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Markdown escaping modifies alphanumeric text · case 01

Markdown escaping modifies alphanumeric text.

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: Backslash-escape ASCII punctuation only; leave letters, whitespace and non-ASCII characters literal.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Backslash-escape ASCII punctuation only; leave letters, whitespace and non-ASCII characters literal.

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

Case contract

Backslash-escape ASCII punctuation only; leave letters, whitespace and non-ASCII characters literal.

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 ''.join('\\'+c for c in 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('a b'), 'a b')
check('boundary 3', solve('é'), 'é')
check('boundary 4', solve('[x]'), '\\[x\\]')
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`	Failed
boundary 3	`\é`	`é`	Failed
boundary 4	`\[\x\]`	`\[x\]`	Failed

SHA-256 / fdd88b33d922439ee00a1c2a6b2685a6a6a47782d19e4cdecf5bc39618898d9a

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 ''.join('\\'+c if not c.isalnum() else c for c in 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('a b'), 'a b')
check('boundary 3', solve('é'), 'é')
check('boundary 4', solve('[x]'), '\\[x\\]')
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	`é`	`é`	Passed
boundary 4	`\[x\]`	`\[x\]`	Passed

SHA-256 / 8affa09fbace4d2796c773ac704bbef1ee305bbe2eb48eb85bcd28b65e925069

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 ''.join('\\'+c if c in string.punctuation else c for c in 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('a b'), 'a b')
check('boundary 3', solve('é'), 'é')
check('boundary 4', solve('[x]'), '\\[x\\]')
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	`é`	`é`	Passed
boundary 4	`\[x\]`	`\[x\]`	Passed

SHA-256 / 0fc4851cde39e73d367344ac201e633b147440b9229d4b6e6f31030f26b7bca2

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 2026-09-29T14:37:34.436225+00:00.

Case digest / 815bb47f51546dce326211b1284963d39c1b822f8c585e1aea78d269b5dc2c42