FA-5316 / Python evaluation / Open access

Chained comparison evaluation: Changes the first strict comparison into an inclusive one · case 01

Changes the first strict comparison into an inclusive one and changes the required Python-language result.

Verified by executionVariant 1 · 5 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Changes the first strict comparison into an inclusive one. The executable reproducer isolates this operation from the rest of the contract.

THE FAILURE

Changes the first strict comparison into an inclusive one. The executable reproducer isolates this operation from the rest of the contract.

Unsuccessful approach: The alternative still fails because it changes the second strict comparison into an inclusive one.

Case contract

Evaluate lhs() < middle() < rhs(). Evaluate the middle expression once, evaluate each operand left-to-right, and skip the final expression when the first comparison fails. Both inequalities are strict. Inputs use the finite Python types shown in the fixtures. An error string denotes the specified caught exception, not an unhandled process failure.

Why this case matters

Runs Python standard-library language operations in a deterministic local reproducer. Literal expected answers are authored independently. Related defects share an evaluation group to avoid benchmark split leakage.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(left, mid, right):
    trace=[]
    def lhs(): trace.append('left'); return left
    def middle(): trace.append('middle'); return mid
    def rhs(): trace.append('right'); return right
    result=lhs() <= middle() < rhs()
    return [result,trace]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('increasing triple', solve(1, 2, 3), [True, ['left', 'middle', 'right']])
check('first comparison fails', solve(3, 2, 9), [False, ['left', 'middle']])
check('equal first operands', solve(2, 2, 3), [False, ['left', 'middle']])
check('equal last operands', solve(1, 2, 2), [False, ['left', 'middle', 'right']])
check('second comparison fails', solve(1, 3, 2), [False, ['left', 'middle', 'right']])
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
increasing triple	`[True, ['left', 'middle', 'right']]`	`[True, ['left', 'middle', 'right']]`	Passed
first comparison fails	`[False, ['left', 'middle']]`	`[False, ['left', 'middle']]`	Passed
equal first operands	`[True, ['left', 'middle', 'right']]`	`[False, ['left', 'middle']]`	Failed
equal last operands	`[False, ['left', 'middle', 'right']]`	`[False, ['left', 'middle', 'right']]`	Passed
second comparison fails	`[False, ['left', 'middle', 'right']]`	`[False, ['left', 'middle', 'right']]`	Passed

SHA-256 / bc851304bb1fd113daa46551ac26ccbb85d2770cca61c0c4aa990f6c7664dab5

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(left, mid, right):
    trace=[]
    def lhs(): trace.append('left'); return left
    def middle(): trace.append('middle'); return mid
    def rhs(): trace.append('right'); return right
    result=lhs() < middle() <= rhs()
    return [result,trace]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('increasing triple', solve(1, 2, 3), [True, ['left', 'middle', 'right']])
check('first comparison fails', solve(3, 2, 9), [False, ['left', 'middle']])
check('equal first operands', solve(2, 2, 3), [False, ['left', 'middle']])
check('equal last operands', solve(1, 2, 2), [False, ['left', 'middle', 'right']])
check('second comparison fails', solve(1, 3, 2), [False, ['left', 'middle', 'right']])
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
increasing triple	`[True, ['left', 'middle', 'right']]`	`[True, ['left', 'middle', 'right']]`	Passed
first comparison fails	`[False, ['left', 'middle']]`	`[False, ['left', 'middle']]`	Passed
equal first operands	`[False, ['left', 'middle']]`	`[False, ['left', 'middle']]`	Passed
equal last operands	`[True, ['left', 'middle', 'right']]`	`[False, ['left', 'middle', 'right']]`	Failed
second comparison fails	`[False, ['left', 'middle', 'right']]`	`[False, ['left', 'middle', 'right']]`	Passed

SHA-256 / e168ac4037682f37827b4ba0c93a306ad88f09d8e7a77bacc2692b86ac494cf5

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 5 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

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 2026-09-29T14:37:48.295671+00:00.

Case digest / ade67a006e1be55b332c0c5e20a84ff1bff3086aa9fcaff831672091cb4c9466