FA-26781 / HTTP ranges / Open access

Confirmed shorter complete representations truncate stale local suffix bytes · case 01

Confirmed shorter complete representations truncate stale local suffix bytes.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The resume-total-shrink-truncate decision uses return local.

THE FAILURE

The resume-total-shrink-truncate decision uses return local.

Unsuccessful approach: The partial repair uses return local[:confirmed_total] if confirmed_total else local, which still violates the stated contract.

Case contract

Return local prefix up to confirmed total; local buffers shorter than total remain as-is. This operation follows successful revision replacement.

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(local, confirmed_total):
    return local
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('resume-total-shrink-truncate fixture 0', solve("abc"*N,N), ("abc"*N)[:N])
check('resume-total-shrink-truncate fixture 1', solve("abc",0), "")
check('resume-total-shrink-truncate fixture 2', solve("abc",3), "abc")
check('resume-total-shrink-truncate fixture 3', solve("abc",5), "abc")
check('resume-total-shrink-truncate fixture 4', solve("",0), "")
check('resume-total-shrink-truncate fixture 5', solve("abcd",2), "ab")
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
resume-total-shrink-truncate fixture 0	`abc`	`a`	Failed
resume-total-shrink-truncate fixture 1	`abc`		Failed
resume-total-shrink-truncate fixture 2	`abc`	`abc`	Passed
resume-total-shrink-truncate fixture 3	`abc`	`abc`	Passed
resume-total-shrink-truncate fixture 4			Passed
resume-total-shrink-truncate fixture 5	`abcd`	`ab`	Failed

SHA-256 / 817b8de6200df918c6ff82e7f7bc1550a1e74a5f2a2f34b29acf86a2efbd17b0

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(local, confirmed_total):
    return local[:confirmed_total] if confirmed_total else local
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('resume-total-shrink-truncate fixture 0', solve("abc"*N,N), ("abc"*N)[:N])
check('resume-total-shrink-truncate fixture 1', solve("abc",0), "")
check('resume-total-shrink-truncate fixture 2', solve("abc",3), "abc")
check('resume-total-shrink-truncate fixture 3', solve("abc",5), "abc")
check('resume-total-shrink-truncate fixture 4', solve("",0), "")
check('resume-total-shrink-truncate fixture 5', solve("abcd",2), "ab")
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
resume-total-shrink-truncate fixture 0	`a`	`a`	Passed
resume-total-shrink-truncate fixture 1	`abc`		Failed
resume-total-shrink-truncate fixture 2	`abc`	`abc`	Passed
resume-total-shrink-truncate fixture 3	`abc`	`abc`	Passed
resume-total-shrink-truncate fixture 4			Passed
resume-total-shrink-truncate fixture 5	`ab`	`ab`	Passed

SHA-256 / edeae6d606e478f7bea28d3333cb60974d24c3fb54d257af40e19fd5489930e8

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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 2026-09-29T14:41:19.031412+00:00.

Case digest / b08ea8fca547c3fb897a07203a9a0d5491fb8002a27b3a2087af1d908eea40ed