FA-99201 / Checkpoint tensor mapping / Open access

Checkpoint mapping: requested axis permutation is ignored · case 01

requested axis permutation is ignored.

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

ROOT CAUSE

A valid permutation is checked but ignored when producing the mapped shape.

THE FAILURE

A valid permutation is checked but ignored when producing the mapped shape.

Unsuccessful approach: Sorting the permutation discards its requested axis order.

Case contract

Return shape with dimensions reordered by a valid permutation; invalid permutations return [].

Why this case matters

A bounded offline model of checkpoint tensor bookkeeping in a training workflow.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(shape, permutation):
    return list(reversed(shape)) if sorted(permutation)==list(range(len(shape))) else []
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('swap', solve(*([3, 2, 3], [1, 0, 2])), [2, 3, 3])
check('identity', solve(*([3, 2], [0, 1])), [3, 2])
check('reverse', solve(*([1, 2, 3], [2, 1, 0])), [3, 2, 1])
check('empty', solve(*([], [])), [])
check('duplicate', solve(*([3, 2], [0, 0])), [])
check('out of range', solve(*([3], [1])), [])
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
swap	`[3, 2, 3]`	`[2, 3, 3]`	Failed
identity	`[2, 3]`	`[3, 2]`	Failed
reverse	`[3, 2, 1]`	`[3, 2, 1]`	Passed
empty	`[]`	`[]`	Passed
duplicate	`[]`	`[]`	Passed
out of range	`[]`	`[]`	Passed

SHA-256 / 2351956513038277607d280a888644a3b3683a2d3e8fa71ff1b8ade1b762652d

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(shape, permutation):
    return [shape[i] for i in sorted(permutation)] if sorted(permutation)==list(range(len(shape))) else []
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('swap', solve(*([3, 2, 3], [1, 0, 2])), [2, 3, 3])
check('identity', solve(*([3, 2], [0, 1])), [3, 2])
check('reverse', solve(*([1, 2, 3], [2, 1, 0])), [3, 2, 1])
check('empty', solve(*([], [])), [])
check('duplicate', solve(*([3, 2], [0, 0])), [])
check('out of range', solve(*([3], [1])), [])
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
swap	`[3, 2, 3]`	`[2, 3, 3]`	Failed
identity	`[3, 2]`	`[3, 2]`	Passed
reverse	`[1, 2, 3]`	`[3, 2, 1]`	Failed
empty	`[]`	`[]`	Passed
duplicate	`[]`	`[]`	Passed
out of range	`[]`	`[]`	Passed

SHA-256 / 19e414a99882983c1e7ca46b5229f5529d026fe8a714c9cce2b77f465ce8b84d

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.

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Verification & scope

Inputs are already decoded Python values; this toy contract makes no claim about a framework, file format, or production checkpoint. 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 2026-09-30T16:48:21.700866+00:00.

Case digest / 900fc6307285cf6bb5d441093e33f6665c5eb2acc4be2ad06dedf2733ee28904