{"abstract":"An enclosed start reports zero reachable cells.","category":"Procedural level generation constraints","checks":8,"contract":"grid rows of '#' wall, '.' floor, 'D' door (passable), '~' water (passable only when swim) and 'E' exit. From start [row, col], 4-neighbour flood fill. Returns {reachable: number of reached cells including start, exit: whether an E cell was reached}.","contract_signature":"grid, start, swim","evaluation_group":"w2-procedural-level-generation-constraints-flood-reach","failed_approach":"Seeding with swapped coordinates marks the wrong cell as visited.","family":"w2-procedural-level-generation-constraints-flood-reach-start-seeding","id":"FA-86376","implementations":{"attempt":{"sha256":"201f5d35fb9960e1d5a2ca5fc10da98d4270e970f35c2e594801089f27499adb","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(grid, start, swim):\n    h = len(grid)\n    w = len(grid[0])\n    sr, sc = start\n    seen = {(sc, sr)}\n    stack = [(sr, sc)]\n    found = False\n    while stack:\n        r, c = stack.pop()\n        if grid[r][c] == 'E':\n            found = True\n        for dr, dc in ((1, 0), (-1, 0), (0, 1), (0, -1)):\n            nr, nc = r + dr, c + dc\n            if 0 <= nr < h and 0 <= nc < w and (nr, nc) not in seen:\n                t = grid[nr][nc]\n                if t == '#' or (t == '~' and not swim):\n                    continue\n                seen.add((nr, nc))\n                stack.append((nr, nc))\n    return {'reachable': len(seen), 'exit': found}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1', [['~.#D##E'], [0, 6], False], {'reachable': 1, 'exit': True}),\n  ('fault site start seeding #2',\n   [['DD~.', '.#.#', '~.E.', '#.~~', 'D.~.'], [4, 3], False],\n   {'reachable': 1, 'exit': False}),\n  ('partial repair boundary #1', [['E', '.'], [1, 0], False], {'reachable': 2, 'exit': True}),\n  ('partial repair boundary #2',\n   [['~.D#.', 'D....', '#.D#E'], [1, 4], True],\n   {'reachable': 12, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['.E..', '.D..'], [0, 1], True], {'reachable': 8, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1',\n   [['DD~.', '.#.#', '~.E.', '#.~~', 'D.~.'], [4, 3], False],\n   {'reachable': 1, 'exit': False}),\n  ('fault site start seeding #2', [['E'], [0, 0], False], {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1',\n   [['~.D#.', 'D....', '#.D#E'], [1, 4], True],\n   {'reachable': 12, 'exit': True}),\n  ('partial repair boundary #2',\n   [['D.~E.', '#~~.#', 'DD...'], [2, 3], False],\n   {'reachable': 8, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['.E..', '.D..'], [0, 1], True], {'reachable': 8, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1', [['E', '#', '~', '.'], [0, 0], True], {'reachable': 1, 'exit': True}),\n  ('fault site start seeding #2', [['E'], [0, 0], True], {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1', [['E', '.', '.', '.', '~'], [2, 0], True], {'reachable': 5, 'exit': True}),\n  ('partial repair boundary #2',\n   [['..', '.E', 'DD', '.#', '..', '.~', '..'], [6, 0], False],\n   {'reachable': 12, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['E.D.', '...D'], [1, 0], True], {'reachable': 8, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1',\n   [['#D~.##', '.D.~E#', '.~...~', '....#.', '#.....'], [0, 3], False],\n   {'reachable': 1, 'exit': False}),\n  ('fault site start seeding #2', [['E', '#'], [0, 0], False], {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1', [['~D.E..~', '.......'], [1, 5], False], {'reachable': 12, 'exit': True}),\n  ('partial repair boundary #2',\n   [['#D~..', '.#D.~', '.#...', '....D', 'DD#..', '.D.~#', '~~E.D'], [0, 3], True],\n   {'reachable': 30, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1',\n   [['.##.', '.D#D', 'D...', '.D~.', '.#DE', '.~#.', '.~DD'], [3, 0], False],\n   {'reachable': 20, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1',\n   [['.~~~D', 'E....', '.~.#D', '~.~#~', '~~D~D', '.#~#.'], [5, 0], False],\n   {'reachable': 1, 'exit': False}),\n  ('fault site start seeding #2',\n   [['D', '#', 'E', '#', '.', '.', '.'], [2, 0], True],\n   {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1',\n   [['.', '.', '~', 'E', '.', '~'], [4, 0], True],\n   {'reachable': 6, 'exit': True}),\n  ('partial repair boundary #2', [['E.D..'], [0, 3], False], {'reachable': 5, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['.E', '.D', 'D.'], [0, 0], True], {'reachable': 6, 'exit': True})]]\nfor label, args, expected in cases[N-1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"e58109cc58a9b7a5b18f0a3891d14b04c1969689de2ab49cbcb76cae60b4c303","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(grid, start, swim):\n    h = len(grid)\n    w = len(grid[0])\n    sr, sc = start\n    seen = set()\n    stack = [(sr, sc)]\n    found = False\n    while stack:\n        r, c = stack.pop()\n        if grid[r][c] == 'E':\n            found = True\n        for dr, dc in ((1, 0), (-1, 0), (0, 1), (0, -1)):\n            nr, nc = r + dr, c + dc\n            if 0 <= nr < h and 0 <= nc < w and (nr, nc) not in seen:\n                t = grid[nr][nc]\n                if t == '#' or (t == '~' and not swim):\n                    continue\n                seen.add((nr, nc))\n                stack.append((nr, nc))\n    return {'reachable': len(seen), 'exit': found}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1', [['~.