{
  "comment": "stored: a pre-migration v8 document — a room whose top wall carries a door and is fully covered by a legacy open_span; migrated: the same document after the current initial migration (#316 §3.1) — the door keeps its carrying atom, the border is zero on both sides. The golden scene renders `migrated`; the unit test pins it to the real writer byte for byte.",
  "stored": {
    "model_version": 8,
    "spaces": [
      {
        "id": "golden-span-over-door",
        "title": "Span over door",
        "cell_cm": 5,
        "view_box": [
          0,
          0,
          1,
          0.7
        ],
        "settings": {
          "fill_mode": "none",
          "show_borders": true,
          "show_names": true
        },
        "rooms": [
          {
            "id": "sod-room",
            "name": "Room",
            "area": null,
            "poly": [
              [
                0.2,
                0.3
              ],
              [
                0.6,
                0.3
              ],
              [
                0.6,
                0.6
              ],
              [
                0.2,
                0.6
              ]
            ]
          }
        ],
        "walls": [
          {
            "key": "0.400000,0.300000@0.0000",
            "a": [
              0.2,
              0.3
            ],
            "b": [
              0.6,
              0.3
            ],
            "cm": 15
          }
        ],
        "open_spans": [
          {
            "a": [
              0.2,
              0.3
            ],
            "b": [
              0.6,
              0.3
            ]
          }
        ],
        "openings": [
          {
            "id": "sod-door",
            "type": "door",
            "x": 0.4,
            "y": 0.3,
            "angle": 0,
            "length": 0.09,
            "cm": 90,
            "flip_v": true
          }
        ]
      }
    ],
    "markers": [],
    "settings": {}
  },
  "migrated": {
    "model_version": 10,
    "spaces": [
      {
        "id": "golden-span-over-door",
        "title": "Span over door",
        "cell_cm": 5,
        "view_box": [
          0,
          0,
          1,
          0.7
        ],
        "settings": {
          "fill_mode": "none",
          "show_borders": true,
          "show_names": true
        },
        "rooms": [
          {
            "id": "sod-room",
            "name": "Room",
            "area": null,
            "poly": [
              [
                0.2,
                0.3
              ],
              [
                0.355,
                0.3
              ],
              [
                0.445,
                0.3
              ],
              [
                0.6,
                0.3
              ],
              [
                0.6,
                0.6
              ],
              [
                0.2,
                0.6
              ]
            ],
            "wall_ids": [
              "wall-s2g2iw3nbbxkym6sodv4",
              "wall-qmhko777ctlb3hey6c3v",
              "wall-odwfy5lyxkwsum2jewma",
              "wall-l3r6mytgo2l4so24dljp",
              "wall-mzbb6mwcqxj67rhw7mc5",
              "wall-uyhvjlqcorfj3orzvhhj"
            ]
          }
        ],
        "walls": [
          {
            "key": "0.400000,0.300000@0.0000",
            "cm": 15,
            "a": [
              0.355,
              0.3
            ],
            "b": [
              0.445,
              0.3
            ]
          }
        ],
        "openings": [
          {
            "id": "sod-door",
            "type": "door",
            "x": 0.4,
            "y": 0.3,
            "angle": 0,
            "length": 0.09,
            "cm": 90,
            "flip_v": true,
            "host": {
              "kind": "wall",
              "id": "wall-qmhko777ctlb3hey6c3v",
              "t": 0.5
            }
          }
        ],
        "wall_segments": [
          {
            "id": "wall-uyhvjlqcorfj3orzvhhj",
            "a": [
              0.2,
              0.3
            ],
            "b": [
              0.2,
              0.6
            ],
            "cm": 0
          },
          {
            "id": "wall-s2g2iw3nbbxkym6sodv4",
            "a": [
              0.2,
              0.3
            ],
            "b": [
              0.355,
              0.3
            ],
            "cm": 0
          },
          {
            "id": "wall-mzbb6mwcqxj67rhw7mc5",
            "a": [
              0.2,
              0.6
            ],
            "b": [
              0.6,
              0.6
            ],
            "cm": 0
          },
          {
            "id": "wall-qmhko777ctlb3hey6c3v",
            "a": [
              0.355,
              0.3
            ],
            "b": [
              0.445,
              0.3
            ],
            "cm": 15
          },
          {
            "id": "wall-odwfy5lyxkwsum2jewma",
            "a": [
              0.445,
              0.3
            ],
            "b": [
              0.6,
              0.3
            ],
            "cm": 0
          },
          {
            "id": "wall-l3r6mytgo2l4so24dljp",
            "a": [
              0.6,
              0.3
            ],
            "b": [
              0.6,
              0.6
            ],
            "cm": 0
          }
        ]
      }
    ],
    "markers": [],
    "settings": {}
  }
}