FA-47871 / Delimited text / Open access

Footer verification counts the header as a body record · 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 declared count is compared with a header-inclusive tally.

THE FAILURE

The declared count is compared with a header-inclusive tally.

Unsuccessful approach: Checking only undercounts accepts a footer claiming absent rows.

Case contract

Read a comma table with header H,<column names>, body D,<values>, and final F,<body count>. Reject missing or misplaced footer, count mismatch, malformed tags, unequal body width, and missing header. Count only body records. Return body arrays.

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):
    if not data or not data[0].startswith('H,'): return None
    width = len(data[0].split(',')) - 1
    rows, closed = [], False
    for line in data[1:]:
        if closed: return None
        cells = line.split(',')
        if cells[0] == 'D':
            if len(cells) - 1 != width: return None
            rows.append(cells[1:])
        elif cells[0] == 'F':
            if len(cells) != 2 or not cells[1].isascii() or not cells[1].isdecimal(): return None
            if int(cells[1]) != len(rows) + 1: return None
            closed = True
        else: return None
    if not closed: return None
    return rows
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('table', solve(_vary(['H,a,b', 'D,@,x', 'D,y,z', 'F,2'])), _vary([['@', 'x'], ['y', 'z']]))
check('count mismatch', solve(_vary(['H,a', 'D,@', 'F,2'])), _vary(None))
check('after footer', solve(_vary(['H,a', 'F,0', 'D,@'])), _vary(None))
check('missing footer', solve(_vary(['H,a', 'D,@'])), _vary(None))
check('empty body', solve(_vary(['H,a', 'F,0'])), _vary([]))
check('bad tag', solve(_vary(['H,a', 'X,@', 'F,1'])), _vary(None))
check('bad width', solve(_vary(['H,a,b', 'D,@', 'F,1'])), _vary(None))
check('missing header', solve(_vary(['D,@', 'F,1'])), _vary(None))
check('second footer', solve(_vary(['H,a', 'F,0', 'F,0'])), _vary(None))
check('bad count', solve(_vary(['H,a', 'F,-1'])), _vary(None))
check('unknown not counted', solve(_vary(['H,a', 'X,@', 'F,0'])), _vary(None))
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
table	`None`	`[['cell', 'x'], ['y', 'z']]`	Failed
count mismatch	`[['cell']]`	`None`	Failed
after footer	`None`	`None`	Passed
missing footer	`None`	`None`	Passed
empty body	`None`	`[]`	Failed
bad tag	`None`	`None`	Passed
bad width	`None`	`None`	Passed
missing header	`None`	`None`	Passed
second footer	`None`	`None`	Passed
bad count	`None`	`None`	Passed
unknown not counted	`None`	`None`	Passed

SHA-256 / dcce55ff67e4a66e4aea91e523a3bb6dff412dd42f258764f06b1a7962d90498

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):
    if not data or not data[0].startswith('H,'): return None
    width = len(data[0].split(',')) - 1
    rows, closed = [], False
    for line in data[1:]:
        if closed: return None
        cells = line.split(',')
        if cells[0] == 'D':
            if len(cells) - 1 != width: return None
            rows.append(cells[1:])
        elif cells[0] == 'F':
            if len(cells) != 2 or not cells[1].isascii() or not cells[1].isdecimal(): return None
            if int(cells[1]) < len(rows): return None
            closed = True
        else: return None
    if not closed: return None
    return rows
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('table', solve(_vary(['H,a,b', 'D,@,x', 'D,y,z', 'F,2'])), _vary([['@', 'x'], ['y', 'z']]))
check('count mismatch', solve(_vary(['H,a', 'D,@', 'F,2'])), _vary(None))
check('after footer', solve(_vary(['H,a', 'F,0', 'D,@'])), _vary(None))
check('missing footer', solve(_vary(['H,a', 'D,@'])), _vary(None))
check('empty body', solve(_vary(['H,a', 'F,0'])), _vary([]))
check('bad tag', solve(_vary(['H,a', 'X,@', 'F,1'])), _vary(None))
check('bad width', solve(_vary(['H,a,b', 'D,@', 'F,1'])), _vary(None))
check('missing header', solve(_vary(['D,@', 'F,1'])), _vary(None))
check('second footer', solve(_vary(['H,a', 'F,0', 'F,0'])), _vary(None))
check('bad count', solve(_vary(['H,a', 'F,-1'])), _vary(None))
check('unknown not counted', solve(_vary(['H,a', 'X,@', 'F,0'])), _vary(None))
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
table	`[['cell', 'x'], ['y', 'z']]`	`[['cell', 'x'], ['y', 'z']]`	Passed
count mismatch	`[['cell']]`	`None`	Failed
after footer	`None`	`None`	Passed
missing footer	`None`	`None`	Passed
empty body	`[]`	`[]`	Passed
bad tag	`None`	`None`	Passed
bad width	`None`	`None`	Passed
missing header	`None`	`None`	Passed
second footer	`None`	`None`	Passed
bad count	`None`	`None`	Passed
unknown not counted	`None`	`None`	Passed

SHA-256 / 1a6f2ab1d5b17047491b0dcc9be5fafc4b16eff886987325974b590696ab967d

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 11 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

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 2026-09-29T14:44:45.722580+00:00.

Case digest / cb87faee42abf6d557dc10102eead2c485d6b3b32872fc4a097f612cb2b19d06