#D##E'], [0, 6], False], {'reachable': 1, 'exit': True}),\n  ('fault site start seeding #2',\n   [['DD~.', '.#.#', '~.E.', '#.~~', 'D.~.'], [4, 3], False],\n   {'reachable': 1, 'exit': False}),\n  ('partial repair boundary #1', [['E', '.'], [1, 0], False], {'reachable': 2, 'exit': True}),\n  ('partial repair boundary #2',\n   [['~.D#.', 'D....', '#.D#E'], [1, 4], True],\n   {'reachable': 12, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['.E..', '.D..'], [0, 1], True], {'reachable': 8, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1',\n   [['DD~.', '.#.#', '~.E.', '#.~~', 'D.~.'], [4, 3], False],\n   {'reachable': 1, 'exit': False}),\n  ('fault site start seeding #2', [['E'], [0, 0], False], {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1',\n   [['~.D#.', 'D....', '#.D#E'], [1, 4], True],\n   {'reachable': 12, 'exit': True}),\n  ('partial repair boundary #2',\n   [['D.~E.', '#~~.#', 'DD...'], [2, 3], False],\n   {'reachable': 8, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['.E..', '.D..'], [0, 1], True], {'reachable': 8, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1', [['E', '#', '~', '.'], [0, 0], True], {'reachable': 1, 'exit': True}),\n  ('fault site start seeding #2', [['E'], [0, 0], True], {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1', [['E', '.', '.', '.', '~'], [2, 0], True], {'reachable': 5, 'exit': True}),\n  ('partial repair boundary #2',\n   [['..', '.E', 'DD', '.#', '..', '.~', '..'], [6, 0], False],\n   {'reachable': 12, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['E.D.', '...D'], [1, 0], True], {'reachable': 8, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1',\n   [['#D~.##', '.D.~E#', '.~...~', '....#.', '#.....'], [0, 3], False],\n   {'reachable': 1, 'exit': False}),\n  ('fault site start seeding #2', [['E', '#'], [0, 0], False], {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1', [['~D.E..~', '.......'], [1, 5], False], {'reachable': 12, 'exit': True}),\n  ('partial repair boundary #2',\n   [['#D~..', '.#D.~', '.#...', '....D', 'DD#..', '.D.~#', '~~E.D'], [0, 3], True],\n   {'reachable': 30, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1',\n   [['.##.', '.D#D', 'D...', '.D~.', '.#DE', '.~#.', '.~DD'], [3, 0], False],\n   {'reachable': 20, 'exit': True})],\n [('diagonal gap only #1', [['.#', '#E'], [0, 0], False], {'reachable': 1, 'exit': False}),\n  ('walled-in start #1', [['#.#', '#E#'], [0, 1], True], {'reachable': 2, 'exit': True}),\n  ('fault site start seeding #1',\n   [['.~~~D', 'E....', '.~.#D', '~.~#~', '~~D~D', '.#~#.'], [5, 0], False],\n   {'reachable': 1, 'exit': False}),\n  ('fault site start seeding #2',\n   [['D', '#', 'E', '#', '.', '.', '.'], [2, 0], True],\n   {'reachable': 1, 'exit': True}),\n  ('partial repair boundary #1',\n   [['.', '.', '~', 'E', '.', '~'], [4, 0], True],\n   {'reachable': 6, 'exit': True}),\n  ('partial repair boundary #2', [['E.D..'], [0, 3], False], {'reachable': 5, 'exit': True}),\n  ('door corridor #1', [['.DE'], [0, 0], False], {'reachable': 3, 'exit': True}),\n  ('control #1', [['.E', '.D', 'D.'], [0, 0], True], {'reachable': 6, 'exit': True})]]\nfor label, args, expected in cases[N-1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Deterministic toy contract stipulated for this model; integer or exact arithmetic only, not a reproduction of any specific game engine. