FA-97436 / Knitting and sewing pattern grading / Open access

Pattern row locator: setup boundary · case 01

The last setup row is reported as repeat 0.

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

ROOT CAUSE

The setup test excludes its final row.

VERIFIED REPAIR

Rows up to and including setup are setup rows.

Unsuccessful approach: Excluding single-row setups still misplaces row 1.

Case contract

Rows are 1-based. Rows 1..setup are ["setup", row]. The next length*repeats rows are ["repeat", repeat_number, row_in_repeat] (both 1-based). Later rows are ["finishing", k] counting from 1 after the last repeat. row < 1 -> "error: rows start at 1".

Why this case matters

Row counter apps must map an absolute row number onto setup, repeat and finishing sections.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(row, setup, length, repeats):
    if row < 1:
        return 'error: rows start at 1'
    if row < setup:
        return ['setup', row]
    k = row - setup
    if k <= length * repeats:
        return ['repeat', (k - 1) // length + 1, (k - 1) % length + 1]
    return ['finishing', k - length * repeats]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['last setup row', [4, 4, 8, 3], ['setup', 4]], ['first repeat row', [5, 4, 8, 3], ['repeat', 1, 1]],
  ['single setup row', [1, 1, 4, 2], ['setup', 1]],
  ['regression: setup boundary', [4, 4, 1, 1], ['setup', 4]],
  ['generated control 1', [19, 6, 8, 3], ['repeat', 2, 5]],
  ['generated control 2', [11, 6, 8, 3], ['repeat', 1, 5]],
  ['generated control 3', [0, 4, 1, 5], 'error: rows start at 1'],
  ['generated control 4', [8, 4, 4, 2], ['repeat', 1, 4]]],
 [['first repeat row', [5, 4, 8, 3], ['repeat', 1, 1]], ['single setup row', [1, 1, 4, 2], ['setup', 1]],
  ['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['regression: setup boundary', [2, 2, 4, 2], ['setup', 2]],
  ['repair check: setup boundary', [1, 1, 4, 1], ['setup', 1]],
  ['generated control 1', [56, 0, 8, 3], ['finishing', 32]],
  ['generated control 2', [28, 2, 1, 5], ['finishing', 21]],
  ['generated control 3', [49, 4, 12, 5], ['repeat', 4, 9]]],
 [['single setup row', [1, 1, 4, 2], ['setup', 1]], ['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['regression: setup boundary', [4, 4, 6, 1], ['setup', 4]],
  ['repair check: setup boundary', [1, 1, 6, 5], ['setup', 1]],
  ['generated control 1', [56, 1, 12, 3], ['finishing', 19]],
  ['generated control 2', [57, 6, 1, 1], ['finishing', 50]],
  ['generated control 3', [10, 0, 8, 3], ['repeat', 2, 2]]],
 [['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['row zero', [0, 2, 4, 2], 'error: rows start at 1'],
  ['regression: setup boundary', [6, 6, 8, 1], ['setup', 6]],
  ['repair check: setup boundary', [1, 1, 4, 3], ['setup', 1]],
  ['generated control 1', [16, 1, 1, 5], ['finishing', 10]],
  ['generated control 2', [15, 4, 1, 3], ['finishing', 8]],
  ['generated control 3', [30, 0, 8, 5], ['repeat', 4, 6]]],
 [['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['row zero', [0, 2, 4, 2], 'error: rows start at 1'], ['last setup row', [4, 4, 8, 3], ['setup', 4]],
  ['regression: setup boundary', [4, 4, 1, 3], ['setup', 4]],
  ['repair check: setup boundary', [1, 1, 1, 1], ['setup', 1]],
  ['generated control 1', [36, 6, 12, 2], ['finishing', 6]],
  ['generated control 2', [11, 1, 8, 2], ['repeat', 2, 2]],
  ['generated control 3', [55, 1, 12, 5], ['repeat', 5, 6]]]]
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 fixture	Actual	Expected	Outcome
last setup row	`['repeat', 0, 8]`	`['setup', 4]`	Failed
first repeat row	`['repeat', 1, 1]`	`['repeat', 1, 1]`	Passed
single setup row	`['repeat', 0, 4]`	`['setup', 1]`	Failed
regression: setup boundary	`['repeat', 0, 1]`	`['setup', 4]`	Failed
generated control 1	`['repeat', 2, 5]`	`['repeat', 2, 5]`	Passed
generated control 2	`['repeat', 1, 5]`	`['repeat', 1, 5]`	Passed
generated control 3	`error: rows start at 1`	`error: rows start at 1`	Passed
generated control 4	`['repeat', 1, 4]`	`['repeat', 1, 4]`	Passed

