OpenTofu environment variables start with TF_, not TOFU_

[pib]

What happened?

The OpenTofu provider fails to load a provided .tofurc config file, and so it fails to authenticate against a private Terraform module repository.

Upon investigation I see that the provider seems to be setting TOFU_CLI_CONFIG_FILE=./.tofurc (https://github.com/upbound/provider-opentofu/blob/main/internal/opentofu/opentofu.go#L187), but according to the OpenTofu docs, it should be setting TF_CLI_CONFIG_FILE: https://opentofu.org/docs/v1.8/cli/config/environment-variables/#tf_cli_config_file

I confirmed this by running a local tofu init -from-module with both env var names, and only the TF_ one works.

It looks like this would also mean that the plugin cache dir setting will also not function as expected, but I haven't tested that: https://github.com/upbound/provider-opentofu/blob/main/internal/opentofu/opentofu.go#L180

How can we reproduce it?

• Follow the .tofurc config example in the docs with a token for a private module repo in the config: https://github.com/upbound/provider-opentofu/blob/main/docs/monolith/Configuration.md#tofurc-repository-support
• Create a Workspace with TF that includes a module from that private repo.
• Get a "Failed to retrieve available versions for module ... error looking up module versions: 401 Unauthorized." error.

What environment did it happen in?

I'm using v0.2.1, but it looks like any version would have the same issue.

[pib]

I have verified that switching to TF_CLI_CONFIG_FILE fixes the issue. I built and pushed to a private repo a fixed provider version, and after switching to that version, the issue was fixed.

[jeanduplessis]

@pib thanks for identifying the problem and fix. Would you be willing to open a PR to fix this bug in the repo?