Cas Mutable Sources

cas — mutable attribute on terraform, unit, and stack blocks

A new mutable attribute opts a block out of CAS hardlinking when its source is fetched through CAS. With mutable = true, files materialized into .terragrunt-cache (for terraform) or .terragrunt-stack (for unit and stack) are copied from the CAS store and the working tree is editable.

The default is false. Files are materialized read-only so an accidental edit cannot reach back into the shared CAS store.

terraform {
  source  = "git::https://github.com/acme/infrastructure-modules.git//vpc?ref=v1.0.0"
  mutable = true
}

The flag is orthogonal to update_source_with_cas and has no effect when content is fetched through the standard download path, which already produces an independent copy.