FA-3241 / Markup / Open access

An empty XML element is treated as absent · case 01

An empty XML element is treated as absent.

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: Return whether root has a direct child named item, even when it has no children.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Return whether root has a direct child named item, even when it has no children.

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

Case contract

Return whether root has a direct child named item, even when it has no children.

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:
        node = ET.fromstring(x).find('item')
        return node is not None and len(node) > 0
    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('<r><item/></r>'), True)
check('boundary 2', solve('<r><item>x</item></r>'), True)
check('boundary 3', solve('<r/>'), False)
check('boundary 4', solve('<r><other/></r>'), False)
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	`False`	`True`	Failed
boundary 2	`False`	`True`	Failed
boundary 3	`False`	`False`	Passed
boundary 4	`False`	`False`	Passed

SHA-256 / 9ea848e7974e5ef18817677fd95cb43c7442f057ede7d4f449eb195d01c96eff

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 ET.fromstring(x).findtext('item') not in (None,'')
    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('<r><item/></r>'), True)
check('boundary 2', solve('<r><item>x</item></r>'), True)
check('boundary 3', solve('<r/>'), False)
check('boundary 4', solve('<r><other/></r>'), False)
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	`False`	`True`	Failed
boundary 2	`True`	`True`	Passed
boundary 3	`False`	`False`	Passed
boundary 4	`False`	`False`	Passed

SHA-256 / 7b9d7c9f27fa5ffb1420b3aa368ab39f5e6cd353b9bd7eb34951dc69ff3b96c9

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 ET.fromstring(x).find('item') is not None
    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('<r><item/></r>'), True)
check('boundary 2', solve('<r><item>x</item></r>'), True)
check('boundary 3', solve('<r/>'), False)
check('boundary 4', solve('<r><other/></r>'), False)
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	`True`	`True`	Passed
boundary 2	`True`	`True`	Passed
boundary 3	`False`	`False`	Passed
boundary 4	`False`	`False`	Passed

SHA-256 / efac9e92dd1b5aae562ba93c6c64c31028add2ad03d161c4160c1df539e146b4

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 2026-09-29T14:37:23.226904+00:00.

Case digest / c523f2d02748ce578c61185bca54abc5364a206a8ea5bd2f8f0283df674ef944