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FA-100141 / Annotation span alignment / Open access

Insertion shifts spans at and after the insertion point · case 01

Insertion shifts spans at and after the insertion point.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Both endpoints use strict-after movement, so a boundary at the insertion point does not follow the inserted text.

THE FAILURE

Both endpoints use strict-after movement, so a boundary at the insertion point does not follow the inserted text.

Unsuccessful approach: Using right affinity for starts but strict-after movement for ends leaves spans ending exactly at the insertion point unshifted.

Case contract

For spans [start,end) and insertion [at,length), apply right affinity: endpoints at or after at shift by length; earlier endpoints stay fixed.

Why this case matters

A small offline annotation transformation keeps span coordinates explicit when text or token boundaries change.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(spans, at, length):
    return [[s+(length if s>at else 0), e+(length if e>at else 0)] for s,e in spans]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('strictly before', solve([[1,3]],4,N), [[1,3]])
check('strictly after', solve([[5,8]],4,N), [[5+N,8+N]])
check('at start follows inserted text', solve([[4,7]],4,N), [[4+N,7+N]])
check('at end follows inserted text', solve([[1,4]],4,N), [[1,4+N]])
check('empty span on insertion', solve([[4,4]],4,N), [[4+N,4+N]])
check('empty spans list', solve([],4,N), [])
check('zero length insertion', solve([[4,6]],4,0), [[4,6]])
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 fixtureActualExpectedOutcome
strictly before[[1, 3]][[1, 3]]Passed
strictly after[[6, 9]][[6, 9]]Passed
at start follows inserted text[[4, 8]][[5, 8]]Failed
at end follows inserted text[[1, 4]][[1, 5]]Failed
empty span on insertion[[4, 4]][[5, 5]]Failed
empty spans list[][]Passed
zero length insertion[[4, 6]][[4, 6]]Passed

SHA-256 / 5dd8ffaf366c3c6dfcd2742f1f34fc7eba8647822d14c417ccfa85806c5800ae

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(spans, at, length):
    return [[s+(length if s>=at else 0), e+(length if e>at else 0)] for s,e in spans]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('strictly before', solve([[1,3]],4,N), [[1,3]])
check('strictly after', solve([[5,8]],4,N), [[5+N,8+N]])
check('at start follows inserted text', solve([[4,7]],4,N), [[4+N,7+N]])
check('at end follows inserted text', solve([[1,4]],4,N), [[1,4+N]])
check('empty span on insertion', solve([[4,4]],4,N), [[4+N,4+N]])
check('empty spans list', solve([],4,N), [])
check('zero length insertion', solve([[4,6]],4,0), [[4,6]])
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 fixtureActualExpectedOutcome
strictly before[[1, 3]][[1, 3]]Passed
strictly after[[6, 9]][[6, 9]]Passed
at start follows inserted text[[5, 8]][[5, 8]]Passed
at end follows inserted text[[1, 4]][[1, 5]]Failed
empty span on insertion[[5, 4]][[5, 5]]Failed
empty spans list[][]Passed
zero length insertion[[4, 6]][[4, 6]]Passed

SHA-256 / 3b556edaf16a25c04b70dbd2d3fcfc33d06ae0f204696d9524b5c8cc0ccb0162

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 7 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.

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Verification & scope

Contracts use integer offsets, explicit edits, and supplied token boundaries; they do not define a tokenizer or production annotation format. 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 2026-09-30T16:48:32.171503+00:00.

Case digest / 9eae442fb0019c793c9b2441f30e68148f60c135010b0ae10819b360599472f8