FAILURE MAP
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FA-86641 / Procedural level generation constraints / Open access

Boss room selection: Doors are one-way · case 01

Rooms behind doors listed backwards are never considered for the boss.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Only the forward adjacency is recorded.

THE FAILURE

Only the forward adjacency is recorded.

Unsuccessful approach: Recording reverse links only for ascending pairs still drops half the doors.

Case contract

Rooms 0..n-1 joined by two-way doors [a, b]. The boss room is the reachable room (other than start) with the largest BFS door distance from start, ties to the lowest room id. Returns [room, distance] or None when no other room is reachable.

Why this case matters

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.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(n, doors, start):
    adj = {i: [] for i in range(n)}
    for a, b in doors:
        adj[a].append(b)
        pass
    dist = {start: 0}
    queue = [start]
    for u in queue:
        for v in sorted(adj[u]):
            if v not in dist:
                dist[v] = dist[u] + 1
                queue.append(v)
    best = None
    for room, d in dist.items():
        if room == start:
            continue
        if best is None or d > best[1] or (d == best[1] and room < best[0]):
            best = [room, d]
    return best
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('fault site door symmetry #1', [6, [[0, 1], [1, 2], [1, 3], [1, 4], [2, 0], [1, 4]], 2], [3, 2]),
  ('regression door symmetry #1', [7, [[0, 1], [0, 2], [1, 3], [4, 0], [3, 5], [6, 2]], 1], [6, 3]),
  ('regression door symmetry #2', [6, [[1, 0], [0, 2], [3, 0], [4, 2], [3, 5]], 4], [5, 4]),
  ('regression door symmetry #3', [7, [[0, 1], [3, 0], [4, 1], [5, 4], [6, 5], [4, 0]], 4], [3, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [1, [], 0], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('regression door symmetry #1', [7, [[0, 1], [0, 2], [1, 3], [4, 0], [3, 5], [6, 2]], 1], [6, 3]),
  ('fault site door symmetry #1', [2, [[0, 1], [0, 1]], 1], [0, 1]),
  ('regression door symmetry #2', [6, [[1, 0], [0, 2], [3, 0], [4, 2], [3, 5]], 4], [5, 4]),
  ('regression door symmetry #3', [7, [[0, 1], [3, 0], [4, 1], [5, 4], [6, 5], [4, 0]], 4], [3, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [1, [], 0], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('fault site door symmetry #1', [8, [[0, 1], [1, 2], [1, 4], [5, 2], [3, 6], [7, 3], [3, 7]], 2], [0, 2]),
  ('regression door symmetry #1', [6, [[1, 0], [0, 2], [3, 0], [4, 2], [3, 5]], 4], [5, 4]),
  ('partial repair boundary #1', [4, [[0, 1], [2, 0], [1, 3], [2, 3], [0, 3]], 0], [1, 1]),
  ('regression door symmetry #2', [3, [[1, 0], [2, 1]], 0], [2, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [1, [], 0], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('regression door symmetry #1', [7, [[0, 1], [3, 0], [4, 1], [5, 4], [6, 5], [4, 0]], 4], [3, 2]),
  ('fault site door symmetry #1', [3, [[0, 1], [2, 1], [0, 1]], 2], [0, 2]),
  ('regression door symmetry #2', [6, [[2, 1], [3, 1], [1, 5]], 3], [2, 2]),
  ('regression door symmetry #3', [5, [[2, 1], [4, 2]], 1], [4, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [8, [[1, 0], [1, 3], [3, 4], [4, 5], [0, 6], [7, 4], [3, 7]], 2], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('fault site door symmetry #1', [4, [[0, 1], [0, 2], [0, 3], [1, 3], [2, 0]], 3], [2, 2]),
  ('regression door symmetry #1', [3, [[1, 0], [2, 1]], 0], [2, 2]),
  ('regression door symmetry #2', [4, [[1, 0], [2, 0], [3, 0]], 0], [1, 1]),
  ('regression door symmetry #3', [4, [[0, 2], [2, 1], [2, 0]], 1], [0, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [5, [[0, 1], [0, 2], [3, 0], [0, 3]], 4], None)]]
for label, args, expected in cases[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
door listed backwards #1None[1, 1]Failed
fault site door symmetry #1[3, 3][3, 2]Failed
regression door symmetry #1[5, 2][6, 3]Failed
regression door symmetry #2[2, 1][5, 4]Failed
regression door symmetry #3[0, 1][3, 2]Failed
two leaves tie #1[1, 1][1, 1]Passed
isolated start #1NoneNonePassed
control #1NoneNonePassed

