FA-3191 / Delimited text / Open access

CSV trimming changes a quoted cell value · case 01

CSV trimming changes a quoted cell value.

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: Read a CSV row retaining leading spaces in unquoted fields and spaces inside quoted fields.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Read a CSV row retaining leading spaces in unquoted fields and spaces inside quoted fields.

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

Case contract

Read a CSV row retaining leading spaces in unquoted fields and spaces inside quoted fields.

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 [v.strip() for v in next(csv.reader([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('a, b'), ['a', ' b'])
check('boundary 4', solve('a,b'), ['a', 'b'])
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	`['a', 'b']`	`['a', ' b']`	Failed
boundary 4	`['a', 'b']`	`['a', 'b']`	Passed

SHA-256 / e47dc600c24cbea15e1a21c58e8c85154ba2932661142e7702134eccfca82a49

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 next(csv.reader([x],skipinitialspace=True))
    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('a, b'), ['a', ' b'])
check('boundary 4', solve('a,b'), ['a', 'b'])
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']`	Passed
boundary 3	`['a', 'b']`	`['a', ' b']`	Failed
boundary 4	`['a', 'b']`	`['a', 'b']`	Passed

SHA-256 / 1a681940bb85650fd589fcc5730c42cf12eeefd54dc256e034a4d28b0b6c6a9b

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 next(csv.reader([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('a, b'), ['a', ' b'])
check('boundary 4', solve('a,b'), ['a', 'b'])
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	`['a', ' b']`	`['a', ' b']`	Passed
boundary 4	`['a', 'b']`	`['a', 'b']`	Passed

SHA-256 / 06c2b16a92856d9f166fd9baa877fc02e3f1da3bc450c8f7dd03d6b9337978d0

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 2026-09-29T14:37:22.554845+00:00.

Case digest / b969c150d6e60499ed1cd91f3cab8c434a07c6629bc485ba7a285c8604e67964