FA-6601 / HTTP semantics / Open access

Retry classification includes replacement and deletion methods · case 01

Retry classification includes replacement and deletion methods.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The faulty implementation uses `method in ('GET', 'HEAD')` for the idempotent-methods decision.

VERIFIED REPAIR

Apply the explicit idempotent-methods contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `method != 'POST'` and still violates a separate fixture.

Case contract

Retry classification includes replacement and deletion methods: return the result specified by the explicit input/output boundary fixtures.

Why this case matters

This deterministic http semantics model isolates the idempotent-methods policy at a network component boundary.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(method):
    return method in ('GET', 'HEAD')
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('PUT'), True)", "check('fixture 2', solve('DELETE'), True)", "check('fixture 3', solve('PATCH'), False)", "check('fixture 4', solve('GET'), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
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
fixture 2	`False`	`True`	Failed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`True`	Failed

SHA-256 / 5b4af012095cc204bc452c4a14c9fed4e27d73b65866888c82f3a14f5bec4c7d

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(method):
    return method != 'POST'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('PUT'), True)", "check('fixture 2', solve('DELETE'), True)", "check('fixture 3', solve('PATCH'), False)", "check('fixture 4', solve('GET'), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
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
fixture 2	`True`	`True`	Passed
fixture 3	`True`	`False`	Failed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / 82647d2a99f6550639dad0f3450fd2eb01535875ea5bcf8fc94bacbea02da09f

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(method):
    return method in ('GET', 'HEAD', 'OPTIONS', 'TRACE', 'PUT', 'DELETE')
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('PUT'), True)", "check('fixture 2', solve('DELETE'), True)", "check('fixture 3', solve('PATCH'), False)", "check('fixture 4', solve('GET'), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
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
fixture 2	`True`	`True`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / da377781efe8be19b9a8f1e0528c26236726f51cd021d64826185a202f7c9ade

Verification & scope

Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. 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 2026-09-29T14:38:03.662273+00:00.

Case digest / d4e669ef573bb476213322e82d134883a905bf62f16d7a6b82568c6827641350