FA-47926 / Delimited text / Open access

Column-selector ranges retain one-based array offsets · case 01

A structured table violates the declared record or column contract.

Verified by executionVariant 1 · 11 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The selector parser fails to convert the lower endpoint origin.

VERIFIED REPAIR

Preserve the named invariant at the faulty decision: out.extend(range(start-1, end))

Unsuccessful approach: An extra subtraction includes the preceding physical column.

Case contract

Resolve an ordered comma column selector against width. Decimal selectors are one based, ranges a-b include both endpoints, and * adds every column not selected earlier. Explicit duplicate selections are retained. Reject malformed, reversed or out-of-bound numeric ranges. Return zero-based physical indexes.

Why this case matters

Delimited interchange needs explicit framing, schema and field semantics at ingestion and emission boundaries.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
def _vary(value):
    if value == '@END': return 3 + 4*N
    if isinstance(value, str): return value.replace('@', 'cell' * N)
    if isinstance(value, list): return [_vary(x) for x in value]
    if isinstance(value, dict): return {_vary(k): _vary(v) for k,v in value.items()}
    return value
N = 1
observations = []
def solve(data):
    out = []
    for token in data['selector'].split(','):
        if token == '*':
            out.extend(i for i in range(data['width']) if i not in out)
            continue
        parts = token.split('-')
        if len(parts) not in (1,2) or any(not p.isascii() or not p.isdecimal() for p in parts): return None
        start, end = int(parts[0]), int(parts[-1])
        if not 1 <= start <= end <= data['width']: return None
        out.extend(range(start, end))
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('ordered', solve(_vary({'selector': '3,1', 'width': 3})), _vary([2, 0]))
check('range', solve(_vary({'selector': '2-4', 'width': 4})), _vary([1, 2, 3]))
check('wildcard', solve(_vary({'selector': '2,*', 'width': 3})), _vary([1, 0, 2]))
check('duplicate', solve(_vary({'selector': '2,2', 'width': 3})), _vary([1, 1]))
check('reversed', solve(_vary({'selector': '3-1', 'width': 3})), _vary(None))
check('zero', solve(_vary({'selector': '0', 'width': 3})), _vary(None))
check('outside', solve(_vary({'selector': '4', 'width': 3})), _vary(None))
check('bad range', solve(_vary({'selector': '1-2-3', 'width': 3})), _vary(None))
check('empty', solve(_vary({'selector': '', 'width': 3})), _vary(None))
check('variable width', solve(_vary({'selector': '1,*', 'width': 4})), _vary([0, 1, 2, 3]))
check('variant selector width', solve({'selector':'1,*','width':N+2}), list(range(N+2)))
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
ordered	`[]`	`[2, 0]`	Failed
range	`[2, 3]`	`[1, 2, 3]`	Failed
wildcard	`[0, 1, 2]`	`[1, 0, 2]`	Failed
duplicate	`[]`	`[1, 1]`	Failed
reversed	`None`	`None`	Passed
zero	`None`	`None`	Passed
outside	`None`	`None`	Passed
bad range	`None`	`None`	Passed
empty	`None`	`None`	Passed
variable width	`[0, 1, 2, 3]`	`[0, 1, 2, 3]`	Passed
variant selector width	`[0, 1, 2]`	`[0, 1, 2]`	Passed

