FA-3936 / Encodings / Open access

A literal plus is not escaped in UTF-7 · case 01

A literal plus is not escaped in UTF-7.

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: Encode Unicode text as standard UTF-7 ASCII.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Encode Unicode text as standard UTF-7 ASCII.

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

Case contract

Encode Unicode text as standard UTF-7 ASCII.

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
    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('+'), '+-')
check('boundary 2', solve('é'), '+AOk-')
check('boundary 3', solve('a+b'), 'a+-b')
check('boundary 4', solve('plain'), 'plain')
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	`+`	`+-`	Failed
boundary 2	`é`	`+AOk-`	Failed
boundary 3	`a+b`	`a+-b`	Failed
boundary 4	`plain`	`plain`	Passed

SHA-256 / 1f887476598c2cf8eb575d381ee8d17d7442923da0f420da0022f899dca48a7c

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('+','+-')
    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('+'), '+-')
check('boundary 2', solve('é'), '+AOk-')
check('boundary 3', solve('a+b'), 'a+-b')
check('boundary 4', solve('plain'), 'plain')
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	`+-`	`+-`	Passed
boundary 2	`é`	`+AOk-`	Failed
boundary 3	`a+-b`	`a+-b`	Passed
boundary 4	`plain`	`plain`	Passed

SHA-256 / a8d7d1f426d556f2c730da2f0f308ff23c2752076e2fe8fc3f02f3778ddc2f35

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.encode('utf-7').decode('ascii')
    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('+'), '+-')
check('boundary 2', solve('é'), '+AOk-')
check('boundary 3', solve('a+b'), 'a+-b')
check('boundary 4', solve('plain'), 'plain')
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	`+-`	`+-`	Passed
boundary 2	`+AOk-`	`+AOk-`	Passed
boundary 3	`a+-b`	`a+-b`	Passed
boundary 4	`plain`	`plain`	Passed

SHA-256 / 8d64b7074d662bb78c538bf058f3d0ee6449ed0e3836d8789d65d34982e54616

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 2026-09-29T14:37:33.272297+00:00.

Case digest / 031c7810aac7c36b71d4191bd58aabc235144fece403dbfc3d07e32afc941a59