Issue specific to v4 action behind proxy when using a token

[damian-sloane-anz]

I am working within a heavily firewalled environment where all traffic is forced to egress via a proxy. I have discovered an issue just recently that appears to be specific to the v4 release when using a GitHub app token.

  steps:
    - name: checkout-xxx
      uses: actions/checkout@v4
      with:
        repository: xxx/repo
        token: ${{ inputs.token }}
        path: ./xxx

When running I get this error:

Determining the default branch
Retrieving the default branch name
Request was cancelled.
Waiting 10 seconds before trying again
Retrieving the default branch name
Request was cancelled.
Waiting 18 seconds before trying again
Retrieving the default branch name
Error: Request was cancelled.

I'm no stranger to the joys of running behind a proxy, especially when it comes to NodeJS ignoring HTTP_PROXY/HTTPS_PROXY environment variables and this "Request was cancelled" is a fairy typical symptom I've seen when thats the underlying cause.

What strange is that for once this doesn't appear to be the environment/workflow at fault, and its not an issue with the token being invalid- because if I simply change to using actions/checkout@v3 version, everything works fine. Likewise if I run git clone CLI using the token in the same workflow- everythings fine.

I read that v4 apparently introduced a bunch of features like this determining default branch--- is it possible that its using Octokit and not performing proxy setup? (or am I just an idiot that has no idea what they're talking about)