FA-86616 / Procedural level generation constraints / Open access
Treasure dead-end finder: Treasure placed on the exit · case 01
The exit tile is reported as a treasure dead end.
ROOT CAUSE
Only the start is excluded.
VERIFIED REPAIR
Restore `[r, c] in (start, exit)` at the reserved cells step.
Unsuccessful approach: Comparing a tuple to list coordinates never matches.
Case contract
Cells: '#' wall, '~' chasm (not walkable), '.' floor, 'D' door (walkable). A dead end is a '.' cell, other than start and exit ([row, col] lists), with exactly one walkable in-bounds 4-neighbour. Returns dead ends in row-major order.
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(grid, start, exit):
h = len(grid)
w = len(grid[0])
ends = []
for r in range(h):
for c in range(w):
if grid[r][c] != '.' or [r, c] == start:
continue
n = 0
for dr, dc in ((1, 0), (-1, 0), (0, 1), (0, -1)):
rr, cc = r + dr, c + dc
if 0 <= rr < h and 0 <= cc < w and grid[rr][cc] in '.D':
n += 1
if n == 1:
ends.append([r, c])
return ends
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression reserved cells #1', [['~.##.', 'D..#~', '...##'], [0, 3], [0, 1]], []),
('regression reserved cells #2',
[['#D...D', '#D#...', '##.##.', '#.##.#', '#D##.~', 'D.#...'], [2, 5], [5, 3]],
[[3, 1], [3, 4], [5, 5]]),
('partial repair boundary #1', [['..#...', '~..##.', '##~##.'], [0, 0], [0, 5]], [[0, 3], [1, 2], [2, 5]]),
('partial repair boundary #2', [['.##', '#..'], [1, 2], [0, 1]], [[1, 1]]),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('control #1', [['#.#.#', '.#D~~', '..~..', '..D.~'], [1, 4], [2, 0]], [[1, 0], [2, 4]])],
[('regression reserved cells #1', [['.#...~', '.#.D~D', '....##'], [1, 0], [0, 0]], [[0, 4]]),
('regression reserved cells #2', [['#.', '..', '##', '##', '##'], [0, 0], [1, 0]], [[0, 1]]),
('partial repair boundary #1', [['.##', '#..'], [1, 2], [0, 1]], [[1, 1]]),
('regression reserved cells #3',
[['#D...D', '#D#...', '##.##.', '#.##.#', '#D##.~', 'D.#...'], [2, 5], [5, 3]],
[[3, 1], [3, 4], [5, 5]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('control #1', [['#.#.#', '.#D~~', '..~..', '..D.~'], [1, 4], [2, 0]], [[1, 0], [2, 4]]),
('control #2', [['...D#~', '~.###~', '~..D..'], [1, 3], [0, 2]], [[0, 0], [2, 5]])],
[('regression reserved cells #1', [['#~.~.', '..#~.', '#.D.~', '~#~..'], [1, 4], [1, 0]], [[0, 4], [3, 4]]),
('regression reserved cells #2',
[['..#.D.', '~~D###', '...##.', '...DD~', 'D~.DD#', 'D..~D~'], [0, 4], [0, 0]],
[[0, 1], [0, 3], [0, 5]]),
('regression reserved cells #3', [['.#...~', '.#.D~D', '....##'], [1, 0], [0, 0]], [[0, 4]]),
('regression reserved cells #4', [['#.', '..', '##', '##', '##'], [0, 0], [1, 0]], [[0, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('control #1', [['...D#~', '~.###~', '~..D..'], [1, 3], [0, 2]], [[0, 0], [2, 5]]),
('control #2', [['#~.#.', '#...D', 'D.#..', '#....', '##..~'], [3, 0], [3, 3]], [[0, 2], [0, 4]])],
[('regression reserved cells #1', [['..', '.#'], [1, 1], [1, 0]], [[0, 1]]),
('regression reserved cells #2',
[['..~', '.~#', '#D~', '###', 'D.#', '.#~'], [1, 1], [5, 0]],
[[0, 1], [1, 0], [4, 1]]),
('regression reserved cells #3', [['#~.~.', '..#~.', '#.D.~', '~#~..'], [1, 4], [1, 0]], [[0, 4], [3, 4]]),
('partial repair boundary #1',
[['#.', '#.', '#.', '.#', '..', '~.'], [2, 1], [1, 0]],
[[0, 1], [3, 0], [5, 1]]),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('control #1', [['~D.#D', '#.#~.'], [0, 1], [1, 2]], [[0, 2], [1, 1], [1, 4]]),
