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FA-86181 / Game economy crafting balance / Open access

Inventory stack insertion: Top-up fills later slots first · case 01

Loot lands in the last partial stack instead of the first.

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

ROOT CAUSE

Partial stacks are topped up from the end of the bag.

VERIFIED REPAIR

Restore `for s in slots:` at the top-up order step.

Unsuccessful approach: Filling fullest stacks first still ignores slot order.

Case contract

slots = list of None or [name, count]; names are case sensitive. First top up partial stacks (count < max_stack) of the same item in slot order, then fill empty slots in order with new stacks of at most max_stack. Reserved placeholders [name, 0] count as partial stacks. Legacy stacks above max_stack are left untouched. Returns {slots, leftover}.

Why this case matters

Game economies leak or destroy currency when one crafting or pricing rule is off by one boundary, rounding stage or state update; the defect is observable in exact integer outcomes.

1 / The failure

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

N = 1
observations = []
def solve(slots, item, qty, max_stack):
    slots = [s if s is None else list(s) for s in slots]
    left = qty
    for s in reversed(slots):
        if left == 0:
            break
        if s is not None and s[0] == item and s[1] < max_stack:
            add = min(left, max_stack - s[1])
            s[1] += add
            left -= add
    for i in range(len(slots)):
        if left == 0:
            break
        if slots[i] is None:
            add = min(left, max_stack)
            slots[i] = [item, add]
            left -= add
    return {'slots': slots, 'leftover': left}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 19], ['Arrow', 15]], 'Arrow', 1, 20],
   {'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 1]], 'Potion', 1, 20],
   {'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 1]], 'Potion', 1, 20],
   {'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['Potion', 8], ['Potion', 20], ['arrow', 1], ['Potion', 0], ['arrow', 20], None], 'Potion', 7, 10],
   {'slots': [['Potion', 10], ['Potion', 20], ['arrow', 1], ['Potion', 5], ['arrow', 20], None],
    'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[['arrow', 25], ['arrow', 4], ['Arrow', 0], ['arrow', 0], ['arrow', 25]], 'arrow', 1, 10],
   {'slots': [['arrow', 25], ['arrow', 5], ['Arrow', 0], ['arrow', 0], ['arrow', 25]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['Potion', 0], ['Arrow', 1], ['Arrow', 0]], 'Arrow', 7, 20],
   {'slots': [['Potion', 0], ['Arrow', 8], ['Arrow', 0]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[['Arrow', 19], ['Arrow', 5]], 'Arrow', 7, 20],
   {'slots': [['Arrow', 20], ['Arrow', 11]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['arrow', 3], None, ['arrow', 0]], 'arrow', 1, 10],
   {'slots': [['arrow', 4], None, ['arrow', 0]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[None, ['Arrow', 16], ['arrow', 20], None, ['Arrow', 25], None], 'Potion', 20, 10],
   {'slots': [['Potion', 10], ['Arrow', 16], ['arrow', 20], ['Potion', 10], ['Arrow', 25], None],
    'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1', [[None], 'Arrow', 11, 20], {'slots': [['Arrow', 11]], 'leftover': 0}),
  ('control #2', [[['Potion', 20]], 'Arrow', 0, 20], {'slots': [['Potion', 20]], 'leftover': 0}),
  ('control #3', [[], 'arrow', 45, 5], {'slots': [], 'leftover': 45})]]
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
two partial stacks #1{'leftover': 0, 'slots': [['Arrow', 18], ['Arrow', 19], None]}{'leftover': 0, 'slots': [['Arrow', 20], ['Arrow', 17], None]}Failed
fault site top-up order #1{'leftover': 0, 'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 19], ['Arrow', 16]]}{'leftover': 0, 'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]]}Failed
fault site top-up order #2{'leftover': 0, 'slots': [None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 2]]}{'leftover': 0, 'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]]}Failed
regression top-up order #1{'leftover': 0, 'slots': [['arrow', 6], ['arrow', 20]]}{'leftover': 0, 'slots': [['arrow', 7], ['arrow', 19]]}Failed
regression top-up order #2{'leftover': 0, 'slots': [['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 20]]}{'leftover': 0, 'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]]}Failed
legacy overfull stack #1{'leftover': 0, 'slots': [['Arrow', 25], ['Arrow', 3]]}{'leftover': 0, 'slots': [['Arrow', 25], ['Arrow', 3]]}Passed
case distinct item #1{'leftover': 2, 'slots': [['arrow', 3]]}{'leftover': 2, 'slots': [['arrow', 3]]}Passed
control #1{'leftover': 0, 'slots': [['Arrow', 6], None, ['arrow', 5]]}{'leftover': 0, 'slots': [['Arrow', 6], None, ['arrow', 5]]}Passed

