FAILURE MAP
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FA-70821 / GIS polygon topology / Open access

Missing node (T-junction) detection in a coverage: shared endpoint exclusion · case 01

Properly shared vertices are reported as T-junctions.

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

ROOT CAUSE

Vertices coinciding with an edge endpoint are not excluded.

THE FAILURE

Vertices coinciding with an edge endpoint are not excluded.

Unsuccessful approach: Only the edge start point is excluded, so the end point is still reported.

Case contract

Input: polygons as closed integer rings forming a coverage. For each polygon i and each distinct vertex v (closing duplicate excluded), and each other polygon j, report [i, v, j] when v lies exactly on an edge of j (zero cross product, inside the closed segment box) but is not one of that edge endpoints. Return the reports sorted.

Why this case matters

Coverage cleaning requires shared boundaries to have identical vertices; T-junctions cause gaps after simplification and must be noded first.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    polys = x
    out = []
    for i, P in enumerate(polys):
        for v in P[:-1]:
            for j, Q in enumerate(polys):
                if i == j:
                    continue
                for a, b in zip(Q, Q[1:]):
                    if False:
                        continue
                    cross = (b[0] - a[0]) * (v[1] - a[1]) - (b[1] - a[1]) * (v[0] - a[0])
                    if cross == 0 and min(a[0], b[0]) <= v[0] <= max(a[0], b[0]) and min(a[1], b[1]) <= v[1] <= max(a[1], b[1]):
                        out.append([i, list(v), j])
    return sorted(out)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('control #0', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]]], []), ('regression #1', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]]], [[1, [4, 2], 0]]), ('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #4', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[2, 4], [6, 4], [6, 8], [2, 8], [2, 4]]], [[0, [4, 4], 1], [1, [2, 4], 0]]), ('regression #5', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[10, 2], [14, 2], [14, 6], [10, 2]]], [[0, [12, 4], 1], [1, [10, 2], 0]]), ('regression #6', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[9, 1], [9, 6], [5, 6], [9, 1]]], [[1, [9, 1], 0]]), ('regression #7', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[6, 2], [9, 2], [9, 4], [6, 2]]], [[1, [6, 2], 0]])], [('regression #1', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]]], [[1, [4, 2], 0]]), ('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #5', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[10, 2], [14, 2], [14, 6], [10, 2]]], [[0, [12, 4], 1], [1, [10, 2], 0]]), ('regression #6', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[9, 1], [9, 6], [5, 6], [9, 1]]], [[1, [9, 1], 0]]), ('regression #7', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[6, 2], [9, 2], [9, 4], [6, 2]]], [[1, [6, 2], 0]]), ('regression #8', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[9, 2], [6, 2], [6, 4], [9, 2]]], [[1, [6, 2], 0], [1, [6, 4], 0]]), ('control #9', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[10, 10], [12, 10], [12, 12], [10, 12], [10, 10]]], []), ('regression #10', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[3, 4], [9, 1], [9, 9], [3, 4]]], [])], [('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #8', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[9, 2], [6, 2], [6, 4], [9, 2]]], [[1, [6, 2], 0], [1, [6, 4], 0]]), ('control #9', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[10, 