{
  "schema_version": 1,
  "date": "2026-09-20",
  "before_source_commit": "a9b99f4aeb973310a73d89fada026536b97d48d0",
  "after_source_commit": "dd7b36122354da8984be73c228bc5dc47d814d28",
  "scope": "Independent isolated synthetic comparison of the historical label-filtered builder and repaired shared current-feature transform. No model inference or training.",
  "feature": "momentum_1h_rank",
  "issue_bucket_ts": 1783040400,
  "issue_available_at_ts": 1783040700,
  "items": [
    {
      "item_id": 1,
      "label": "Item A"
    },
    {
      "item_id": 2,
      "label": "Item B"
    }
  ],
  "fixture": {
    "current_bars": 26,
    "bars_per_item": 13,
    "bar_seconds": 300,
    "horizon_seconds": 14400,
    "metadata_available_at_ts": 1783036800,
    "current_daily_volume": 10000,
    "volume_available_at_ts": 1783036800,
    "metadata_note": "Synthetic metadata explicitly observed at fixture start. The historical adapter receives the same item/name/limit values without an availability field. This is not reconstructed real metadata."
  },
  "cases": [
    {
      "name": "both_future_bars",
      "item_b_future_bar": true,
      "before": {
        "status": "ok",
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 1.0,
            "daily_volume": 10000.0
          },
          {
            "item_id": 2,
            "momentum_1h_rank": 0.0,
            "daily_volume": 10000.0
          }
        ]
      },
      "after": {
        "status": "ok",
        "current_row_count": 26,
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 1.0,
            "daily_volume": 10000.0
          },
          {
            "item_id": 2,
            "momentum_1h_rank": 0.0,
            "daily_volume": 10000.0
          }
        ],
        "labels_at_issue": [
          {
            "item_id": 1,
            "target_return_known": true
          },
          {
            "item_id": 2,
            "target_return_known": true
          }
        ],
        "current_prefix_equal_to_reference": true,
        "retrospective_prefix_equal_to_current": true
      }
    },
    {
      "name": "remove_item2_future",
      "item_b_future_bar": false,
      "before": {
        "status": "ok",
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 0.0,
            "daily_volume": 10000.0
          }
        ]
      },
      "after": {
        "status": "ok",
        "current_row_count": 26,
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 1.0,
            "daily_volume": 10000.0
          },
          {
            "item_id": 2,
            "momentum_1h_rank": 0.0,
            "daily_volume": 10000.0
          }
        ],
        "labels_at_issue": [
          {
            "item_id": 1,
            "target_return_known": true
          },
          {
            "item_id": 2,
            "target_return_known": false
          }
        ],
        "current_prefix_equal_to_reference": true,
        "retrospective_prefix_equal_to_current": true
      }
    },
    {
      "name": "no_future_bars",
      "item_b_future_bar": false,
      "before": {
        "status": "error",
        "error_type": "TypeError"
      },
      "after": {
        "status": "ok",
        "current_row_count": 26,
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 1.0,
            "daily_volume": 10000.0
          },
          {
            "item_id": 2,
            "momentum_1h_rank": 0.0,
            "daily_volume": 10000.0
          }
        ],
        "labels_at_issue": [
          {
            "item_id": 1,
            "target_return_known": false
          },
          {
            "item_id": 2,
            "target_return_known": false
          }
        ],
        "current_prefix_equal_to_reference": true,
        "retrospective_prefix_equal_to_current": true
      }
    },
    {
      "name": "append_future_volume",
      "item_b_future_bar": true,
      "before": {
        "status": "ok",
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 0.0,
            "daily_volume": 20000.0
          }
        ]
      },
      "after": {
        "status": "ok",
        "current_row_count": 26,
        "rows_at_issue": [
          {
            "item_id": 1,
            "momentum_1h_rank": 1.0,
            "daily_volume": 10000.0
          },
          {
            "item_id": 2,
            "momentum_1h_rank": 0.0,
            "daily_volume": 10000.0
          }
        ],
        "labels_at_issue": [
          {
            "item_id": 1,
            "target_return_known": true
          },
          {
            "item_id": 2,
            "target_return_known": true
          }
        ],
        "current_prefix_equal_to_reference": true,
        "retrospective_prefix_equal_to_current": true
      }
    }
  ],
  "limits": [
    "Feature percentiles, not predicted rankings or model quality.",
    "All 26 current rows and their feature values including missingness match across tested future perturbations.",
    "Short synthetic history includes missing longer-window features; the fixture does not establish model-ready inputs.",
    "No compatible model was loaded or trained, no historical score recomputed and no MMG deployment performed."
  ]
}