FA-3786 / Text processing / Open access

CRLF normalization creates duplicate newlines · case 01

CRLF normalization creates duplicate newlines.

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: Normalize CRLF and lone CR to LF, preserving all other code points.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Normalize CRLF and lone CR to LF, preserving all other code points.

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

Case contract

Normalize CRLF and lone CR to LF, preserving all other code points.

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('\r','\n')
    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\r\nb'), 'a\nb')
check('boundary 2', solve('a\rb'), 'a\nb')
check('boundary 3', solve('a\n'), 'a\n')
check('boundary 4', solve('\u2028'), '\u2028')
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	`a b`	`a b`	Passed
boundary 3	`a`	`a`	Passed
boundary 4			Passed

SHA-256 / 9d5560f352375ad3f2755884c46e883df4ca26e49b1bfba58eb5e66722ad5bb8

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('\r\n','\n')
    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\r\nb'), 'a\nb')
check('boundary 2', solve('a\rb'), 'a\nb')
check('boundary 3', solve('a\n'), 'a\n')
check('boundary 4', solve('\u2028'), '\u2028')
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	`a b`	`a b`	Failed
boundary 3	`a`	`a`	Passed
boundary 4			Passed

SHA-256 / 4cb45e915c1832ffd41a88ad43e445b4de3da17f093fe907a56b934846c60f39

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('\r\n','\n').replace('\r','\n')
    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\r\nb'), 'a\nb')
check('boundary 2', solve('a\rb'), 'a\nb')
check('boundary 3', solve('a\n'), 'a\n')
check('boundary 4', solve('\u2028'), '\u2028')
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	`a b`	`a b`	Passed
boundary 3	`a`	`a`	Passed
boundary 4			Passed

SHA-256 / 844bee6ae2648498c32d73acf2c3951d01608db20152d774417a8263fa63f7e3

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 2026-09-29T14:37:30.968113+00:00.

Case digest / 0ab119d4e1c56e9c7e384813578a4e53187b81337ea19a1f23c553afb77a071f