10], [12, 10], [12, 12], [10, 12], [10, 10]]], []), ('regression #10', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[3, 4], [9, 1], [9, 9], [3, 4]]], []), ('regression #11', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[4, 4], [8, 0], [9, 9], [4, 4]]], [[0, [8, 8], 1], [1, [4, 4], 0]]), ('regression #12', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 1], [8, 1], [8, 3], [4, 3], [4, 1]]], [[1, [4, 1], 0], [1, [4, 3], 0]]), ('control #13', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[8, 0], [12, 0], [12, 4], [8, 4], [8, 0]]], [])], [('control #0', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]]], []), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #10', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[3, 4], [9, 1], [9, 9], [3, 4]]], []), ('regression #11', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[4, 4], [8, 0], [9, 9], [4, 4]]], [[0, [8, 8], 1], [1, [4, 4], 0]]), ('regression #12', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 1], [8, 1], [8, 3], [4, 3], [4, 1]]], [[1, [4, 1], 0], [1, [4, 3], 0]]), ('control #13', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[8, 0], [12, 0], [12, 4], [8, 4], [8, 0]]], []), ('regression #14', [[[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]]], [[1, [2, 4], 0], [1, [6, 4], 0]]), ('regression #15', [[[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]], [[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[0, 8], [8, 8], [8, 12], [0, 12], [0, 8]]], [[0, [2, 4], 1], [0, [2, 8], 2], [0, [6, 4], 1], [0, [6, 8], 2]])], [('control #0', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]]], []), ('regression #1', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]]], [[1, [4, 2], 0]]), ('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #4', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[2, 4], [6, 4], [6, 8], [2, 8], [2, 4]]], [[0, [4, 4], 1], [1, [2, 4], 0]]), ('control #13', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[8, 0], [12, 0], [12, 4], [8, 4], [8, 0]]], []), ('regression #14', [[[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]]], [[1, [2, 4], 0], [1, [6, 4], 0]]), ('regression #15', [[[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]], [[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[0, 8], [8, 8], [8, 12], [0, 12], [0, 8]]], [[0, [2, 4], 1], [0, [2, 8], 2], [0, [6, 4], 1], [0, [6, 8], 2]])]]
for label, args, expected in fixtures[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
control #0[[0, [4, 0], 1], [0, [4, 0], 1], [0, [4, 4], 1], [0, [4, 4], 1], [1, [4, 0], 0], [1, [4, 0], 0], [1, [4, 4], 0], [1, [4, 4], 0]][]Failed
regression #1[[0, [4, 0], 1], [0, [4, 0], 1], [0, [4, 4], 1], [0, [4, 4], 1], [1, [4, 0], 0], [1, [4, 0], 0], [1, [4, 2], 0], [1, [4, 4], 0], [1, [4, 4], 0]][[1, [4, 2], 0]]Failed
regression #2[[0, [4, 0], 1], [0, [4, 0], 1], [0, [4, 2], 1], [0, [4, 4], 1], [0, [4, 4], 1], [1, [4, 0], 0], [1, [4, 0], 0], [1, [4, 4], 0], [1, [4, 4], 0]][[0, [4, 2], 1]]Failed
regression #3[[0, [0, 4], 2], [0, [0, 4], 2], [0, [4, 0], 1], [0, [4, 0], 1], [0, [4, 4], 1], [0, [4, 4], 1], [0, [4, 4], 2], [0, [4, 4], 2], [1, [4, 0], 0], [1, [4, 0], 0], [1, [4, 4], 0], [1, [4, 4], 0], [1, [4, 4], 2], [1, [4, 4], 2], [2, [0, 4], 0], [2, [0, 4], 0], [2, [4, 4], 0], [2, [4, 4], 0], [2, [4, 4], 1], [2, [4, 4], 1]][]Failed
regression #4[[0, [4, 4], 1], [1, [2, 4], 0]][[0, [4, 4], 1], [1, [2, 4], 0]]Passed
regression #5[[0, [12, 4], 1], [1, [10, 2], 0]][[0, [12, 4], 1], [1, [10, 2], 0]]Passed
regression #6[[1, [9, 1], 0]][[1, [9, 1], 0]]Passed
regression #7[[1, [6, 2], 0]][[1, [6, 2], 0]]Passed

