Explicit inherit requirement introduced in Terramate 0.12 for stack variable propagation

Goal: Determine the exact scope of the explicit inherit block requirement added in Terramate 0.12 and identify whether any variable sources remain exempt from this rule.

Constraints: The change affects all projects using Terramate 0.12 or later, modifies existing terramate.hcl files that previously relied on implicit parent‑to‑child variable propagation, and can cause CI/CD failures if the inherit blocks are not added.

Uncertainty: While the documentation states that variables must be declared with an explicit inherit block, it is not clear if this applies universally to Terraform input variables, environment variables, or variables defined by generators and scripts, or if certain sources still allow implicit access.

• Does the explicit inherit requirement apply to variables defined in the root terramate.hcl vars block?
• Are Terraform input variables or environment variables exempt from needing an inherit block?
• If a child stack references a variable set only by a terramate script or generator, must an inherit block still be added?