Summary

• allow tasks to define their own vars that override global ones
• test task-local vars referencing globals

Testing

• go test ./...

Prompt

Task 11: Support Nested vars Blocks Within Tasks

Purpose:
Enable task-scoped variable definitions via vars blocks inside individual task definitions. This allows task-local variables that override or extend global ones and participate in the same expression resolution model.

Requirements:

• Each task block may contain its own vars block.
• The semantics of task-scoped vars should follow the same lazy evaluation and recursive resolution rules as global variables.
• Task-local variables may refer to global variables via vars.X, and vice versa is not allowed.
• The task-scoped vars must be evaluated in a merged context (global + local), with local vars taking precedence.
• Dynamic typing and expression support must be preserved in the task-level vars.

Examples to Support:

vars {
  ABC = 123
}

task "hi" {
  vars {
    DEF = 456
    GHI = "${vars.ABC}${vars.DEF}"
  }
}

Assert:

• vars.ABC == 123
• vars.DEF == 456 (only within task hi)
• vars.GHI == "123456" (in task hi only)

Scope:

• Applies only to the vars block (not env) inside tasks.
• Only variables defined in a task block's vars should shadow globals.
• Resolution behavior must follow the recursive logic from Task 9, using the merged context.

Implementation Notes (Do Not Copy Code):

• During decoding, task-level vars should be parsed as hcl.Expression like global vars.
• During task execution, merge the global variable context with the task-local context to form a unified evaluator.
• Ensure memoization and cycle detection respects the local vs global separation.
• Preserve HCL source range on all expressions for consistent error messages.

Validation:

• Add a test to HCLE2ETest that defines global vars, and a task with additional vars.
• Confirm:
  • Global variables are available inside tasks.
  • Task-local variables can override or extend global ones.
  • Combined interpolations (like ${vars.ABC}${vars.DEF}) resolve as expected.
• Test that a task referencing only local variables behaves the same way.
• Test invalid references (e.g., task-local vars attempting to override global env) and validate that appropriate errors or rejections occur.
• Confirm that the scope of task-level vars is isolated and does not leak between tasks.

https://chatgpt.com/codex/tasks/task_e_68924507f3508330b1b9e26a2cb6344d