FA-48376 / Delimited text / Open access

Every nonnull bitmap slot receives the first payload value · case 01

A structured table violates the declared record or column contract.

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

ROOT CAUSE

Every nonnull bitmap slot receives the first payload value.

THE FAILURE

Every nonnull bitmap slot receives the first payload value.

Unsuccessful approach: The alternate implementation still violates the same declared invariant: every nonnull bitmap slot receives the first payload value.

Case contract

Decode bitmap|comma-payload rows. Bitmap consists of 0 and 1; 1 denotes null and consumes no payload, 0 consumes one payload field. Empty payload encodes zero fields only when bitmap has no zero bits; otherwise it is one empty field. Reject leftover or insufficient values. Return logical cells.

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):
    parts=data.split('|',1)
    if len(parts)!=2: return None
    bits,payload=parts
    if any(bit not in '01' for bit in bits): return None
    values=payload.split(',') if payload or '0' in bits else []
    out=[]; cursor=0
    for bit in bits:
        if bit=='1': out.append(None)
        else:
            if cursor>=len(values): return None
            out.append(values[0]); cursor+=1
    if cursor!=len(values): return None
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('mixed', solve(_vary('010|@,z')), _vary(['@', None, 'z']))
check('all null', solve(_vary('111|')), _vary([None, None, None]))
check('empty text', solve(_vary('0|')), _vary(['']))
check('insufficient', solve(_vary('00|x')), _vary(None))
check('extra', solve(_vary('1|x')), _vary(None))
check('empty bitmap', solve(_vary('|')), _vary([]))
check('invalid bit', solve(_vary('02|x,y')), _vary(None))
check('several nulls', solve(_vary('1101|@')), _vary([None, None, '@', 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
mixed	`['cell', None, 'cell']`	`['cell', None, 'z']`	Failed
all null	`[None, None, None]`	`[None, None, None]`	Passed
empty text	`['']`	`['']`	Passed
insufficient	`None`	`None`	Passed
extra	`None`	`None`	Passed
empty bitmap	`[]`	`[]`	Passed
invalid bit	`None`	`None`	Passed
several nulls	`[None, None, 'cell', None]`	`[None, None, 'cell', None]`	Passed

SHA-256 / fbc19cf1b2a32a3a1ac14073a46e8d670f6d2e1fe4675cae8926037d77769e7d

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):
    parts=data.split('|',1)
    if len(parts)!=2: return None
    bits,payload=parts
    if any(bit not in '01' for bit in bits): return None
    values=payload.split(',') if payload or '0' in bits else []
    out=[]; cursor=0
    for bit in bits:
        if bit=='1': out.append(None)
        else:
            if cursor>=len(values): return None
            out.append(values[-1]); cursor+=1
    if cursor!=len(values): return None
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('mixed', solve(_vary('010|@,z')), _vary(['@', None, 'z']))
check('all null', solve(_vary('111|')), _vary([None, None, None]))
check('empty text', solve(_vary('0|')), _vary(['']))
check('insufficient', solve(_vary('00|x')), _vary(None))
check('extra', solve(_vary('1|x')), _vary(None))
check('empty bitmap', solve(_vary('|')), _vary([]))
check('invalid bit', solve(_vary('02|x,y')), _vary(None))
check('several nulls', solve(_vary('1101|@')), _vary([None, None, '@', 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
mixed	`['z', None, 'z']`	`['cell', None, 'z']`	Failed
all null	`[None, None, None]`	`[None, None, None]`	Passed
empty text	`['']`	`['']`	Passed
insufficient	`None`	`None`	Passed
extra	`None`	`None`	Passed
empty bitmap	`[]`	`[]`	Passed
invalid bit	`None`	`None`	Passed
several nulls	`[None, None, 'cell', None]`	`[None, None, 'cell', None]`	Passed

SHA-256 / 2752714ab5204a9dfa5e38c0f38466c2a2999c283f3d426df1361705ccb3af57

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.

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 2026-09-29T14:44:50.233271+00:00.

Case digest / 526666cb25bc7b82b7e58944ff58514b4bdf7edef4a7a1c43afa02e968e39fb3