Terraform validate on Ephmereal outputs

[blazing234]

Terraform Version

V15

Terraform Configuration Files

Nothing relevant

Debug Output

...debug output, or link to a gist...

Expected Behavior

Terraform validate shouldn't error out with Ephmereal outputs for modules which are only intended to be used as remote modules.

Apparently this was fixed in PR #37850, but it still errors.

Actual Behavior

Ephmereal outputs are not allowed in the context of a root module.

Steps to Reproduce

Define an Ephmereal resource
Output resource as Ephmereal
Terraform validate

Additional Context

No response

References

No response

Generative AI / LLM assisted development?

No response

[jbardin]

Hi @blazing234,

The validate command works on a configuration as a whole, and hence expects the current module to be a valid root module. It may be possible to change the expectations of what validate can operate on, but that is a little more nuanced than just changing the validation rules of outputs. In the meantime, the terraform test command is intended to work on non-root modules as well, and will inherently run validation as part of the test process.

[blazing234]

In the terraform documentation, validate is said "is thus primarily useful for general verification of reusable modules"

But the existence of this error contradictes that doesn't it?

I'm confused if PR 37850 was supposed to fix this or not now.

But if terraform test is a drop in replacement guess I'll just to see if in my org it can be changed from validate to test

[jbardin]

You're right, there's probably some contradictory documentation out there still collected over the years, provider requirements being passed into child modules also have the same limitations with validate. PR #37850 doesn't change the behavior of validate, but one of the backport commits does make sure ephemeral outputs can be handled by terraform test.

I changed this to an enhancement since it is working as intended, but that's not to imply whether documentation should be fixed or whether the behavior could be changed.