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FA-36731 / Tab interfaces / Open access

Per tab location history: history cap oldest eviction · case 01

The tab workspace reports an incorrect history cap oldest eviction.

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

ROOT CAUSE

The history cap oldest eviction decision uses (x['history'][:x['cursor']+1]+[x['new_location']])[:x['cap']] instead of (x['history'][:x['cursor']+1]+[x['new_location']])[-x['cap']:].

VERIFIED REPAIR

Use the stipulated workspace rule: (x['history'][:x['cursor']+1]+[x['new_location']])[-x['cap']:].

Unsuccessful approach: The partial repair x['history'][:x['cursor']+1]+[x['new_location']] still violates a workspace boundary or normal case.

Case contract

A document tab maintains location history independent of sibling views. Navigating after Back truncates its forward branch, caps history and restores exact cursor offsets.

Why this case matters

Offline tab/panel workspace behavior; no browser or desktop framework is emulated.

1 / The failure

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

N = 1
observations = []
def solve(x):
    r0 = x['history'][:x['cursor']+1]
    r1 = x['history'][:x['cursor']+1]+[x['new_location']]
    r2 = (x['history'][:x['cursor']+1]+[x['new_location']])[:x['cap']]
    r3 = max(0,x['cursor']-x['back_steps'])
    r4 = x['history'][max(0,x['cursor']-x['back_steps'])]
    r5 = x['sibling']
    return [r0,r1,r2,r3,r4,r5]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = {1: [({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 3, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 20, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 0, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 50], [10, 50], 0, 10, [3, 6]])], 2: [({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [10, 20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 3, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 100], [20, 30, 40, 100], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 40, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 40], [10, 20, 40], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 100], [10, 20, 100], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 0, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 100], [10, 100], 0, 10, [3, 6]])], 3: [({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 150], [10, 20, 150], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 3, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 150], [20, 30, 40, 150], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 150], [20, 150], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 60, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 60], [10, 20, 60], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 150], [10, 20, 150], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 0, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 150], [10, 150], 0, 10, [3, 6]])], 4: [({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 200], [10, 20, 200], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 3, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 200], [20, 30, 40, 200], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 200], [20, 200], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 80, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 80], [10, 20, 80], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 200], [10, 20, 200], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 0, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 200], [10, 200], 0, 10, [3, 6]])], 5: [({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 250], [10, 20, 250], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 3, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 250], [20, 30, 40, 250], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 250], [20, 250], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [10, 20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 250], [10, 20, 250], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 0, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 250], [10, 250], 0, 10, [3, 6]])]}
for i, (inputs, expected) in enumerate(fixtures[N]):
    check("workspace regression "+str(i), solve(inputs), expected)
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
workspace regression 0[[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]][[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]]Passed
workspace regression 1[[10, 20, 30, 40], [10, 20, 30, 40, 50], [10, 20, 30, 40], 2, 30, [3, 6]][[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]]Failed
workspace regression 2[[10, 20], [10, 20, 50], [10, 20], 0, 10, [3, 6]][[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]]Failed
workspace regression 3[[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]][[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]]Passed
workspace regression 4[[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]][[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]]Passed
workspace regression 5[[10], [10, 50], [10, 50], 0, 10, [3, 6]][[10], [10, 50], [10, 50], 0, 10, [3, 6]]Passed

SHA-256 / ad0aeee6fae2425b6a6c53cc4f1f7ceb73402bec85f9c8d44c1decee137b61bb

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(x):
    r0 = x['history'][:x['cursor']+1]
    r1 = x['history'][:x['cursor']+1]+[x['new_location']]
    r2 = x['history'][:x['cursor']+1]+[x['new_location']]
    r3 = max(0,x['cursor']-x['back_steps'])
    r4 = x['history'][max(0,x['cursor']-x['back_steps'])]
    r5 = x['sibling']
    return [r0,r1,r2,r3,r4,r5]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = {1: [({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 3, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 20, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 0, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 50], [10, 50], 0, 10, [3, 6]])], 2: [({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [10, 20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 3, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 100], [20, 30, 40, 100], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 40, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 40], [10, 20, 40], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 100], [10, 20, 100], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 0, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 100], [10, 100], 0, 10, [3, 6]])], 3: [({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 150], [10, 20, 150], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 3, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 150], [20, 30, 40, 150], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 150], [20, 150], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 60, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 60], [10, 20, 60], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 150], [10, 20, 150], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 0, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 150], [10, 150], 0, 10, [3, 6]])], 4: [({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 200], [10, 20, 200], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 3, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 200], [20, 30, 40, 200], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 200], [20, 200], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 80, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 80], [10, 20, 80], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 200], [10, 20, 200], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 0, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 200], [10, 200], 0, 10, [3, 6]])], 5: [({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 250], [10, 20, 250], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 3, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 250], [20, 30, 40, 250], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 250], [20, 250], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [10, 20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 250], [10, 20, 250], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 0, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 250], [10, 250], 0, 10, [3, 6]])]}
for i, (inputs, expected) in enumerate(fixtures[N]):
    check("workspace regression "+str(i), solve(inputs), expected)
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
workspace regression 0[[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]][[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]]Passed
workspace regression 1[[10, 20, 30, 40], [10, 20, 30, 40, 50], [10, 20, 30, 40, 50], 2, 30, [3, 6]][[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]]Failed
workspace regression 2[[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]][[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]]Failed
workspace regression 3[[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]][[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]]Passed
workspace regression 4[[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]][[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]]Passed
workspace regression 5[[10], [10, 50], [10, 50], 0, 10, [3, 6]][[10], [10, 50], [10, 50], 0, 10, [3, 6]]Passed

