update CHANGELOG.md

CHANGELOG.md

@@ -21,6 +21,7 @@ NEW FEATURES:
 ENHANCEMENTS:
 
 * config: Terraform now checks the syntax of and normalizes module source addresses (the `source` argument in `module` blocks) during configuration decoding rather than only at module installation time. This is largely just an internal refactoring, but a visible benefit of this change is that the `terraform init` messages about module downloading will now show the canonical module package address Terraform is downloading from, after interpreting the special shorthands for common cases like GitHub URLs. ([#28854](https://github.com/hashicorp/terraform/issues/28854))
+* config: A new variable attribute `nullable`, which defines whether a variable can be null within a module. Setting `nullable` to `false` ensures that a variable value will not be `null`, and that a non-null default is used when `null` is given as a module argument [GH-29832]
 * `terraform plan` and `terraform apply`: Terraform will now report explicitly in the UI if it automatically moves a resource instance to a new address as a result of adding or removing the `count` argument from an existing resource. For example, if you previously had `resource "aws_subnet" "example"` _without_ `count`, you might have `aws_subnet.example` already bound to a remote object in your state. If you add `count = 1` to that resource then Terraform would previously silently rebind the object to `aws_subnet.example[0]` as part of planning, whereas now Terraform will mention that it did so explicitly in the plan description. ([#29605](https://github.com/hashicorp/terraform/issues/29605))
 * `terraform workspace delete`: will now allow deleting a workspace whose state contains only data resource instances and output values, without running `terraform destroy` first. Previously the presence of data resources would require using `-force` to override the safety check guarding against accidentally forgetting about remote objects, but a data resource is not responsible for the management of its associated remote object(s) anyway. ([#29754](https://github.com/hashicorp/terraform/issues/29754))
 * provisioner/remote-exec and provisioner/file: When using SSH agent authentication mode on Windows, Terraform can now detect and use [the Windows 10 built-in OpenSSH Client](https://devblogs.microsoft.com/powershell/using-the-openssh-beta-in-windows-10-fall-creators-update-and-windows-server-1709/)'s SSH Agent, when available, in addition to the existing support for the third-party solution [Pageant](https://documentation.help/PuTTY/pageant.html) that was already supported. ([#29747](https://github.com/hashicorp/terraform/issues/29747))