cdktn CLI ignores terraformBinaryName / CDKTF_TERRAFORM_BINARY_NAME in GitHub Actions

[jjrawlins]

Description

When running cdktn deploy or cdktn diff in GitHub Actions with OpenTofu installed (via opentofu/setup-opentofu@v1), the CLI fails to resolve the tofu binary even when configured via:

1. terraformBinaryName: "tofu" in cdktf.json
2. CDKTF_TERRAFORM_BINARY_NAME=tofu environment variable
3. TERRAFORM_BINARY_NAME=tofu environment variable (per docs)

The CLI still attempts to spawn terraform and fails with ENOENT.

Workaround

Symlinking tofu as terraform:

- name: Symlink tofu as terraform
  run: ln -sf $(which tofu) /usr/local/bin/terraform

Expected Behavior

The CLI should honor terraformBinaryName from cdktf.json or the CDKTF_TERRAFORM_BINARY_NAME / TERRAFORM_BINARY_NAME environment variables and use the configured binary name when spawning Terraform/OpenTofu subprocesses.

Environment

• cdktn-cli: latest (installed via npm)
• OpenTofu: installed via opentofu/setup-opentofu@v1
• Platform: GitHub Actions (ubuntu-latest)
• Node.js: LTS