FA-3896 / Parsing / Open access

Quoted empty list entries are discarded · case 01

Quoted empty list entries are discarded.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The implementation applies an operation whose text or grammar semantics violate this contract: Parse space-separated POSIX words and retain quoted empty values.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Parse space-separated POSIX words and retain quoted empty values.

Unsuccessful approach: The attempted repair handles the primary example but still violates a separate boundary of the same contract.

Case contract

Parse space-separated POSIX words and retain quoted empty values.

Why this case matters

A local executable model for consumers of structured text; oracle values are authored literals, not outputs copied from the repaired implementation.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return x.split()
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve("a '' b"), ['a', '', 'b'])
check('boundary 2', solve('""'), [''])
check('boundary 3', solve('a "b c"'), ['a', 'b c'])
check('boundary 4', solve(''), [])
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
boundary 1	`['a', "''", 'b']`	`['a', '', 'b']`	Failed
boundary 2	`['""']`	`['']`	Failed
boundary 3	`['a', '"b', 'c"']`	`['a', 'b c']`	Failed
boundary 4	`[]`	`[]`	Passed

SHA-256 / 0db1664b48747d9739cd0dc879121b98a0dc6d1653042320dc8c5705f70c77a7

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return [v for v in shlex.split(x) if v]
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve("a '' b"), ['a', '', 'b'])
check('boundary 2', solve('""'), [''])
check('boundary 3', solve('a "b c"'), ['a', 'b c'])
check('boundary 4', solve(''), [])
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
boundary 1	`['a', 'b']`	`['a', '', 'b']`	Failed
boundary 2	`[]`	`['']`	Failed
boundary 3	`['a', 'b c']`	`['a', 'b c']`	Passed
boundary 4	`[]`	`[]`	Passed

SHA-256 / e9404cfc5b3c250068f5a0449b6ae51b4aa3505ddac11b40687993f64c6ef04a

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return shlex.split(x)
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve("a '' b"), ['a', '', 'b'])
check('boundary 2', solve('""'), [''])
check('boundary 3', solve('a "b c"'), ['a', 'b c'])
check('boundary 4', solve(''), [])
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
boundary 1	`['a', '', 'b']`	`['a', '', 'b']`	Passed
boundary 2	`['']`	`['']`	Passed
boundary 3	`['a', 'b c']`	`['a', 'b c']`	Passed
boundary 4	`[]`	`[]`	Passed

SHA-256 / db5ae8a8e91bb412cdb711b82def1b6c66e84f0104203b487de6bf4c3268c42d

Verification & scope

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 2026-09-29T14:37:32.429606+00:00.

Case digest / ab4af177bdb76394ac18949f1ec7ca1f86387c893fa138e2d0279a1fc35889ea