('control #2', [['.~~##.', '##~DD~'], [0, 1], [1, 0]], [])],
[('regression reserved cells #1', [['~.#.~', '..#D.', '~##..'], [2, 4], [0, 3]], [[0, 1], [1, 0]]),
('regression reserved cells #2', [['D.DD', '~.##', '.###', '#.~.', '#DD~'], [2, 3], [3, 1]], [[1, 1]]),
('partial repair boundary #1', [['..~..D', '....#.'], [1, 5], [0, 2]], []),
('regression reserved cells #3',
[['..#.D.', '~~D###', '...##.', '...DD~', 'D~.DD#', 'D..~D~'], [0, 4], [0, 0]],
[[0, 1], [0, 3], [0, 5]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('control #1', [['...#~.', 'D.~~.D'], [1, 1], [1, 1]], [[0, 2], [0, 5], [1, 4]]),
('control #2', [['##.#.', '.~#D.', 'D#.~#'], [0, 3], [1, 4]], [[0, 4], [1, 0]])]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| regression reserved cells #1 | [[0, 1]] | [] | Failed |
| regression reserved cells #2 | [[3, 1], [3, 4], [5, 3], [5, 5]] | [[3, 1], [3, 4], [5, 5]] | Failed |
| partial repair boundary #1 | [[0, 3], [1, 2], [2, 5]] | [[0, 3], [1, 2], [2, 5]] | Passed |
| partial repair boundary #2 | [[1, 1]] | [[1, 1]] | Passed |
| door as neighbour #1 | [[1, 1]] | [[1, 1]] | Passed |
| chasm edge #1 | [[0, 0], [0, 2]] | [[0, 0], [0, 2]] | Passed |
| isolated floor #1 | [] | [] | Passed |
| control #1 | [[1, 0], [2, 4]] | [[1, 0], [2, 4]] | Passed |
SHA-256 / e74794e918bd79c4998a091e6ea78ec6e96cca83450c00e023cdcb83047cccc0
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(grid, start, exit):
h = len(grid)
w = len(grid[0])
ends = []
for r in range(h):
for c in range(w):
if grid[r][c] != '.' or (r, c) in (start, exit):
continue
n = 0
for dr, dc in ((1, 0), (-1, 0), (0, 1), (0, -1)):
rr, cc = r + dr, c + dc
if 0 <= rr < h and 0 <= cc < w and grid[rr][cc] in '.D':
n += 1
if n == 1:
ends.append([r, c])
return ends
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression reserved cells #1', [['~.##.', 'D..#~', '...##'], [0, 3], [0, 1]], []),
('regression reserved cells #2',
[['#D...D', '#D#...', '##.##.', '#.##.#', '#D##.~', 'D.#...'], [2, 5], [5, 3]],
[[3, 1], [3, 4], [5, 5]]),
('partial repair boundary #1', [['..#...', '~..##.', '##~##.'], [0, 0], [0, 5]], [[0, 3], [1, 2], [2, 5]]),
('partial repair boundary #2', [['.##', '#..'], [1, 2], [0, 1]], [[1, 1]]),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('control #1', [['#.#.#', '.#D~~', '..~..', '..D.~'], [1, 4], [2, 0]], [[1, 0], [2, 4]])],
[('regression reserved cells #1', [['.#...~', '.#.D~D', '....##'], [1, 0], [0, 0]], [[0, 4]]),
('regression reserved cells #2', [['#.', '..', '##', '##', '##'], [0, 0], [1, 0]], [[0, 1]]),
('partial repair boundary #1', [['.##', '#..'], [1, 2], [0, 1]], [[1, 1]]),
('regression reserved cells #3',
[['#D...D', '#D#...', '##.##.', '#.##.#', '#D##.~', 'D.#...'], [2, 5], [5, 3]],
[[3, 1], [3, 4], [5, 5]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('control #1', [['#.#.#', '.#D~~', '..~..', '..D.~'], [1, 4], [2, 0]], [[1, 0], [2, 4]]),
('control #2', [['...D#~', '~.###~', '~..D..'], [1, 3], [0, 2]], [[0, 0], [2, 5]])],
[('regression reserved cells #1', [['#~.~.', '..#~.', '#.D.~', '~#~..'], [1, 4], [1, 0]], [[0, 4], [3, 4]]),
('regression reserved cells #2',
[['..#.D.', '~~D###', '...##.', '...DD~', 'D~.DD#', 'D..~D~'], [0, 4], [0, 0]],
[[0, 1], [0, 3], [0, 5]]),
('regression reserved cells #3', [['.#...~', '.#.D~D', '....##'], [1, 0], [0, 0]], [[0, 4]]),
