{
  "id": "environment-transaction",
  "version": "1.0.0",
  "title": "环境 plan → apply → rollback",
  "summary": "环境变更是事务：失败不得破坏当前环境，回滚只移动指针。",
  "steps": [
    "environment_transaction"
  ],
  "permissions": [
    "environment:apply"
  ],
  "artifacts": [],
  "failure_conditions": [
    "失败的构建改动了 current 指针",
    "回滚需要重建"
  ],
  "cases": [
    {
      "id": "environment-transaction/rollback",
      "title": "两代之后回滚到第一代",
      "outcome": "recovered",
      "inputs": {
        "environment_transaction": {
          "revisions": [
            "numpy\n",
            "numpy\npandas\n"
          ],
          "rollback_to_index": 0
        }
      },
      "expect": {
        "applied": 2
      }
    },
    {
      "id": "environment-transaction/failed-apply",
      "title": "构建失败后 current 必须不变",
      "outcome": "success",
      "inputs": {
        "environment_transaction": {
          "revisions": [
            "numpy\n",
            "numpy\nbroken\n"
          ],
          "fail_on_build": 2
        }
      },
      "expect": {
        "applied": 1
      }
    }
  ]
}