FA-99701 / Chunk citation alignment / Open access

Merged chunk offsets ignore inserted separator lengths · case 01

Merged chunk offsets ignore inserted separator lengths.

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

ROOT CAUSE

Chunk starts are accumulated using content lengths alone.

THE FAILURE

Chunk starts are accumulated using content lengths alone.

Unsuccessful approach: Adding one separator per chunk also counts a nonexistent separator before the first chunk.

Case contract

Given chunk lengths and a constant separator length, return each chunk start in the joined text; no leading separator.

Why this case matters

A deterministic citation bookkeeping model isolates source attribution from rendering and retrieval.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(lengths, separator):
    starts=[]
    pos=0
    for length in lengths:
     starts.append(pos)
     pos+=length
    return starts
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('two chunks',solve([N,3],2),[0,N+2])
check('three chunks',solve([1,2,3],1),[0,2,5])
check('empty',solve([],4),[])
check('one chunk',solve([N],5),[0])
check('zero separator',solve([2,4],0),[0,2])
check('zero length chunk',solve([0,2],3),[0,3])
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
two chunks	`[0, 1]`	`[0, 3]`	Failed
three chunks	`[0, 1, 3]`	`[0, 2, 5]`	Failed
empty	`[]`	`[]`	Passed
one chunk	`[0]`	`[0]`	Passed
zero separator	`[0, 2]`	`[0, 2]`	Passed
zero length chunk	`[0, 0]`	`[0, 3]`	Failed

SHA-256 / e25e1f09e70df2c685f579aa1e43f5e15e0a81ded7ccc6ef5b45324f529077cb

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(lengths, separator):
    starts=[]
    pos=0
    for length in lengths:
     pos+=separator
     starts.append(pos)
     pos+=length
    return starts
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('two chunks',solve([N,3],2),[0,N+2])
check('three chunks',solve([1,2,3],1),[0,2,5])
check('empty',solve([],4),[])
check('one chunk',solve([N],5),[0])
check('zero separator',solve([2,4],0),[0,2])
check('zero length chunk',solve([0,2],3),[0,3])
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
two chunks	`[2, 5]`	`[0, 3]`	Failed
three chunks	`[1, 3, 6]`	`[0, 2, 5]`	Failed
empty	`[]`	`[]`	Passed
one chunk	`[5]`	`[0]`	Failed
zero separator	`[0, 2]`	`[0, 2]`	Passed
zero length chunk	`[3, 6]`	`[0, 3]`	Failed

SHA-256 / 7129b38fdb1ed2ee4d99850c4736dc34673256bc7708678ead73586b47d90b81

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

Inputs are small integer offsets and identifiers under the stated toy contract; this does not define a document format or production citation API. 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 2026-09-30T16:48:27.159076+00:00.

Case digest / d641ba27c7c654081453cba5c99698dcd261b734e3cf1ef07750ea8c31cf3785