FA-47546 / Delimited text / Open access

Each section body row overwrites its header · case 01

A structured table violates the declared record or column contract.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The header transition never moves the section into body mode.

THE FAILURE

The header transition never moves the section into body mode.

Unsuccessful approach: Using column width as the transition condition breaks single-column sections.

Case contract

Read a bounded sectioned TSV stream: @name starts a new table, the next record is its header, subsequent records its data. Names are unique and nonempty. A blank line closes a section; body records outside sections and sections without headers reject. Return ordered [name, header, rows] sections.

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):
    sections, current, needs_header = [], None, False
    for line in data:
        if line.startswith('%'):
            if current is not None and needs_header: return None
            name = line[1:]
            if not name or any(s[0] == name for s in sections): return None
            current = [name, [], []]
            sections.append(current)
            needs_header = True
        elif line == '':
            if needs_header: return None
            current = None
        elif current is None: return None
        elif needs_header:
            current[1] = line.split('\t')
            needs_header = True
        else: current[2].append(line.split('\t'))
    if needs_header: return None
    return sections
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('two sections', solve(_vary(['%one', 'a\tb', '@\tz', '%two', 'x', 'q'])), _vary([['one', ['a', 'b'], [['@', 'z']]], ['two', ['x'], [['q']]]]))
check('section close', solve(_vary(['%one', 'a', 'x', '', 'orphan'])), _vary(None))
check('empty section', solve(_vary(['%one', '%two', 'a'])), _vary(None))
check('missing eof header', solve(_vary(['%one'])), _vary(None))
check('duplicate', solve(_vary(['%one', 'a', '%one', 'b'])), _vary(None))
check('empty name', solve(_vary(['%', 'a'])), _vary(None))
check('normal', solve(_vary(['%one', 'a', '%'])), _vary(None))
check('zero', solve(_vary([])), _vary([]))
check('body control', solve(_vary(['%one', 'a', 'cell', 'two'])), _vary([['one', ['a'], [['cell'], ['two']]]]))
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
two sections	`None`	`[['one', ['a', 'b'], [['cell', 'z']]], ['two', ['x'], [['q']]]]`	Failed
section close	`None`	`None`	Passed
empty section	`None`	`None`	Passed
missing eof header	`None`	`None`	Passed
duplicate	`None`	`None`	Passed
empty name	`None`	`None`	Passed
normal	`None`	`None`	Passed
zero	`[]`	`[]`	Passed
body control	`None`	`[['one', ['a'], [['cell'], ['two']]]]`	Failed

SHA-256 / 299ffb3195be3f6c7d5c546273c8fc99f71a8eecf9789227b352de743ca1c6d7

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):
    sections, current, needs_header = [], None, False
    for line in data:
        if line.startswith('%'):
            if current is not None and needs_header: return None
            name = line[1:]
            if not name or any(s[0] == name for s in sections): return None
            current = [name, [], []]
            sections.append(current)
            needs_header = True
        elif line == '':
            if needs_header: return None
            current = None
        elif current is None: return None
        elif needs_header:
            current[1] = line.split('\t')
            needs_header = len(current[1]) == 1
        else: current[2].append(line.split('\t'))
    if needs_header: return None
    return sections
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('two sections', solve(_vary(['%one', 'a\tb', '@\tz', '%two', 'x', 'q'])), _vary([['one', ['a', 'b'], [['@', 'z']]], ['two', ['x'], [['q']]]]))
check('section close', solve(_vary(['%one', 'a', 'x', '', 'orphan'])), _vary(None))
check('empty section', solve(_vary(['%one', '%two', 'a'])), _vary(None))
check('missing eof header', solve(_vary(['%one'])), _vary(None))
check('duplicate', solve(_vary(['%one', 'a', '%one', 'b'])), _vary(None))
check('empty name', solve(_vary(['%', 'a'])), _vary(None))
check('normal', solve(_vary(['%one', 'a', '%'])), _vary(None))
check('zero', solve(_vary([])), _vary([]))
check('body control', solve(_vary(['%one', 'a', 'cell', 'two'])), _vary([['one', ['a'], [['cell'], ['two']]]]))
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
two sections	`None`	`[['one', ['a', 'b'], [['cell', 'z']]], ['two', ['x'], [['q']]]]`	Failed
section close	`None`	`None`	Passed
empty section	`None`	`None`	Passed
missing eof header	`None`	`None`	Passed
duplicate	`None`	`None`	Passed
empty name	`None`	`None`	Passed
normal	`None`	`None`	Passed
zero	`[]`	`[]`	Passed
body control	`None`	`[['one', ['a'], [['cell'], ['two']]]]`	Failed

SHA-256 / 439537689e9597a16f22a7c9d5c3b4e407aec49c3d4a5406396cf901879deab7

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 9 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.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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 2026-09-29T14:44:42.629573+00:00.

Case digest / b4b0f519cbf460639a730a575c78c85e74a978a34ec7bb01145d8feea5fac04a