertions, 0 deletions

diff --git a/recipes-containers/vcontainer/vcontainer-tarball.bb b/recipes-containers/vcontainer/vcontainer-tarball.bb
index 180f3c19..a4e9a9a5 100644
--- a/recipes-containers/vcontainer/vcontainer-tarball.bb
+++ b/recipes-containers/vcontainer/vcontainer-tarball.bb
@@ -144,6 +144,15 @@ python () {
         bb.plain("  To build only one architecture, set in local.conf:")
         bb.plain("    VCONTAINER_ARCHITECTURES = \"x86_64\"")
         bb.plain("    VCONTAINER_ARCHITECTURES = \"aarch64\"")
+        bb.plain("")
+        force = d.getVar('VCONTAINER_FORCE_BUILD') or ''
+        if force == '1':
+            bb.plain("  VCONTAINER_FORCE_BUILD = \"1\" (enabled)")
+            bb.plain("    All vcontainer tasks will rebuild unconditionally.")
+        else:
+            bb.plain("  Incremental builds enabled (default).")
+            bb.plain("    To force full rebuild, set in local.conf:")
+            bb.plain("      VCONTAINER_FORCE_BUILD = \"1\"")
         bb.plain("=" * 70)
         bb.plain("")
 }