FA-3821 / Serialization / Open access

Escaped template braces are treated as placeholders · case 01

Escaped template braces are treated as placeholders.

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: Apply Python string formatting with a=one, including doubled literal braces.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Apply Python string formatting with a=one, including doubled literal braces.

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

Case contract

Apply Python string formatting with a=one, including doubled literal braces.

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('{a}','one')
    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}}'), '{a}')
check('boundary 2', solve('{a}'), 'one')
check('boundary 3', solve('{{{a}}}'), '{one}')
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	`{one}`	`{a}`	Failed
boundary 2	`one`	`one`	Passed
boundary 3	`{{one}}`	`{one}`	Failed
boundary 4	`plain`	`plain`	Passed

SHA-256 / 35979a1b4a07f1b371da449046abb9540c1a41531415328389ea4839e9a1fcd1

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('{{','{').replace('}}','}').replace('{a}','one')
    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}}'), '{a}')
check('boundary 2', solve('{a}'), 'one')
check('boundary 3', solve('{{{a}}}'), '{one}')
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	`one`	`{a}`	Failed
boundary 2	`one`	`one`	Passed
boundary 3	`{one}`	`{one}`	Passed
boundary 4	`plain`	`plain`	Passed

SHA-256 / e095023a1a5b9ebfd56d461da0390324fe1d60e0d8523e2e5bbadac7c3aa2c05

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.format(a='one')
    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}}'), '{a}')
check('boundary 2', solve('{a}'), 'one')
check('boundary 3', solve('{{{a}}}'), '{one}')
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	`{a}`	`{a}`	Passed
boundary 2	`one`	`one`	Passed
boundary 3	`{one}`	`{one}`	Passed
boundary 4	`plain`	`plain`	Passed

SHA-256 / 29790188fd21aae6138efddddcf185cf72bb0012e785bcebb6c44e3ccc27ab8b

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 2026-09-29T14:37:31.380563+00:00.

Case digest / b12f915ccc93450b5de843fd30ed52fc6d77057d2c6374cabec498f529a2b07a