SHA-256 / ad502e7498482635ce86360df9aa22a6e63d7cd596720dfe5754f20ff86a6d1e

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(row, setup, length, repeats):
    if row < 1:
        return 'error: rows start at 1'
    if row <= setup and setup > 1:
        return ['setup', row]
    k = row - setup
    if k <= length * repeats:
        return ['repeat', (k - 1) // length + 1, (k - 1) % length + 1]
    return ['finishing', k - length * repeats]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['last setup row', [4, 4, 8, 3], ['setup', 4]], ['first repeat row', [5, 4, 8, 3], ['repeat', 1, 1]],
  ['single setup row', [1, 1, 4, 2], ['setup', 1]],
  ['regression: setup boundary', [4, 4, 1, 1], ['setup', 4]],
  ['generated control 1', [19, 6, 8, 3], ['repeat', 2, 5]],
  ['generated control 2', [11, 6, 8, 3], ['repeat', 1, 5]],
  ['generated control 3', [0, 4, 1, 5], 'error: rows start at 1'],
  ['generated control 4', [8, 4, 4, 2], ['repeat', 1, 4]]],
 [['first repeat row', [5, 4, 8, 3], ['repeat', 1, 1]], ['single setup row', [1, 1, 4, 2], ['setup', 1]],
  ['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['regression: setup boundary', [2, 2, 4, 2], ['setup', 2]],
  ['repair check: setup boundary', [1, 1, 4, 1], ['setup', 1]],
  ['generated control 1', [56, 0, 8, 3], ['finishing', 32]],
  ['generated control 2', [28, 2, 1, 5], ['finishing', 21]],
  ['generated control 3', [49, 4, 12, 5], ['repeat', 4, 9]]],
 [['single setup row', [1, 1, 4, 2], ['setup', 1]], ['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['regression: setup boundary', [4, 4, 6, 1], ['setup', 4]],
  ['repair check: setup boundary', [1, 1, 6, 5], ['setup', 1]],
  ['generated control 1', [56, 1, 12, 3], ['finishing', 19]],
  ['generated control 2', [57, 6, 1, 1], ['finishing', 50]],
  ['generated control 3', [10, 0, 8, 3], ['repeat', 2, 2]]],
 [['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['row zero', [0, 2, 4, 2], 'error: rows start at 1'],
  ['regression: setup boundary', [6, 6, 8, 1], ['setup', 6]],
  ['repair check: setup boundary', [1, 1, 4, 3], ['setup', 1]],
  ['generated control 1', [16, 1, 1, 5], ['finishing', 10]],
  ['generated control 2', [15, 4, 1, 3], ['finishing', 8]],
  ['generated control 3', [30, 0, 8, 5], ['repeat', 4, 6]]],
 [['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['row zero', [0, 2, 4, 2], 'error: rows start at 1'], ['last setup row', [4, 4, 8, 3], ['setup', 4]],
  ['regression: setup boundary', [4, 4, 1, 3], ['setup', 4]],
  ['repair check: setup boundary', [1, 1, 1, 1], ['setup', 1]],
  ['generated control 1', [36, 6, 12, 2], ['finishing', 6]],
  ['generated control 2', [11, 1, 8, 2], ['repeat', 2, 2]],
  ['generated control 3', [55, 1, 12, 5], ['repeat', 5, 6]]]]
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 fixture	Actual	Expected	Outcome
last setup row	`['setup', 4]`	`['setup', 4]`	Passed
first repeat row	`['repeat', 1, 1]`	`['repeat', 1, 1]`	Passed
single setup row	`['repeat', 0, 4]`	`['setup', 1]`	Failed
regression: setup boundary	`['setup', 4]`	`['setup', 4]`	Passed
generated control 1	`['repeat', 2, 5]`	`['repeat', 2, 5]`	Passed
generated control 2	`['repeat', 1, 5]`	`['repeat', 1, 5]`	Passed
generated control 3	`error: rows start at 1`	`error: rows start at 1`	Passed
generated control 4	`['repeat', 1, 4]`	`['repeat', 1, 4]`	Passed

