Auto-detect digger-os and digger-arch from runner.os / runner.arch

[samuel-gamelin]

Problem

The digger-os and digger-arch inputs default to Linux and X64. The download step doesn't use GitHub's built-in runner.os / runner.arch contexts to resolve the correct binary. On non-x86 Linux or macOS self-hosted runners, this downloads the wrong binary.

Related: #2316 (same root cause on Linux ARM64)

Proposed fix

Change the input defaults to empty strings and auto-detect when not explicitly set. The release already publishes lowercase Go-convention binaries alongside the legacy Linux-X64 one:

digger-cli-linux-amd64    ✅
digger-cli-linux-arm64    ✅
digger-cli-darwin-amd64   ✅
digger-cli-darwin-arm64   ✅
digger-cli-windows-amd64  ✅

Auto-detection in the download step:

if [[ -z "$DIGGER_OS" ]]; then
  case "${{ runner.os }}" in
    Linux) DIGGER_OS="linux" ;;
    macOS) DIGGER_OS="darwin" ;;
    Windows) DIGGER_OS="windows" ;;
  esac
fi

if [[ -z "$DIGGER_ARCH" ]]; then
  case "${{ runner.arch }}" in
    X64) DIGGER_ARCH="amd64" ;;
    ARM64) DIGGER_ARCH="arm64" ;;
    ARM) DIGGER_ARCH="arm" ;;
    X86) DIGGER_ARCH="386" ;;
  esac
fi

This is backward-compatible — Linux X64 runners resolve to digger-cli-linux-amd64 which already exists. Self-hosted runners on other platforms work without manual configuration.

Current workaround

Manually set both inputs per workflow:

- uses: diggerhq/digger@v0.6.142
  with:
    digger-os: darwin
    digger-arch: arm64

Environment

• Self-hosted macOS ARM64 (Apple Silicon), digger v0.6.142

[s1ntaxe770r]

Hey @samuel-gamelin, thanks for opening this up. This seems like a reasonable approach. I'm curious, @sidpalas what do you think?