Update to support 0.10 of the Buildpack API

[jwhitcraft]

Hello,

I recently ran into a problem when trying to use the heroku based buildpacks where one of their buildpacks didn't define a stacks section in the buildpack.toml file. Kpack says that it's not supported,

message: "validating buildpack heroku [email protected]: stack heroku-24 is not supported"

In talking with that team, it seems that kpack neesd to be updated to support 0.10 where stacks are optional/deprecated.

This came out of this discussion here: heroku/buildpacks-procfile#243

For reference here is when the pack cli fixed it: buildpacks/pack#2047

Yaml

apiVersion: kpack.io/v1alpha2
kind: ClusterBuilder
metadata:
  name: heroku-242
spec:
  order:
    - group:
        - id: heroku/nodejs
        - id: heroku/procfile
  serviceAccountRef:
    name: kpack
    namespace: kpack
  stack:
    kind: ClusterStack
    name: heroku-24
  store:
    kind: ClusterStore
    name: heroku-24
  tag: 1231232132.dkr.ecr.us-east-2.amazonaws.com/heroku-24-builder
  additionalLabels:
    io.buildpacks.base.distro.name: "ubuntu"
    io.buildpacks.base.distro.version: "24.04"

---

apiVersion: kpack.io/v1alpha2
kind: ClusterStack
metadata:
  name: heroku-24
spec:
  buildImage:
    image: public.ecr.aws/heroku/builder:24
  id: heroku-24
  runImage:
    image: public.ecr.aws/heroku/heroku:24

---

apiVersion: kpack.io/v1alpha2
kind: ClusterStore
metadata:
  name: heroku-24
spec:
  sources:
    - image: heroku/buildpack-nodejs:3.2.15
    - image: heroku/buildpack-procfile:3.1.2

[chenbh]

This is something we've been meaning to do for a while now and a lot of the work is already in a PR at #1332. But I'm not sure if I (or even @natalieparellano) have the capacity to pick it up again right now.

[natalieparellano]

From what I can tell, the change would need to be made here:

kpack/pkg/cnb/builder_builder.go

Line 198 in 8d8218b

err := bpLayerInfo.supports(buildpackApis, bb.stackId, bb.mixins, relaxedMixinContract(platformApis))

And test updated here (and perhaps in other places):

kpack/pkg/cnb/create_builder_test.go

Line 676 in 8d8218b

when("validating buildpacks", func() {

As @chenbh mentioned, the team has been stretched a bit thin, so it may take some time for someone to get to this. However this does seem to be a relatively "good first issue" if anyone would like to take it on, I am sure a maintainer would be happy to support.