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-procedural-level-generation-constraints-flood-reach-start-seeding","generated_at":"2026-09-29T14:50:48.927143+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Procedural generators silently emit unplayable or unfair levels when a single constraint check uses the wrong boundary, axis, neighborhood or update order; the defect is visible in exact generated geometry.","root_cause":"The visited set starts empty, so the start is counted only if a neighbour leads back.","sha256":"e7d520e5c9ef06c59cb37a1dee5ac58298f2ec935f294d157c46fa9fa54a8649","title":"Level reachability flood fill: Start cell is not counted · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":42.589,"exit_code":1,"observations":[{"actual":{"exit":false,"reachable":1},"check":"diagonal gap only #1","expected":{"exit":false,"reachable":1},"passed":true},{"actual":{"exit":true,"reachable":3},"check":"walled-in start #1","expected":{"exit":true,"reachable":2},"passed":false},{"actual":{"exit":true,"reachable":1},"check":"fault site start seeding #1","expected":{"exit":true,"reachable":1},"passed":true},{"actual":{"exit":false,"reachable":1},"check":"fault site start seeding #2","expected":{"exit":false,"reachable":1},"passed":true},{"actual":{"exit":true,"reachable":3},"check":"partial repair boundary #1","expected":{"exit":true,"reachable":2},"passed":false},{"actual":{"exit":true,"reachable":13},"check":"partial repair boundary #2","expected":{"exit":true,"reachable":12},"passed":false},{"actual":{"exit":true,"reachable":3},"check":"door corridor #1","expected":{"exit":true,"reachable":3},"passed":true},{"actual":{"exit":true,"reachable":8},"check":"control #1","expected":{"exit":true,"reachable":8},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"diagonal gap only #1\", \"actual\": {\"reachable\": 1, \"exit\": false}, \"expected\": {\"reachable\": 1, \"exit\": false}, \"passed\": true}, {\"check\": \"walled-in start #1\", \"actual\": {\"reachable\": 3, \"exit\": true}, \"expected\": {\"reachable\": 2, \"exit\": true}, \"passed\": false}, {\"check\": \"fault site start seeding #1\", \"actual\": {\"reachable\": 1, \"exit\": true}, \"expected\": {\"reachable\": 1, \"exit\": true}, \"passed\": true}, {\"check\": \"fault site start seeding #2\", \"actual\": {\"reachable\": 1, \"exit\": false}, \"expected\": {\"reachable\": 1, \"exit\": false}, \"passed\": true}, {\"check\": \"partial repair boundary #1\", \"actual\": {\"reachable\": 3, \"exit\": true}, \"expected\": {\"reachable\": 2, \"exit\": true}, \"passed\": false}, {\"check\": \"partial repair boundary #2\", \"actual\": {\"reachable\": 13, \"exit\": true}, \"expected\": {\"reachable\": 12, \"exit\": true}, \"passed\": false}, {\"check\": \"door corridor #1\", \"actual\": {\"reachable\": 3, \"exit\": true}, \"expected\": {\"reachable\": 3, \"exit\": true}, \"passed\": true}, {\"check\": \"control #1\", \"actual\": {\"reachable\": 8, \"exit\": true}, \"expected\": {\"reachable\": 8, \"exit\": true}, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.111,"exit_code":1,"observations":[{"actual":{"exit":false,"reachable":0},"check":"diagonal gap only #1","expected":{"exit":false,"reachable":1},"passed":false},{"actual":{"exit":true,"reachable":2},"check":"walled-in start #1","expected":{"exit":true,"reachable":2},"passed":true},{"actual":{"exit":true,"reachable":0},"check":"fault site start seeding #1","expected":{"exit":true,"reachable":1},"passed":false},{"actual":{"exit":false,"reachable":0},"check":"fault site start seeding #2","expected":{"exit":false,"reachable":1},"passed":false},{"actual":{"exit":true,"reachable":2},"check":"partial repair boundary #1","expected":{"exit":true,"reachable":2},"passed":true},{"actual":{"exit":true,"reachable":12},"check":"partial repair boundary #2","expected":{"exit":true,"reachable":12},"passed":true},{"actual":{"exit":true,"reachable":3},"check":"door corridor #1","expected":{"exit":true,"reachable":3},"passed":true},{"actual":{"exit":true,"reachable":8},"check":"control #1","expected":{"exit":true,"reachable":8},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"diagonal gap only #1\", \"actual\": {\"reachable\": 0, \"exit\": false}, \"expected\": {\"reachable\": 1, \"exit\": false}, \"passed\": false}, {\"check\": \"walled-in start #1\", \"actual\": {\"reachable\": 2, \"exit\": true}, \"expected\": {\"reachable\": 2, \"exit\": true}, \"passed\": true}, {\"check\": \"fault site start seeding #1\", \"actual\": {\"reachable\": 0, \"exit\": true}, \"expected\": {\"reachable\": 1, \"exit\": true}, \"passed\": false}, {\"check\": \"fault site start seeding #2\", \"actual\": {\"reachable\": 0, \"exit\": false}, \"expected\": {\"reachable\": 1, \"exit\": false}, \"passed\": false}, {\"check\": \"partial repair boundary #1\", \"actual\": {\"reachable\": 2, \"exit\": true}, \"expected\": {\"reachable\": 2, \"exit\": true}, \"passed\": true}, {\"check\": \"partial repair boundary #2\", \"actual\": {\"reachable\": 12, \"exit\": true}, \"expected\": {\"reachable\": 12, \"exit\": true}, \"passed\": true}, {\"check\": \"door corridor #1\", \"actual\": {\"reachable\": 3, \"exit\": true}, \"expected\": {\"reachable\": 3, \"exit\": true}, \"passed\": true}, {\"check\": \"control #1\", \"actual\": {\"reachable\": 8, \"exit\": true}, \"expected\": {\"reachable\": 8, \"exit\": true}, \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}