pack rebase require --force. Why?

[sdsani]

We have been using paketo buildpacks in our company from a while to build the container images. Now we are trying to use pack rebase option. Below is the use case that I want take input about.

I built an image for a spring boot application using a builder (paketobuildpacks/builder-jammy-base:x.y.z) and run image (paketobuildpacks/run-jammy-base:0.1.207).

Now I am trying to rebase this image to update the base layer (OS). First I tried using latest run image which is paketobuildpacks/run-jammy-base:0.1.216 and I received following error.

ERROR: rebase app image: new base image 'paketobuildpacks/run-jammy-base:0.1.216' not found in existing run image metadata: {"topLayer":"sha256:3ec203ed1bb694a116205f9e6d9c4dae4b7b42e3b5cef81cd4c3aec504f405e4","reference":"6ebac55296453467586f2ca015779868668398effd1c53d2d2a7372956a86fed","image":"paketobuildpacks/run-jammy-base:0.1.198"}; please provide -force to override

As we can see that error is suggesting use of --force flag. First of all, I was not expecting this. I thought may something has changed between 207 and 216 that breaks the compatibility (which should not be the case since I am just updating patch version), so I tried using rebase with 0.2.208 and I got the same error.

Only time that it works is if I use rebase with paketobuildpacks/run-jammy-base:0.1.207. I wonder why would someone use the same image for rebasing?

I submitted a request on paketo buildpacks channel on slack and they said that it make no sense and suggested post it here since it might be something in pack cli. I have no problem using --force flag, however, my point is that if I have to use it all the time, then why an extra flag?

Please advise what I am missing here.

[pacostas]

The builder.toml of the jammy builder has a different format based on what he noble builder has. Specifically the jammy builder uses the stacks and noble builder uses base images (as stacks are deprecated). If you have some time for experimentation, can you please create a builder with the noble format https://github.com/paketo-buildpacks/ubuntu-noble-builder/blob/main/builders/builder/builder.toml and on the run images section https://github.com/paketo-buildpacks/ubuntu-noble-builder/blob/7748bb71afca25554123516abf6f3bd773c51157/builders/builder/builder.toml#L69-L72 add the the run image where you use on the rebase flag?

something like that

[run]

  [[run.images]]
    image = "docker.io/paketobuildpacks/ubuntu-noble-run:latest"
  [[run.images]]
    image = "docker.io/paketobuildpacks/ubuntu-noble-run-tiny:latest"

then on the rebase use the paketobuildpacks/ubuntu-noble-run-tiny and check if the error will happen

[sdsani]

Thanks for the response here. Let me start with a recap here to make sure that I am not missing something here. Keep in mind that following is a more recent example so run image version could be slightly different than the one provided in the original post.

Original image was built using following:
Builder: paketobuildpacks/builder-jammy-base:0.4.557
Run: run-jammy-base-0.1.217

Now I am trying to rebase using following command
pack rebase repo.primetherapeutics.com:17443/XXX/existing-image-name-with-tag ^
--run-image paketobuildpacks/run-jammy-base:0.1.220

In other words, updating from run-jammy-base:0.1.217 to run-jammy-base:0.1.220.

In this process, I don't want to use a builder which present a different stack (example noble). I did check the supported parameters for the pack rebase, and I don't see a way to explicitly provide a builder using an input params.

Your response above makes me think that it always picks up the most recent builder image (at this point noble is the most current builder image) by default? Please advise.