('regression reserved cells #4', [['#.', '..', '##', '##', '##'], [0, 0], [1, 0]], [[0, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('control #1', [['...D#~', '~.###~', '~..D..'], [1, 3], [0, 2]], [[0, 0], [2, 5]]),
('control #2', [['#~.#.', '#...D', 'D.#..', '#....', '##..~'], [3, 0], [3, 3]], [[0, 2], [0, 4]])],
[('regression reserved cells #1', [['..', '.#'], [1, 1], [1, 0]], [[0, 1]]),
('regression reserved cells #2',
[['..~', '.~#', '#D~', '###', 'D.#', '.#~'], [1, 1], [5, 0]],
[[0, 1], [1, 0], [4, 1]]),
('regression reserved cells #3', [['#~.~.', '..#~.', '#.D.~', '~#~..'], [1, 4], [1, 0]], [[0, 4], [3, 4]]),
('partial repair boundary #1',
[['#.', '#.', '#.', '.#', '..', '~.'], [2, 1], [1, 0]],
[[0, 1], [3, 0], [5, 1]]),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('control #1', [['~D.#D', '#.#~.'], [0, 1], [1, 2]], [[0, 2], [1, 1], [1, 4]]),
('control #2', [['.~~##.', '##~DD~'], [0, 1], [1, 0]], [])],
[('regression reserved cells #1', [['~.#.~', '..#D.', '~##..'], [2, 4], [0, 3]], [[0, 1], [1, 0]]),
('regression reserved cells #2', [['D.DD', '~.##', '.###', '#.~.', '#DD~'], [2, 3], [3, 1]], [[1, 1]]),
('partial repair boundary #1', [['..~..D', '....#.'], [1, 5], [0, 2]], []),
('regression reserved cells #3',
[['..#.D.', '~~D###', '...##.', '...DD~', 'D~.DD#', 'D..~D~'], [0, 4], [0, 0]],
[[0, 1], [0, 3], [0, 5]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('control #1', [['...#~.', 'D.~~.D'], [1, 1], [1, 1]], [[0, 2], [0, 5], [1, 4]]),
('control #2', [['##.#.', '.~#D.', 'D#.~#'], [0, 3], [1, 4]], [[0, 4], [1, 0]])]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| regression reserved cells #1 | [[0, 1]] | [] | Failed |
| regression reserved cells #2 | [[2, 5], [3, 1], [3, 4], [5, 3], [5, 5]] | [[3, 1], [3, 4], [5, 5]] | Failed |
| partial repair boundary #1 | [[0, 0], [0, 3], [1, 2], [2, 5]] | [[0, 3], [1, 2], [2, 5]] | Failed |
| partial repair boundary #2 | [[1, 1], [1, 2]] | [[1, 1]] | Failed |
| door as neighbour #1 | [[1, 1]] | [[1, 1]] | Passed |
| chasm edge #1 | [[0, 0], [0, 2]] | [[0, 0], [0, 2]] | Passed |
| isolated floor #1 | [] | [] | Passed |
| control #1 | [[1, 0], [2, 4]] | [[1, 0], [2, 4]] | Passed |
SHA-256 / 61907a6a3d11249a87705a1e99ba71699f75ec64a6f637963e3e811ef3457065
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(grid, start, exit):
h = len(grid)
w = len(grid[0])
ends = []
for r in range(h):
for c in range(w):
if grid[r][c] != '.' or [r, c] in (start, exit):
continue
n = 0
for dr, dc in ((1, 0), (-1, 0), (0, 1), (0, -1)):
rr, cc = r + dr, c + dc
if 0 <= rr < h and 0 <= cc < w and grid[rr][cc] in '.D':
n += 1
if n == 1:
ends.append([r, c])
return ends
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression reserved cells #1', [['~.##.', 'D..#~', '...##'], [0, 3], [0, 1]], []),
('regression reserved cells #2',
[['#D...D', '#D#...', '##.##.', '#.##.#', '#D##.~', 'D.#...'], [2, 5], [5, 3]],
[[3, 1], [3, 4], [5, 5]]),
('partial repair boundary #1', [['..#...', '~..##.', '##~##.'], [0, 0], [0, 5]], [[0, 3], [1, 2], [2, 5]]),
('partial repair boundary #2', [['.##', '#..'], [1, 2], [0, 1]], [[1, 1]]),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('control #1', [['#.#.#', '.#D~~', '..~..', '..D.~'], [1, 4], [2, 0]], [[1, 0], [2, 4]])],
[('regression reserved cells #1', [['.#...~', '.#.D~D', '....##'], [1, 0], [0, 0]], [[0, 4]]),