SHA-256 / 11a0395fdf97ede3a36cd5d768e6c764c465da292854f3712071d66ee62d8940

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(slots, item, qty, max_stack):
    slots = [s if s is None else list(s) for s in slots]
    left = qty
    for s in sorted((s for s in slots if s), key=lambda s: -s[1]):
        if left == 0:
            break
        if s is not None and s[0] == item and s[1] < max_stack:
            add = min(left, max_stack - s[1])
            s[1] += add
            left -= add
    for i in range(len(slots)):
        if left == 0:
            break
        if slots[i] is None:
            add = min(left, max_stack)
            slots[i] = [item, add]
            left -= add
    return {'slots': slots, 'leftover': left}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 19], ['Arrow', 15]], 'Arrow', 1, 20],
   {'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 1]], 'Potion', 1, 20],
   {'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 1]], 'Potion', 1, 20],
   {'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['Potion', 8], ['Potion', 20], ['arrow', 1], ['Potion', 0], ['arrow', 20], None], 'Potion', 7, 10],
   {'slots': [['Potion', 10], ['Potion', 20], ['arrow', 1], ['Potion', 5], ['arrow', 20], None],
    'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[['arrow', 25], ['arrow', 4], ['Arrow', 0], ['arrow', 0], ['arrow', 25]], 'arrow', 1, 10],
   {'slots': [['arrow', 25], ['arrow', 5], ['Arrow', 0], ['arrow', 0], ['arrow', 25]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['Potion', 0], ['Arrow', 1], ['Arrow', 0]], 'Arrow', 7, 20],
   {'slots': [['Potion', 0], ['Arrow', 8], ['Arrow', 0]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[['Arrow', 19], ['Arrow', 5]], 'Arrow', 7, 20],
   {'slots': [['Arrow', 20], ['Arrow', 11]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['arrow', 3], None, ['arrow', 0]], 'arrow', 1, 10],
   {'slots': [['arrow', 4], None, ['arrow', 0]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[None, ['Arrow', 16], ['arrow', 20], None, ['Arrow', 25], None], 'Potion', 20, 10],
   {'slots': [['Potion', 10], ['Arrow', 16], ['arrow', 20], ['Potion', 10], ['Arrow', 25], None],
    'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1', [[None], 'Arrow', 11, 20], {'slots': [['Arrow', 11]], 'leftover': 0}),
  ('control #2', [[['Potion', 20]], 'Arrow', 0, 20], {'slots': [['Potion', 20]], 'leftover': 0}),
  ('control #3', [[], 'arrow', 45, 5], {'slots': [], 'leftover': 45})]]
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
two partial stacks #1{'leftover': 0, 'slots': [['Arrow', 20], ['Arrow', 17], None]}{'leftover': 0, 'slots': [['Arrow', 20], ['Arrow', 17], None]}Passed
fault site top-up order #1{'leftover': 0, 'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]]}{'leftover': 0, 'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]]}Passed
fault site top-up order #2{'leftover': 0, 'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]]}{'leftover': 0, 'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]]}Passed
regression top-up order #1{'leftover': 0, 'slots': [['arrow', 6], ['arrow', 20]]}{'leftover': 0, 'slots': [['arrow', 7], ['arrow', 19]]}Failed
regression top-up order #2{'leftover': 0, 'slots': [['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 20]]}{'leftover': 0, 'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]]}Failed
legacy overfull stack #1{'leftover': 0, 'slots': [['Arrow', 25], ['Arrow', 3]]}{'leftover': 0, 'slots': [['Arrow', 25], ['Arrow', 3]]}Passed
case distinct item #1{'leftover': 2, 'slots': [['arrow', 3]]}{'leftover': 2, 'slots': [['arrow', 3]]}Passed
control #1{'leftover': 0, 'slots': [['Arrow', 6], None, ['arrow', 5]]}{'leftover': 0, 'slots': [['Arrow', 6], None, ['arrow', 5]]}Passed