SHA-256 / fd81191ae70624a56e4c6af91d19b17b14ffb1756a41e8be31383d65b0cc5928

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    polys = x
    out = []
    for i, P in enumerate(polys):
        for v in P[:-1]:
            for j, Q in enumerate(polys):
                if i == j:
                    continue
                for a, b in zip(Q, Q[1:]):
                    if v == a:
                        continue
                    cross = (b[0] - a[0]) * (v[1] - a[1]) - (b[1] - a[1]) * (v[0] - a[0])
                    if cross == 0 and min(a[0], b[0]) <= v[0] <= max(a[0], b[0]) and min(a[1], b[1]) <= v[1] <= max(a[1], b[1]):
                        out.append([i, list(v), j])
    return sorted(out)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('control #0', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]]], []), ('regression #1', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]]], [[1, [4, 2], 0]]), ('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #4', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[2, 4], [6, 4], [6, 8], [2, 8], [2, 4]]], [[0, [4, 4], 1], [1, [2, 4], 0]]), ('regression #5', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[10, 2], [14, 2], [14, 6], [10, 2]]], [[0, [12, 4], 1], [1, [10, 2], 0]]), ('regression #6', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[9, 1], [9, 6], [5, 6], [9, 1]]], [[1, [9, 1], 0]]), ('regression #7', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[6, 2], [9, 2], [9, 4], [6, 2]]], [[1, [6, 2], 0]])], [('regression #1', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]]], [[1, [4, 2], 0]]), ('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #5', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[10, 2], [14, 2], [14, 6], [10, 2]]], [[0, [12, 4], 1], [1, [10, 2], 0]]), ('regression #6', [[[8, 0], [12, 4], [8, 4], [8, 0]], [[9, 1], [9, 6], [5, 6], [9, 1]]], [[1, [9, 1], 0]]), ('regression #7', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[6, 2], [9, 2], [9, 4], [6, 2]]], [[1, [6, 2], 0]]), ('regression #8', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[9, 2], [6, 2], [6, 4], [9, 2]]], [[1, [6, 2], 0], [1, [6, 4], 0]]), ('control #9', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[10, 10], [12, 10], [12, 12], [10, 12], [10, 10]]], []), ('regression #10', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[3, 4], [9, 1], [9, 9], [3, 4]]], [])], [('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #8', [[[0, 0], [6, 0], [6, 6], [0, 6], [0, 0]], [[9, 2], [6, 2], [6, 4], [9, 2]]], [[1, [6, 2], 0], [1, [6, 4], 0]]), ('control #9', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[10, 10], [12, 10], [12, 12], [10, 12], [10, 10]]], []), ('regression #10', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[3, 4], [9, 1], [9, 9], [3, 4]]], []), ('regression #11', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[4, 4], [8, 0], [9, 9], [4, 4]]], [[0, [8, 8], 1], [1, [4, 4], 0]]), ('regression #12', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 1], [8, 1], [8, 3], [4, 3], [4, 1]]], [[1, [4, 1], 0], [1, [4, 3], 0]]), ('control #13', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[8, 0], [12, 0], [12, 4], [8, 4], [8, 0]]], [])], [('control #0', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]]], []), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #10', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[3, 4], [9, 1], [9, 9], [3, 4]]], []), ('regression #11', [[[0, 0], [8, 8], [0, 8], [0, 0]], [[4, 4], [8, 0], [9, 9], [4, 4]]], [[0, [8, 8], 1], [1, [4, 4], 0]]), ('regression #12', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 1], [8, 1], [8, 3], [4, 3], [4, 1]]], [[1, [4, 1], 0], [1, [4, 3], 0]]), ('control #13', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[8, 0], [12, 0], [12, 4], [8, 4], [8, 0]]], []), ('regression #14', [[[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]]], [[1, [2, 4], 0], [1, [6, 4], 0]]), ('regression #15', [[[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]], [[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[0, 8], [8, 8], [8, 12], [0, 12], [0, 8]]], [[0, [2, 4], 1], [0, [2, 8], 2], [0, [6, 4], 1], [0, [6, 8], 2]])], [('control #0', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]]], []), ('regression #1', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]]], [[1, [4, 2], 0]]), ('regression #2', [[[4, 0], [8, 0], [8, 4], [4, 4], [4, 2], [4, 0]], [[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]]], [[0, [4, 2], 1]]), ('regression #3', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[0, 4], [4, 4], [4, 8], [0, 8], [0, 4]]], []), ('regression #4', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[2, 4], [6, 4], [6, 8], [2, 8], [2, 4]]], [[0, [4, 4], 1], [1, [2, 4], 0]]), ('control #13', [[[0, 0], [4, 0], [4, 4], [0, 4], [0, 0]], [[4, 0], [8, 0], [8, 4], [4, 4], [4, 0]], [[8, 0], [12, 0], [12, 4], [8, 4], [8, 0]]], []), ('regression #14', [[[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]]], [[1, [2, 4], 0], [1, [6, 4], 0]]), ('regression #15', [[[6, 4], [6, 8], [2, 8], [2, 4], [6, 4]], [[0, 0], [8, 0], [8, 4], [0, 4], [0, 0]], [[0, 8], [8, 8], [8, 12], [0, 12], [0, 8]]], [[0, [2, 4], 1], [0, [2, 8], 2], [0, [6, 4], 1], [0, [6, 8], 2]])]]
for label, args, expected in fixtures[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
control #0[[0, [4, 0], 1], [0, [4, 4], 1], [1, [4, 0], 0], [1, [4, 4], 0]][]Failed
regression #1[[0, [4, 0], 1], [0, [4, 4], 1], [1, [4, 0], 0], [1, [4, 2], 0], [1, [4, 4], 0]][[1, [4, 2], 0]]Failed
regression #2[[0, [4, 0], 1], [0, [4, 2], 1], [0, [4, 4], 1], [1, [4, 0], 0], [1, [4, 4], 0]][[0, [4, 2], 1]]Failed
regression #3[[0, [0, 4], 2], [0, [4, 0], 1], [0, [4, 4], 1], [0, [4, 4], 2], [1, [4, 0], 0], [1, [4, 4], 0], [1, [4, 4], 2], [2, [0, 4], 0], [2, [4, 4], 0], [2, [4, 4], 1]][]Failed
regression #4[[0, [4, 4], 1], [1, [2, 4], 0]][[0, [4, 4], 1], [1, [2, 4], 0]]Passed
regression #5[[0, [12, 4], 1], [1, [10, 2], 0]][[0, [12, 4], 1], [1, [10, 2], 0]]Passed
regression #6[[1, [9, 1], 0]][[1, [9, 1], 0]]Passed
regression #7[[1, [6, 2], 0]][[1, [6, 2], 0]]Passed

SHA-256 / 61373cb85c2bb67d2bd05ad4f7015d5795ba053c9349a30d525624181a2ce21f

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

Stipulated deterministic toy contract on a bounded input domain; results are rounded as stated and no conformance with any published standard or library is claimed. 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 2026-09-29T14:48:24.211398+00:00.

Case digest / 7ecc38801c41e335ae70d053a225a948bf3140931a4a59a6f39a62831c58d7ff