{
  "slug": "terragrunt-cas-integrates-with-stacks-through-update-source-with-cas-76df6b7a5d14",
  "title": "terragrunt CAS integrates with stacks through update_source_with_cas",
  "tools": [
    "terragrunt"
  ],
  "tags": [
    "agent"
  ],
  "introduced_at": "2026-04-27T14:17:59.000Z",
  "announced_at": "2026-04-27T14:17:59.000Z",
  "effective_at": null,
  "date_basis": "source-publication",
  "status": "unknown",
  "how": {
    "incantation": "When a catalog unit uses a relative source path, set `update_source_with_cas = true` and generate the stack with CAS enabled; Terragrunt rewrites the source to a `cas::` reference. The v1.0.3 release note says to enable the `cas` experiment, but current documentation no longer lists CAS as an experiment.",
    "examples": [
      "unit \"service\" {\n  source = \"../..//units/my-service\"\n  update_source_with_cas = true\n  path = \"service\"\n}\n\nterragrunt stack generate --experiment cas"
    ],
    "gotchas": [
      "Version: v1.0.3",
      "Availability: The `cas` experiment is required.",
      "source (required): Relative source path within the same repository; `//` separates the repository base path from the subdirectory.",
      "update_source_with_cas: Set to `true` to rewrite a nested relative source to a `cas::` reference during stack generation.",
      "path (required): Relative destination path for the generated unit.",
      "stack generate (required): Generates stack units from discovered `terragrunt.stack.hcl` configurations.",
      "Prerequisite: The relative source must stay within the same repository; `--no-cas` must not be set.",
      "Prerequisite: The v1.0.3 release note says the `cas` experiment must be enabled. Current active-experiment docs do not list CAS as an experiment.",
      "The repository is cloned once; subsequent stack generations resolve content from the local store without network access.",
      "Docs conflict: Current documentation describes CAS integration but no longer documents the `cas` experiment enable flag; it may describe behavior newer than v1.0.3."
    ]
  },
  "why_it_matters": "Generate a stack from catalog units whose Terraform source paths are relative to the catalog repository.",
  "before": "Without CAS, catalog authors used remote Git URLs and threaded the reference through `values` expressions.",
  "sources": [
    "https://github.com/gruntwork-io/terragrunt/releases/tag/v1.0.3",
    "https://docs.terragrunt.com/features/stacks/explicit/",
    "https://docs.terragrunt.com/reference/cli/commands/stack/generate/"
  ],
  "rank": 0.96034,
  "judge": {
    "publish": true,
    "judge_model": "codex-cli/gpt-6-luna+typesafe/jev-1.13.0",
    "prompt_version": "extract-v7+enrich-v2+judge-v2x3+jev-publish-v1"
  },
  "review_state": "approved",
  "provenance": {
    "run_id": "wave2a-20261017",
    "verdict_id": "wave2a-20261017:wave2a-20261017-fcea54bb20ea13c8-2:gate",
    "evidence_hash": "971f980a841953c3c89a14d88ab2e29c72ffa049e94b2f40e9a648581d136a5a"
  },
  "review": {
    "draft_hash": "29a2afae69a08ea7f5167815544f3e54af0ccd10d90af402ec4689f2e90e63f6",
    "reviewer": "publication-gate",
    "reviewed_at": "2026-10-07T00:00:00.000Z",
    "decision": "wave2a-20261017:gate",
    "reason": "3 of 3 judge runs approved with p_yes >= 0.9 (mean 0.96 >= 0.9; 2 needed) and Jev gave 0.63 (>= 0.6 needed)."
  }
}