SHA-256 / 775ff13fbc7ade16a6fb1ff051835042d98e28250965c8a597f95e95a6d82bf9

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(row, setup, length, repeats):
    if row < 1:
        return 'error: rows start at 1'
    if row <= setup:
        return ['setup', row]
    k = row - setup
    if k <= length * repeats:
        return ['repeat', (k - 1) // length + 1, (k - 1) % length + 1]
    return ['finishing', k - length * repeats]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['last setup row', [4, 4, 8, 3], ['setup', 4]], ['first repeat row', [5, 4, 8, 3], ['repeat', 1, 1]],
  ['single setup row', [1, 1, 4, 2], ['setup', 1]],
  ['regression: setup boundary', [4, 4, 1, 1], ['setup', 4]],
  ['generated control 1', [19, 6, 8, 3], ['repeat', 2, 5]],
  ['generated control 2', [11, 6, 8, 3], ['repeat', 1, 5]],
  ['generated control 3', [0, 4, 1, 5], 'error: rows start at 1'],
  ['generated control 4', [8, 4, 4, 2], ['repeat', 1, 4]]],
 [['first repeat row', [5, 4, 8, 3], ['repeat', 1, 1]], ['single setup row', [1, 1, 4, 2], ['setup', 1]],
  ['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['regression: setup boundary', [2, 2, 4, 2], ['setup', 2]],
  ['repair check: setup boundary', [1, 1, 4, 1], ['setup', 1]],
  ['generated control 1', [56, 0, 8, 3], ['finishing', 32]],
  ['generated control 2', [28, 2, 1, 5], ['finishing', 21]],
  ['generated control 3', [49, 4, 12, 5], ['repeat', 4, 9]]],
 [['single setup row', [1, 1, 4, 2], ['setup', 1]], ['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['regression: setup boundary', [4, 4, 6, 1], ['setup', 4]],
  ['repair check: setup boundary', [1, 1, 6, 5], ['setup', 1]],
  ['generated control 1', [56, 1, 12, 3], ['finishing', 19]],
  ['generated control 2', [57, 6, 1, 1], ['finishing', 50]],
  ['generated control 3', [10, 0, 8, 3], ['repeat', 2, 2]]],
 [['last row of repeat', [12, 4, 8, 3], ['repeat', 1, 8]],
  ['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['row zero', [0, 2, 4, 2], 'error: rows start at 1'],
  ['regression: setup boundary', [6, 6, 8, 1], ['setup', 6]],
  ['repair check: setup boundary', [1, 1, 4, 3], ['setup', 1]],
  ['generated control 1', [16, 1, 1, 5], ['finishing', 10]],
  ['generated control 2', [15, 4, 1, 3], ['finishing', 8]],
  ['generated control 3', [30, 0, 8, 5], ['repeat', 4, 6]]],
 [['first finishing row', [29, 4, 8, 3], ['finishing', 1]],
  ['row zero', [0, 2, 4, 2], 'error: rows start at 1'], ['last setup row', [4, 4, 8, 3], ['setup', 4]],
  ['regression: setup boundary', [4, 4, 1, 3], ['setup', 4]],
  ['repair check: setup boundary', [1, 1, 1, 1], ['setup', 1]],
  ['generated control 1', [36, 6, 12, 2], ['finishing', 6]],
  ['generated control 2', [11, 1, 8, 2], ['repeat', 2, 2]],
  ['generated control 3', [55, 1, 12, 5], ['repeat', 5, 6]]]]
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 fixture	Actual	Expected	Outcome
last setup row	`['setup', 4]`	`['setup', 4]`	Passed
first repeat row	`['repeat', 1, 1]`	`['repeat', 1, 1]`	Passed
single setup row	`['setup', 1]`	`['setup', 1]`	Passed
regression: setup boundary	`['setup', 4]`	`['setup', 4]`	Passed
generated control 1	`['repeat', 2, 5]`	`['repeat', 2, 5]`	Passed
generated control 2	`['repeat', 1, 5]`	`['repeat', 1, 5]`	Passed
generated control 3	`error: rows start at 1`	`error: rows start at 1`	Passed
generated control 4	`['repeat', 1, 4]`	`['repeat', 1, 4]`	Passed

SHA-256 / a437231f0b35f1b1156a2529993970c86be8a90405a7b0c2098bc80e619abd9f

Verification & scope

A deterministic toy contract stated in full here; it is a bounded teaching model, not an authoritative reference or standards implementation. 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 2026-09-29T14:52:32.152775+00:00.

Case digest / 80a132abc3b48905ac4db71ba54bb6cd02e9334e20956bdc3f3170fdf35a2e3b