FA-26431 / HTTP ranges / Open access
Body rewriting removes source validators from range responses · case 01
Body rewriting removes source validators from range responses.
ROOT CAUSE
The transformation-invalidates-validator decision uses return source_tag.
VERIFIED REPAIR
Apply the bounded decision exactly: return derived_tag if transformed else source_tag
Unsuccessful approach: The partial repair uses return derived_tag or source_tag if transformed else source_tag, which still violates the stated contract.
Case contract
Return derived tag after transformation, including None for unavailable derived validators; unchanged responses retain source tag.
Why this case matters
Range responses combine representation identity, conditional requests, framing, and partial-object state.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(transformed, source_tag, derived_tag):
return source_tag
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('transformation-invalidates-validator fixture 0', solve(True,"s"+str(N),None), None)
check('transformation-invalidates-validator fixture 1', solve(True,"s","d"+str(N)), "d"+str(N))
check('transformation-invalidates-validator fixture 2', solve(False,"s","d"), "s")
check('transformation-invalidates-validator fixture 3', solve(False,None,"d"), None)
check('transformation-invalidates-validator fixture 4', solve(True,"s",""), "")
check('transformation-invalidates-validator fixture 5', solve(True,None,"d"), "d")
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 |
|---|---|---|---|
| transformation-invalidates-validator fixture 0 | s1 | None | Failed |
| transformation-invalidates-validator fixture 1 | s | d1 | Failed |
| transformation-invalidates-validator fixture 2 | s | s | Passed |
| transformation-invalidates-validator fixture 3 | None | None | Passed |
| transformation-invalidates-validator fixture 4 | s | | Failed |
| transformation-invalidates-validator fixture 5 | None | d | Failed |
SHA-256 / 9d3e0545d7c8c49beb68063b42a1f62077cca6ee5419ec4f2a2f5f78dd415f3f
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(transformed, source_tag, derived_tag):
return derived_tag or source_tag if transformed else source_tag
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('transformation-invalidates-validator fixture 0', solve(True,"s"+str(N),None), None)
check('transformation-invalidates-validator fixture 1', solve(True,"s","d"+str(N)), "d"+str(N))
check('transformation-invalidates-validator fixture 2', solve(False,"s","d"), "s")
check('transformation-invalidates-validator fixture 3', solve(False,None,"d"), None)
check('transformation-invalidates-validator fixture 4', solve(True,"s",""), "")
check('transformation-invalidates-validator fixture 5', solve(True,None,"d"), "d")
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 |
|---|---|---|---|
| transformation-invalidates-validator fixture 0 | s1 | None | Failed |
| transformation-invalidates-validator fixture 1 | d1 | d1 | Passed |
| transformation-invalidates-validator fixture 2 | s | s | Passed |
| transformation-invalidates-validator fixture 3 | None | None | Passed |
| transformation-invalidates-validator fixture 4 | s | | Failed |
| transformation-invalidates-validator fixture 5 | d | d | Passed |
SHA-256 / a7e6b2d183286d784b9b7004545aaf550a0cac335dacd74ab08cf7e2d9839e94
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(transformed, source_tag, derived_tag):
return derived_tag if transformed else source_tag
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('transformation-invalidates-validator fixture 0', solve(True,"s"+str(N),None), None)
check('transformation-invalidates-validator fixture 1', solve(True,"s","d"+str(N)), "d"+str(N))
check('transformation-invalidates-validator fixture 2', solve(False,"s","d"), "s")
check('transformation-invalidates-validator fixture 3', solve(False,None,"d"), None)
check('transformation-invalidates-validator fixture 4', solve(True,"s",""), "")
check('transformation-invalidates-validator fixture 5', solve(True,None,"d"), "d")
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 |
|---|---|---|---|
| transformation-invalidates-validator fixture 0 | None | None | Passed |
| transformation-invalidates-validator fixture 1 | d1 | d1 | Passed |
| transformation-invalidates-validator fixture 2 | s | s | Passed |
| transformation-invalidates-validator fixture 3 | None | None | Passed |
| transformation-invalidates-validator fixture 4 | | | Passed |
| transformation-invalidates-validator fixture 5 | d | d | Passed |
SHA-256 / 68669552c5998072b7afda8112419cdba438d7715a1de4d03160348aafde213b
Verification & scope
Deterministic simplified range service, with stipulated local policies and already parsed trusted inputs; not a complete HTTP implementation. 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 2026-09-29T14:41:15.945417+00:00.
Case digest / b7755320901ed5460c8ec66c39133f04bbdf82de8edf06c50b9f32a86fd89abf