SHA-256 / e2ef4c63a039b8ad0cdabe5d7bc8006748640faf3c1daf8beb9f47749226dbe4

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
def _vary(value):
    if value == '@END': return 3 + 4*N
    if isinstance(value, str): return value.replace('@', 'cell' * N)
    if isinstance(value, list): return [_vary(x) for x in value]
    if isinstance(value, dict): return {_vary(k): _vary(v) for k,v in value.items()}
    return value
N = 1
observations = []
def solve(data):
    out = []
    for token in data['selector'].split(','):
        if token == '*':
            out.extend(i for i in range(data['width']) if i not in out)
            continue
        parts = token.split('-')
        if len(parts) not in (1,2) or any(not p.isascii() or not p.isdecimal() for p in parts): return None
        start, end = int(parts[0]), int(parts[-1])
        if not 1 <= start <= end <= data['width']: return None
        out.extend(range(max(start-2,0), end))
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('ordered', solve(_vary({'selector': '3,1', 'width': 3})), _vary([2, 0]))
check('range', solve(_vary({'selector': '2-4', 'width': 4})), _vary([1, 2, 3]))
check('wildcard', solve(_vary({'selector': '2,*', 'width': 3})), _vary([1, 0, 2]))
check('duplicate', solve(_vary({'selector': '2,2', 'width': 3})), _vary([1, 1]))
check('reversed', solve(_vary({'selector': '3-1', 'width': 3})), _vary(None))
check('zero', solve(_vary({'selector': '0', 'width': 3})), _vary(None))
check('outside', solve(_vary({'selector': '4', 'width': 3})), _vary(None))
check('bad range', solve(_vary({'selector': '1-2-3', 'width': 3})), _vary(None))
check('empty', solve(_vary({'selector': '', 'width': 3})), _vary(None))
check('variable width', solve(_vary({'selector': '1,*', 'width': 4})), _vary([0, 1, 2, 3]))
check('variant selector width', solve({'selector':'1,*','width':N+2}), list(range(N+2)))
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
ordered	`[1, 2, 0]`	`[2, 0]`	Failed
range	`[0, 1, 2, 3]`	`[1, 2, 3]`	Failed
wildcard	`[0, 1, 2]`	`[1, 0, 2]`	Failed
duplicate	`[0, 1, 0, 1]`	`[1, 1]`	Failed
reversed	`None`	`None`	Passed
zero	`None`	`None`	Passed
outside	`None`	`None`	Passed
bad range	`None`	`None`	Passed
empty	`None`	`None`	Passed
variable width	`[0, 1, 2, 3]`	`[0, 1, 2, 3]`	Passed
variant selector width	`[0, 1, 2]`	`[0, 1, 2]`	Passed

SHA-256 / e9ed5abf3a8a3c01b3093096b0cb7db972daed21479cccbae4c95c5c1cf201da

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
def _vary(value):
    if value == '@END': return 3 + 4*N
    if isinstance(value, str): return value.replace('@', 'cell' * N)
    if isinstance(value, list): return [_vary(x) for x in value]
    if isinstance(value, dict): return {_vary(k): _vary(v) for k,v in value.items()}
    return value
N = 1
observations = []
def solve(data):
    out = []
    for token in data['selector'].split(','):
        if token == '*':
            out.extend(i for i in range(data['width']) if i not in out)
            continue
        parts = token.split('-')
        if len(parts) not in (1,2) or any(not p.isascii() or not p.isdecimal() for p in parts): return None
        start, end = int(parts[0]), int(parts[-1])
        if not 1 <= start <= end <= data['width']: return None
        out.extend(range(start-1, end))
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('ordered', solve(_vary({'selector': '3,1', 'width': 3})), _vary([2, 0]))
check('range', solve(_vary({'selector': '2-4', 'width': 4})), _vary([1, 2, 3]))
check('wildcard', solve(_vary({'selector': '2,*', 'width': 3})), _vary([1, 0, 2]))
check('duplicate', solve(_vary({'selector': '2,2', 'width': 3})), _vary([1, 1]))
check('reversed', solve(_vary({'selector': '3-1', 'width': 3})), _vary(None))
check('zero', solve(_vary({'selector': '0', 'width': 3})), _vary(None))
check('outside', solve(_vary({'selector': '4', 'width': 3})), _vary(None))
check('bad range', solve(_vary({'selector': '1-2-3', 'width': 3})), _vary(None))
check('empty', solve(_vary({'selector': '', 'width': 3})), _vary(None))
check('variable width', solve(_vary({'selector': '1,*', 'width': 4})), _vary([0, 1, 2, 3]))
check('variant selector width', solve({'selector':'1,*','width':N+2}), list(range(N+2)))
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
ordered	`[2, 0]`	`[2, 0]`	Passed
range	`[1, 2, 3]`	`[1, 2, 3]`	Passed
wildcard	`[1, 0, 2]`	`[1, 0, 2]`	Passed
duplicate	`[1, 1]`	`[1, 1]`	Passed
reversed	`None`	`None`	Passed
zero	`None`	`None`	Passed
outside	`None`	`None`	Passed
bad range	`None`	`None`	Passed
empty	`None`	`None`	Passed
variable width	`[0, 1, 2, 3]`	`[0, 1, 2, 3]`	Passed
variant selector width	`[0, 1, 2]`	`[0, 1, 2]`	Passed

SHA-256 / 74afbb7e06e63c43d3bbd867097175cfafa89b4a57bf8a1323f72da59acdf1c5

Verification & scope

Deterministic bounded in-memory model. No claim of complete CSV or external format conformance. 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 2026-09-29T14:44:46.147261+00:00.

Case digest / 9e22aca4f6bb2e361804d8627ea851feee7f0d2fee63a29db3299b6ee15efbd4