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A compatibility fraction remains opaque · case 01

A compatibility fraction remains opaque.

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: Produce NFKD, including compatibility fractions and decomposed accents.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Produce NFKD, including compatibility fractions and decomposed accents.

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

Case contract

Produce NFKD, including compatibility fractions and decomposed accents.

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 unicodedata.normalize('NFD', 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('½'), '1⁄2')
check('boundary 2', solve('é'), 'é')
check('boundary 3', solve('ﬀ'), 'ff')
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	`½`	`1⁄2`	Failed
boundary 2	`é`	`é`	Passed
boundary 3	`ﬀ`	`ff`	Failed
boundary 4			Passed

SHA-256 / fc90146425601140c1132e2c2abc37a6c0f02dc49b291034472b453b1f22d955

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 unicodedata.normalize('NFKC', 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('½'), '1⁄2')
check('boundary 2', solve('é'), 'é')
check('boundary 3', solve('ﬀ'), 'ff')
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	`1⁄2`	`1⁄2`	Passed
boundary 2	`é`	`é`	Failed
boundary 3	`ff`	`ff`	Passed
boundary 4			Passed

SHA-256 / dc05457d32dc37226b0528a6fed7a01f58c4689af3caf2cdaebaf27556c9fdbf

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 unicodedata.normalize('NFKD', 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('½'), '1⁄2')
check('boundary 2', solve('é'), 'é')
check('boundary 3', solve('ﬀ'), 'ff')
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	`1⁄2`	`1⁄2`	Passed
boundary 2	`é`	`é`	Passed
boundary 3	`ff`	`ff`	Passed
boundary 4			Passed

SHA-256 / 19328462164596249105952a97bfd82a9550377ea2e71cb3c6b6fef7bd08ba14

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 2026-09-29T14:37:18.020685+00:00.

Case digest / 8f454bbb34079c33aa67e9e9e1aaa593a8b61d5b59685619638e12d39501ec1e