FA-6876 / Content negotiation / Open access
Compression benefit includes content coding overhead · case 01
Compression benefit includes content coding overhead.
ROOT CAUSE
The faulty implementation uses `min(candidates,key=lambda c:c[1],default=(None,))[0]` for the compression-benefit-includes-content-coding-overhead decision.
VERIFIED REPAIR
Apply the explicit compression-benefit-includes-content-coding-overhead contract, including the tested boundary and negative cases.
Unsuccessful approach: The attempted repair uses `min((c for c in candidates if c[1]+overhead <= raw),key=lambda c:c[1],default=(None,))[0]` and still violates a separate fixture.
Case contract
Given raw, candidates, overhead, compression benefit includes content coding overhead. Return the protocol decision or transformed value; fields are validated and fixtures state boundary outcomes.
Why this case matters
This deterministic content negotiation model isolates the compression-benefit-includes-content-coding-overhead 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(raw, candidates, overhead):
return min(candidates,key=lambda c:c[1],default=(None,))[0]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(100, [('gzip', 95)], 10), None)", "check('fixture 2', solve(100, [('gzip', 90)], 10), None)", "check('fixture 3', solve(100, [('gzip', 70), ('br', 60)], 10), 'br')", "check('fixture 4', solve(100, [], 10), None)"]
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 | gzip | None | Failed |
| fixture 3 | br | br | Passed |
| fixture 4 | None | None | Passed |
| fixture 1 | gzip | None | Failed |
SHA-256 / af054409cc5b6d662d9ee035e75dc8965b5cb9805590e2a26ce8d91572e40bd9
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(raw, candidates, overhead):
return min((c for c in candidates if c[1]+overhead <= raw),key=lambda c:c[1],default=(None,))[0]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(100, [('gzip', 95)], 10), None)", "check('fixture 2', solve(100, [('gzip', 90)], 10), None)", "check('fixture 3', solve(100, [('gzip', 70), ('br', 60)], 10), 'br')", "check('fixture 4', solve(100, [], 10), None)"]
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 | gzip | None | Failed |
| fixture 3 | br | br | Passed |
| fixture 4 | None | None | Passed |
| fixture 1 | None | None | Passed |
SHA-256 / a2346fe6bd9ceef5d4a2b9def164e747b13e1943b775c68d120bbc908baf2965
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(raw, candidates, overhead):
return min((c for c in candidates if c[1]+overhead < raw),key=lambda c:c[1],default=(None,))[0]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(100, [('gzip', 95)], 10), None)", "check('fixture 2', solve(100, [('gzip', 90)], 10), None)", "check('fixture 3', solve(100, [('gzip', 70), ('br', 60)], 10), 'br')", "check('fixture 4', solve(100, [], 10), None)"]
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 | None | None | Passed |
| fixture 3 | br | br | Passed |
| fixture 4 | None | None | Passed |
| fixture 1 | None | None | Passed |
SHA-256 / c96184505dde46ed85449b0c61edff00facdea60464abee6458947cc80ca60ab
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 2026-09-29T14:38:06.135016+00:00.
Case digest / 71bd2f952a5928ce51de6bb446d8fc18758994bb81c0e352177ed6f199a53d10