Rcodesign returns configuration file error even if no configuration file is supplied

[m-wack]

We are using rcodesign inside a GitLab Pipeline with an alpine container. For the longest time, this has worked fine and we have not changed anything since the start. We are signing mach-o binaries built with go.

However, we now get the error:

configuration file error
  in profile: default
  problem key: app
  problem: UnknownField("app", ["sign", "remote-sign"])

Even though we do not provide a configuration file and the alpine container is always clean and empty when running. These are our steps to get rcodesign working:

    - apk add musl-dev curl wget tar
    - rustup target add x86_64-unknown-linux-musl
    - wget https://github.com/indygreg/apple-platform-rs/releases/download/apple-codesign%2F$VER/apple-codesign-$VER-x86_64-unknown-linux-musl.tar.gz
    - tar -xzf apple-codesign-$VER-x86_64-unknown-linux-musl.tar.gz
    - cp apple-codesign-$VER-x86_64-unknown-linux-musl/rcodesign /bin/rcodesign
    - chmod +x /bin/rcodesign

Until here, everything is just fine. However when we then run rcodesign against our binaries folder, we get the configuration file error.

- rcodesign sign --pem-source $RCODESIGN_DEVELOPER_CERTIFICATE --code-signature-flags runtime bin/*

As you can see, no config file is ever provided or created by us and we just use one of the simplest commands as provided in the documentation. This has worked fine before but is now broken, so I assume something must have changed between rcodesign releases. Is there some sort of default toml file created when running the command?

Maybe someone has a hint where to look or if there's a new flag missing in our command that we need to supply?