SHA-256 / 1fdfefdcd392a404645133b4575b297e1e6b070aee478ceedcd7b128200746d9

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    r0 = x['history'][:x['cursor']+1]
    r1 = x['history'][:x['cursor']+1]+[x['new_location']]
    r2 = (x['history'][:x['cursor']+1]+[x['new_location']])[-x['cap']:]
    r3 = max(0,x['cursor']-x['back_steps'])
    r4 = x['history'][max(0,x['cursor']-x['back_steps'])]
    r5 = x['sibling']
    return [r0,r1,r2,r3,r4,r5]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = {1: [({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 3, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 20, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 1, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40], 'cursor': 0, 'new_location': 50, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 50], [10, 50], 0, 10, [3, 6]])], 2: [({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [10, 20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 3, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 100], [20, 30, 40, 100], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 40, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 40], [10, 20, 40], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 100], [10, 20, 100], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0'], 'cursor': 0, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 100], [10, 100], 0, 10, [3, 6]])], 3: [({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 150], [10, 20, 150], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 3, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 150], [20, 30, 40, 150], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 150], [20, 150], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 60, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 60], [10, 20, 60], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 1, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 150], [10, 20, 150], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1'], 'cursor': 0, 'new_location': 150, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 150], [10, 150], 0, 10, [3, 6]])], 4: [({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 200], [10, 20, 200], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 3, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 200], [20, 30, 40, 200], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 200], [20, 200], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 80, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 80], [10, 20, 80], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 1, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 200], [10, 20, 200], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2'], 'cursor': 0, 'new_location': 200, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 200], [10, 200], 0, 10, [3, 6]])], 5: [({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 250], [10, 20, 250], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 3, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20, 30, 40], [10, 20, 30, 40, 250], [20, 30, 40, 250], 2, 30, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 2, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 250], [20, 250], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 100, 'cap': 4, 'sibling': [3, 6], 'back_steps': 1}, [[10, 20], [10, 20, 100], [10, 20, 100], 0, 10, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 1, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 0}, [[10, 20], [10, 20, 250], [10, 20, 250], 1, 20, [3, 6]]), ({'history': [10, 20, 30, 40, 'background0', 'background1', 'background2', 'background3'], 'cursor': 0, 'new_location': 250, 'cap': 4, 'sibling': [3, 6], 'back_steps': 3}, [[10], [10, 250], [10, 250], 0, 10, [3, 6]])]}
for i, (inputs, expected) in enumerate(fixtures[N]):
    check("workspace regression "+str(i), solve(inputs), expected)
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
workspace regression 0[[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]][[10, 20], [10, 20, 50], [10, 20, 50], 0, 10, [3, 6]]Passed
workspace regression 1[[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]][[10, 20, 30, 40], [10, 20, 30, 40, 50], [20, 30, 40, 50], 2, 30, [3, 6]]Passed
workspace regression 2[[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]][[10, 20], [10, 20, 50], [20, 50], 0, 10, [3, 6]]Passed
workspace regression 3[[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]][[10, 20], [10, 20, 20], [10, 20, 20], 0, 10, [3, 6]]Passed
workspace regression 4[[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]][[10, 20], [10, 20, 50], [10, 20, 50], 1, 20, [3, 6]]Passed
workspace regression 5[[10], [10, 50], [10, 50], 0, 10, [3, 6]][[10], [10, 50], [10, 50], 0, 10, [3, 6]]Passed

SHA-256 / 0d9f342ebf5e2871c6034404cac0d652aec1c84173151077b0a1564e64efb599

Verification & scope

Finite stipulated workspace snapshots only. