Access to main branch cache form feature branch

[rrabenda]

Description

Hello,

I'm trying to speed up builds on feature branches, by pulling cache form main but I'm not able to achieve that. Following Github documentation it should be possible:

Access restrictions provide cache isolation and security by creating a logical boundary between different branches or tags. Workflow runs can restore caches created in either the current branch or the default branch (usually main).

I used something like this in my workflows:

feature branch:

- name: Build and export
  uses: docker/build-push-action@v5
  with:
    context: .
    cache-from:  |
      type=gha
      type=gha,scope=main
    cache-to: type=gha,mode=min,scope=main
    build-args: |
      VERSION=""
    load: true
    tags: app:latest
    outputs: type=docker,dest=build.tar

main branch:

- name: Build and export
  uses: docker/build-push-action@v5
  with:
    context: .
    cache-from: type=gha,scope=main
    cache-to: type=gha,mode=min,scope=main
    build-args: |
      VERSION=""
    load: true
    tags: app:latest
    outputs: type=docker,dest=build.tar

I was doing some variation of that solution, as setting only the same scope for both branches or removing scope form main branch, but nothing worked for me.

Do you have any suggestion? Thanks in advance.