FA-3791 / Parsing / Open access

A physical continuation inserts a semantic space · case 01

A physical continuation inserts a semantic space.

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: Remove every literal backslash-LF pair before interpreting any other text.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Remove every literal backslash-LF pair before interpreting any other text.

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

Case contract

Remove every literal backslash-LF pair before interpreting any other text.

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.replace(chr(92)+chr(10),' ')
    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('ab\\\ncd'), 'abcd')
check('boundary 2', solve('a\nb'), 'a\nb')
check('boundary 3', solve('a\\b'), 'a\\b')
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	`ab cd`	`abcd`	Failed
boundary 2	`a b`	`a b`	Passed
boundary 3	`a\b`	`a\b`	Passed
boundary 4			Passed

SHA-256 / d90897d3cf9bc410b4d034c77e26b91de5b8a3682fb53c835a2fd04f5458ee95

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 x.replace(chr(92),'').replace(chr(10),'')
    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('ab\\\ncd'), 'abcd')
check('boundary 2', solve('a\nb'), 'a\nb')
check('boundary 3', solve('a\\b'), 'a\\b')
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	`abcd`	`abcd`	Passed
boundary 2	`ab`	`a b`	Failed
boundary 3	`ab`	`a\b`	Failed
boundary 4			Passed

SHA-256 / 3bf50a1296add91e51422dc07c6edf29070961da39b4d542faa15a6c2d3825e8

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 x.replace(chr(92)+chr(10),'')
    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('ab\\\ncd'), 'abcd')
check('boundary 2', solve('a\nb'), 'a\nb')
check('boundary 3', solve('a\\b'), 'a\\b')
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	`abcd`	`abcd`	Passed
boundary 2	`a b`	`a b`	Passed
boundary 3	`a\b`	`a\b`	Passed
boundary 4			Passed

SHA-256 / 643c00cca4acf8d6a3ec606fc3c291e48cdfb6da6c83b6baaa6f42659ffbf420

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 2026-09-29T14:37:31.155759+00:00.

Case digest / ae36877d65090f1471a8bfba94f9db5778f82202782afc3cbb9917f6692d3ef9