FA-48796 / Delimited text / Open access
The next CSV record starts on the prior ending physical line · case 01
A structured table violates the declared record or column contract.
ROOT CAUSE
The next CSV record starts on the prior ending physical line.
VERIFIED REPAIR
Preserve the named invariant at the faulty decision: start=end+1
Unsuccessful approach: The alternate implementation still violates the same declared invariant: the next csv record starts on the prior ending physical line.
Case contract
Parse bounded valid CSV text using Python csv.reader and report each logical row with inclusive one-based physical start/end line numbers. Quoted embedded newlines count as physical lines. Empty input gives no rows; blank physical lines are zero-cell rows. Return [start,end,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):
import csv,io
reader=csv.reader(io.StringIO(data,newline=''))
out=[]; start=1
for cells in reader:
end=reader.line_num
out.append([start,end,cells])
start=end
return out
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multiline', solve(_vary('a,"x\ny"\nz,@\n')), _vary([[1, 2, ['a', 'x\ny']], [3, 3, ['z', '@']]]))
check('blank middle', solve(_vary('a\n\nz\n')), _vary([[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]]))
check('plain', solve(_vary('@,x\n')), _vary([[1, 1, ['@', 'x']]]))
check('CRLF', solve(_vary('"a\r\nb",z\r\n')), _vary([[1, 2, ['a\r\nb', 'z']]]))
check('empty', solve(_vary('')), _vary([]))
check('unterminated final', solve(_vary('@')), _vary([[1, 1, ['@']]]))
check('two multiline', solve(_vary('"a\nb"\n"c\nd"')), _vary([[1, 2, ['a\nb']], [3, 4, ['c\nd']]]))
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 |
|---|---|---|---|
| multiline | [[1, 2, ['a', 'x\ny']], [2, 3, ['z', 'cell']]] | [[1, 2, ['a', 'x\ny']], [3, 3, ['z', 'cell']]] | Failed |
| blank middle | [[1, 1, ['a']], [1, 2, []], [2, 3, ['z']]] | [[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]] | Failed |
| plain | [[1, 1, ['cell', 'x']]] | [[1, 1, ['cell', 'x']]] | Passed |
| CRLF | [[1, 2, ['a\r\nb', 'z']]] | [[1, 2, ['a\r\nb', 'z']]] | Passed |
| empty | [] | [] | Passed |
| unterminated final | [[1, 1, ['cell']]] | [[1, 1, ['cell']]] | Passed |
| two multiline | [[1, 2, ['a\nb']], [2, 4, ['c\nd']]] | [[1, 2, ['a\nb']], [3, 4, ['c\nd']]] | Failed |
SHA-256 / d09800a28d30581ebef1b4d19df3272e3e81756773def4820fe8820787b2282e
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):
import csv,io
reader=csv.reader(io.StringIO(data,newline=''))
out=[]; start=1
for cells in reader:
end=reader.line_num
out.append([start,end,cells])
start+=1
return out
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multiline', solve(_vary('a,"x\ny"\nz,@\n')), _vary([[1, 2, ['a', 'x\ny']], [3, 3, ['z', '@']]]))
check('blank middle', solve(_vary('a\n\nz\n')), _vary([[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]]))
check('plain', solve(_vary('@,x\n')), _vary([[1, 1, ['@', 'x']]]))
check('CRLF', solve(_vary('"a\r\nb",z\r\n')), _vary([[1, 2, ['a\r\nb', 'z']]]))
check('empty', solve(_vary('')), _vary([]))
check('unterminated final', solve(_vary('@')), _vary([[1, 1, ['@']]]))
check('two multiline', solve(_vary('"a\nb"\n"c\nd"')), _vary([[1, 2, ['a\nb']], [3, 4, ['c\nd']]]))
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 |
|---|---|---|---|
| multiline | [[1, 2, ['a', 'x\ny']], [2, 3, ['z', 'cell']]] | [[1, 2, ['a', 'x\ny']], [3, 3, ['z', 'cell']]] | Failed |
| blank middle | [[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]] | [[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]] | Passed |
| plain | [[1, 1, ['cell', 'x']]] | [[1, 1, ['cell', 'x']]] | Passed |
| CRLF | [[1, 2, ['a\r\nb', 'z']]] | [[1, 2, ['a\r\nb', 'z']]] | Passed |
| empty | [] | [] | Passed |
| unterminated final | [[1, 1, ['cell']]] | [[1, 1, ['cell']]] | Passed |
| two multiline | [[1, 2, ['a\nb']], [2, 4, ['c\nd']]] | [[1, 2, ['a\nb']], [3, 4, ['c\nd']]] | Failed |
SHA-256 / 0c6ec6f6113ddb242e35e60bf6e44e1b96586d961aaad3c9f066d9176ec63ad5
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):
import csv,io
reader=csv.reader(io.StringIO(data,newline=''))
out=[]; start=1
for cells in reader:
end=reader.line_num
out.append([start,end,cells])
start=end+1
return out
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('multiline', solve(_vary('a,"x\ny"\nz,@\n')), _vary([[1, 2, ['a', 'x\ny']], [3, 3, ['z', '@']]]))
check('blank middle', solve(_vary('a\n\nz\n')), _vary([[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]]))
check('plain', solve(_vary('@,x\n')), _vary([[1, 1, ['@', 'x']]]))
check('CRLF', solve(_vary('"a\r\nb",z\r\n')), _vary([[1, 2, ['a\r\nb', 'z']]]))
check('empty', solve(_vary('')), _vary([]))
check('unterminated final', solve(_vary('@')), _vary([[1, 1, ['@']]]))
check('two multiline', solve(_vary('"a\nb"\n"c\nd"')), _vary([[1, 2, ['a\nb']], [3, 4, ['c\nd']]]))
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 |
|---|---|---|---|
| multiline | [[1, 2, ['a', 'x\ny']], [3, 3, ['z', 'cell']]] | [[1, 2, ['a', 'x\ny']], [3, 3, ['z', 'cell']]] | Passed |
| blank middle | [[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]] | [[1, 1, ['a']], [2, 2, []], [3, 3, ['z']]] | Passed |
| plain | [[1, 1, ['cell', 'x']]] | [[1, 1, ['cell', 'x']]] | Passed |
| CRLF | [[1, 2, ['a\r\nb', 'z']]] | [[1, 2, ['a\r\nb', 'z']]] | Passed |
| empty | [] | [] | Passed |
| unterminated final | [[1, 1, ['cell']]] | [[1, 1, ['cell']]] | Passed |
| two multiline | [[1, 2, ['a\nb']], [3, 4, ['c\nd']]] | [[1, 2, ['a\nb']], [3, 4, ['c\nd']]] | Passed |
SHA-256 / c0dcd833e59189ee8c02f058ae4196f72cb98eb308059eff0a5c0abb27b2d4b0
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 2026-09-29T14:44:54.029136+00:00.
Case digest / 788b8906ea35994c0bb4c359f9eb75fcd55be2b7d8d786efb9d0159ade04ffd3