Hello all,

We are on Yocto 'zeus'.

Our u-boot recipe generates a versions.txt file containing the git commit of the U-Boot source tree. It was pointed out that since recipes can patch the source, just the source commit ID isn't quite enough. So we wanted to also include the git commit of the layer housing the recipe. Call this layer "meta-our-layer".

This is the implementation we tried:

def get_layer_path(d, name):
    layer_list = (d.getVar("BBLAYERS") or "").split()
    return [os.path.abspath(l) for l in layer_list if l.endswith(name)][0]

def get_meta_our_layer_commit(d):
    import subprocess
    output = subprocess.check_output(["git", "rev-parse", "HEAD"], universal_newlines=True, cwd=d.getVar("OUR_LAYER_PATH"))
    return output.strip()

OUR_LAYER_PATH := "${@get_layer_path(d, "meta-our-layer")}"

OUR_LAYER_COMMIT = "${@get_meta_our_layer_commit(d)}"
OUR_LAYER_COMMIT[vardepvalue] = "${@get_meta_our_layer_commit(d)}"

do_deploy_append() {
    echo "meta-our-layer:${OUR_LAYER_COMMIT}" >> ${DEPLOYDIR}/versions.txt
}


However there are two problems:

  1.  Making an empty commit to meta-our-layer doesn't cause the recipe to be re-run. What's weird is that when I use 'bitbake u-boot -e', I can see that the value of  OUR_LAYER_COMMIT is indeed changing. And with bitbake-dumpsig I can see that OUR_LAYER_COMMIT is in the task deps for do_deploy.
  2.  If I build 'u-boot', then make an empty commit to meta-our-layer, and then run "bitbake-whatchanged u-boot", I get a "The metadata is not deterministic and this needs to be fixed." error.

Am I misunderstanding the purpose of vardepvalue? I thought it could be used to here to help bitbake 'see' through values that otherwise change unexpectedly.

Thanks,
Chris