('regression reserved cells #2', [['#.', '..', '##', '##', '##'], [0, 0], [1, 0]], [[0, 1]]),
('partial repair boundary #1', [['.##', '#..'], [1, 2], [0, 1]], [[1, 1]]),
('regression reserved cells #3',
[['#D...D', '#D#...', '##.##.', '#.##.#', '#D##.~', 'D.#...'], [2, 5], [5, 3]],
[[3, 1], [3, 4], [5, 5]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('control #1', [['#.#.#', '.#D~~', '..~..', '..D.~'], [1, 4], [2, 0]], [[1, 0], [2, 4]]),
('control #2', [['...D#~', '~.###~', '~..D..'], [1, 3], [0, 2]], [[0, 0], [2, 5]])],
[('regression reserved cells #1', [['#~.~.', '..#~.', '#.D.~', '~#~..'], [1, 4], [1, 0]], [[0, 4], [3, 4]]),
('regression reserved cells #2',
[['..#.D.', '~~D###', '...##.', '...DD~', 'D~.DD#', 'D..~D~'], [0, 4], [0, 0]],
[[0, 1], [0, 3], [0, 5]]),
('regression reserved cells #3', [['.#...~', '.#.D~D', '....##'], [1, 0], [0, 0]], [[0, 4]]),
('regression reserved cells #4', [['#.', '..', '##', '##', '##'], [0, 0], [1, 0]], [[0, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('control #1', [['...D#~', '~.###~', '~..D..'], [1, 3], [0, 2]], [[0, 0], [2, 5]]),
('control #2', [['#~.#.', '#...D', 'D.#..', '#....', '##..~'], [3, 0], [3, 3]], [[0, 2], [0, 4]])],
[('regression reserved cells #1', [['..', '.#'], [1, 1], [1, 0]], [[0, 1]]),
('regression reserved cells #2',
[['..~', '.~#', '#D~', '###', 'D.#', '.#~'], [1, 1], [5, 0]],
[[0, 1], [1, 0], [4, 1]]),
('regression reserved cells #3', [['#~.~.', '..#~.', '#.D.~', '~#~..'], [1, 4], [1, 0]], [[0, 4], [3, 4]]),
('partial repair boundary #1',
[['#.', '#.', '#.', '.#', '..', '~.'], [2, 1], [1, 0]],
[[0, 1], [3, 0], [5, 1]]),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('chasm edge #1', [['.~.', '...'], [1, 1], [1, 1]], [[0, 0], [0, 2]]),
('control #1', [['~D.#D', '#.#~.'], [0, 1], [1, 2]], [[0, 2], [1, 1], [1, 4]]),
('control #2', [['.~~##.', '##~DD~'], [0, 1], [1, 0]], [])],
[('regression reserved cells #1', [['~.#.~', '..#D.', '~##..'], [2, 4], [0, 3]], [[0, 1], [1, 0]]),
('regression reserved cells #2', [['D.DD', '~.##', '.###', '#.~.', '#DD~'], [2, 3], [3, 1]], [[1, 1]]),
('partial repair boundary #1', [['..~..D', '....#.'], [1, 5], [0, 2]], []),
('regression reserved cells #3',
[['..#.D.', '~~D###', '...##.', '...DD~', 'D~.DD#', 'D..~D~'], [0, 4], [0, 0]],
[[0, 1], [0, 3], [0, 5]]),
('isolated floor #1', [['#.#', '###'], [1, 0], [1, 0]], []),
('door as neighbour #1', [['#D#', '#.#', '###'], [0, 1], [0, 1]], [[1, 1]]),
('control #1', [['...#~.', 'D.~~.D'], [1, 1], [1, 1]], [[0, 2], [0, 5], [1, 4]]),
('control #2', [['##.#.', '.~#D.', 'D#.~#'], [0, 3], [1, 4]], [[0, 4], [1, 0]])]]
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| regression reserved cells #1 | [] | [] | Passed |
| regression reserved cells #2 | [[3, 1], [3, 4], [5, 5]] | [[3, 1], [3, 4], [5, 5]] | Passed |
| partial repair boundary #1 | [[0, 3], [1, 2], [2, 5]] | [[0, 3], [1, 2], [2, 5]] | Passed |
| partial repair boundary #2 | [[1, 1]] | [[1, 1]] | Passed |
| door as neighbour #1 | [[1, 1]] | [[1, 1]] | Passed |
| chasm edge #1 | [[0, 0], [0, 2]] | [[0, 0], [0, 2]] | Passed |
| isolated floor #1 | [] | [] | Passed |
| control #1 | [[1, 0], [2, 4]] | [[1, 0], [2, 4]] | Passed |
SHA-256 / 1e012e51c1c0fc1d8eddc1e82a31df9b5d36c6860d15d82057f4214f18c3d93f
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 2026-09-29T14:50:51.238470+00:00.
Case digest / 6aa2bfc8f8d2c89132e98d1732302956c35f6e6e3dc93d1869479d11e3ae2030