SHA-256 / 4711c9a6b11cedc16ce9cbbc6ceeb8c7c5860d9565a77361f31ec42071de4249

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(n, doors, start):
    adj = {i: [] for i in range(n)}
    for a, b in doors:
        adj[a].append(b)
        adj[b].append(a) if a < b else None
    dist = {start: 0}
    queue = [start]
    for u in queue:
        for v in sorted(adj[u]):
            if v not in dist:
                dist[v] = dist[u] + 1
                queue.append(v)
    best = None
    for room, d in dist.items():
        if room == start:
            continue
        if best is None or d > best[1] or (d == best[1] and room < best[0]):
            best = [room, d]
    return best
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('fault site door symmetry #1', [6, [[0, 1], [1, 2], [1, 3], [1, 4], [2, 0], [1, 4]], 2], [3, 2]),
  ('regression door symmetry #1', [7, [[0, 1], [0, 2], [1, 3], [4, 0], [3, 5], [6, 2]], 1], [6, 3]),
  ('regression door symmetry #2', [6, [[1, 0], [0, 2], [3, 0], [4, 2], [3, 5]], 4], [5, 4]),
  ('regression door symmetry #3', [7, [[0, 1], [3, 0], [4, 1], [5, 4], [6, 5], [4, 0]], 4], [3, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [1, [], 0], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('regression door symmetry #1', [7, [[0, 1], [0, 2], [1, 3], [4, 0], [3, 5], [6, 2]], 1], [6, 3]),
  ('fault site door symmetry #1', [2, [[0, 1], [0, 1]], 1], [0, 1]),
  ('regression door symmetry #2', [6, [[1, 0], [0, 2], [3, 0], [4, 2], [3, 5]], 4], [5, 4]),
  ('regression door symmetry #3', [7, [[0, 1], [3, 0], [4, 1], [5, 4], [6, 5], [4, 0]], 4], [3, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [1, [], 0], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('fault site door symmetry #1', [8, [[0, 1], [1, 2], [1, 4], [5, 2], [3, 6], [7, 3], [3, 7]], 2], [0, 2]),
  ('regression door symmetry #1', [6, [[1, 0], [0, 2], [3, 0], [4, 2], [3, 5]], 4], [5, 4]),
  ('partial repair boundary #1', [4, [[0, 1], [2, 0], [1, 3], [2, 3], [0, 3]], 0], [1, 1]),
  ('regression door symmetry #2', [3, [[1, 0], [2, 1]], 0], [2, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [1, [], 0], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('regression door symmetry #1', [7, [[0, 1], [3, 0], [4, 1], [5, 4], [6, 5], [4, 0]], 4], [3, 2]),
  ('fault site door symmetry #1', [3, [[0, 1], [2, 1], [0, 1]], 2], [0, 2]),
  ('regression door symmetry #2', [6, [[2, 1], [3, 1], [1, 5]], 3], [2, 2]),
  ('regression door symmetry #3', [5, [[2, 1], [4, 2]], 1], [4, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [8, [[1, 0], [1, 3], [3, 4], [4, 5], [0, 6], [7, 4], [3, 7]], 2], None)],
 [('door listed backwards #1', [2, [[1, 0]], 0], [1, 1]),
  ('fault site door symmetry #1', [4, [[0, 1], [0, 2], [0, 3], [1, 3], [2, 0]], 3], [2, 2]),
  ('regression door symmetry #1', [3, [[1, 0], [2, 1]], 0], [2, 2]),
  ('regression door symmetry #2', [4, [[1, 0], [2, 0], [3, 0]], 0], [1, 1]),
  ('regression door symmetry #3', [4, [[0, 2], [2, 1], [2, 0]], 1], [0, 2]),
  ('two leaves tie #1', [3, [[0, 2], [0, 1]], 0], [1, 1]),
  ('isolated start #1', [3, [[1, 2]], 0], None),
  ('control #1', [5, [[0, 1], [0, 2], [3, 0], [0, 3]], 4], None)]]
for label, args, expected in cases[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
door listed backwards #1None[1, 1]Failed
fault site door symmetry #1[3, 2][3, 2]Passed
regression door symmetry #1[2, 2][6, 3]Failed
regression door symmetry #2[0, 2][5, 4]Failed
regression door symmetry #3[0, 1][3, 2]Failed
two leaves tie #1[1, 1][1, 1]Passed
isolated start #1NoneNonePassed
control #1NoneNonePassed

SHA-256 / 5ca91d2c78f8e7f33db992e2a36bfcce686a2eb3094f982641b2a3a56bdaba42

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:50:51.412748+00:00.

Case digest / 90d62a5f14f73643dcd72acd2213309f5b98b82a2de90b7a02b4b78dc6b4fe20