terraform init log timestamps include millisecond precision

[Emyrk]

Terraform init json logs to include millisecond precision. Following the trend of other logs.

Example output:

{"@level":"info","@message":"Terraform 1.13.3","@module":"terraform.ui","@timestamp":"2025-10-27T12:48:29.576675-05:00","terraform":"1.13.3","type":"version","ui":"1.2"}
{"@level":"info","@message":"Initializing the backend...","@module":"terraform.ui","@timestamp":"2025-10-27T17:48:29Z","message_code":"initializing_backend_message","type":"init_output"}

The timestamps for init_output omit milliseconds.

Target Release

1.15.x

CHANGELOG entry

• This change is user-facing and I added a changelog entry.
• This change is not user-facing.

[hashicorp-cla-app]

All committers have signed the CLA.

[hashicorp-cla-app]

Thank you for your submission! We require that all contributors sign our Contributor License Agreement ("CLA") before we can accept the contribution. Read and sign the agreement

Learn more about why HashiCorp requires a CLA and what the CLA includes

_{Have you signed the CLA already but the status is still pending? Recheck it.}

[SarahFrench]

Hi @Emyrk, thank you for identifying this inconsistency and proposing a fix! I'm asking around internally about whether this would be a breaking change for our systems that consume these logs, and once I know more I'll report back.

[Emyrk]

Hi @Emyrk, thank you for identifying this inconsistency and proposing a fix! I'm asking around internally about whether this would be a breaking change for our systems that consume these logs, and once I know more I'll report back.

Thank you! Feel free to take over this PR or open a new one. These are logs I was attempting to use, but without the ms precision, the value was removed. Since many init operations take <1s.

[SarahFrench]

Thanks for bearing with me on this! Given the tests here and some internal conversations with people who work on HCP Terraform I'm happy to go ahead and merge this. Thanks again 🚀

[Emyrk]

@SarahFrench thank you!

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.