SHA-256 / a951a8fd627bd6c7618fd0028d513f7aa7194ee91e3929ad6fd94026d0f36e0b

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(slots, item, qty, max_stack):
    slots = [s if s is None else list(s) for s in slots]
    left = qty
    for s in slots:
        if left == 0:
            break
        if s is not None and s[0] == item and s[1] < max_stack:
            add = min(left, max_stack - s[1])
            s[1] += add
            left -= add
    for i in range(len(slots)):
        if left == 0:
            break
        if slots[i] is None:
            add = min(left, max_stack)
            slots[i] = [item, add]
            left -= add
    return {'slots': slots, 'leftover': left}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 19], ['Arrow', 15]], 'Arrow', 1, 20],
   {'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 1]], 'Potion', 1, 20],
   {'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[None, ['Arrow', 0], ['Potion', 19], None, ['Arrow', 14], ['Potion', 1]], 'Potion', 1, 20],
   {'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['Potion', 8], ['Potion', 20], ['arrow', 1], ['Potion', 0], ['arrow', 20], None], 'Potion', 7, 10],
   {'slots': [['Potion', 10], ['Potion', 20], ['arrow', 1], ['Potion', 5], ['arrow', 20], None],
    'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[['arrow', 25], ['arrow', 4], ['Arrow', 0], ['arrow', 0], ['arrow', 25]], 'arrow', 1, 10],
   {'slots': [['arrow', 25], ['arrow', 5], ['Arrow', 0], ['arrow', 0], ['arrow', 25]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['Potion', 0], ['Arrow', 1], ['Arrow', 0]], 'Arrow', 7, 20],
   {'slots': [['Potion', 0], ['Arrow', 8], ['Arrow', 0]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[['Arrow', 6], None, ['arrow', 5]], 'Potion', 0, 20],
   {'slots': [['Arrow', 6], None, ['arrow', 5]], 'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('fault site top-up order #1',
   [[['Arrow', 19], ['Arrow', 5]], 'Arrow', 7, 20],
   {'slots': [['Arrow', 20], ['Arrow', 11]], 'leftover': 0}),
  ('fault site top-up order #2',
   [[['arrow', 3], None, ['arrow', 0]], 'arrow', 1, 10],
   {'slots': [['arrow', 4], None, ['arrow', 0]], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1',
   [[None, ['Arrow', 16], ['arrow', 20], None, ['Arrow', 25], None], 'Potion', 20, 10],
   {'slots': [['Potion', 10], ['Arrow', 16], ['arrow', 20], ['Potion', 10], ['Arrow', 25], None],
    'leftover': 0})],
 [('two partial stacks #1',
   [[['Arrow', 18], ['Arrow', 15], None], 'Arrow', 4, 20],
   {'slots': [['Arrow', 20], ['Arrow', 17], None], 'leftover': 0}),
  ('regression top-up order #1',
   [[['arrow', 0], ['arrow', 19]], 'arrow', 7, 20],
   {'slots': [['arrow', 7], ['arrow', 19]], 'leftover': 0}),
  ('regression top-up order #2',
   [[['Arrow', 5], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'Arrow', 1, 20],
   {'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]], 'leftover': 0}),
  ('legacy overfull stack #1',
   [[['Arrow', 25], None], 'Arrow', 3, 20],
   {'slots': [['Arrow', 25], ['Arrow', 3]], 'leftover': 0}),
  ('case distinct item #1', [[['arrow', 3]], 'Arrow', 2, 20], {'slots': [['arrow', 3]], 'leftover': 2}),
  ('control #1', [[None], 'Arrow', 11, 20], {'slots': [['Arrow', 11]], 'leftover': 0}),
  ('control #2', [[['Potion', 20]], 'Arrow', 0, 20], {'slots': [['Potion', 20]], 'leftover': 0}),
  ('control #3', [[], 'arrow', 45, 5], {'slots': [], 'leftover': 45})]]
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
two partial stacks #1{'leftover': 0, 'slots': [['Arrow', 20], ['Arrow', 17], None]}{'leftover': 0, 'slots': [['Arrow', 20], ['Arrow', 17], None]}Passed
fault site top-up order #1{'leftover': 0, 'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]]}{'leftover': 0, 'slots': [None, ['Potion', 1], ['Potion', 25], None, ['Arrow', 20], ['Arrow', 15]]}Passed
fault site top-up order #2{'leftover': 0, 'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]]}{'leftover': 0, 'slots': [None, ['Arrow', 0], ['Potion', 20], None, ['Arrow', 14], ['Potion', 1]]}Passed
regression top-up order #1{'leftover': 0, 'slots': [['arrow', 7], ['arrow', 19]]}{'leftover': 0, 'slots': [['arrow', 7], ['arrow', 19]]}Passed
regression top-up order #2{'leftover': 0, 'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]]}{'leftover': 0, 'slots': [['Arrow', 6], ['arrow', 1], ['arrow', 25], None, ['Arrow', 19]]}Passed
legacy overfull stack #1{'leftover': 0, 'slots': [['Arrow', 25], ['Arrow', 3]]}{'leftover': 0, 'slots': [['Arrow', 25], ['Arrow', 3]]}Passed
case distinct item #1{'leftover': 2, 'slots': [['arrow', 3]]}{'leftover': 2, 'slots': [['arrow', 3]]}Passed
control #1{'leftover': 0, 'slots': [['Arrow', 6], None, ['arrow', 5]]}{'leftover': 0, 'slots': [['Arrow', 6], None, ['arrow', 5]]}Passed

SHA-256 / 53d7b872ff7d41bff60a44161cc92305257ee63bb9fd39f0ff8aee4e0dc11d34

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 2026-09-29T14:50:47.286967+00:00.

Case digest / 4facc7f882a0a71c276b5c6aa8f982bb37eb152a8af7acdbd0300c0264da5d32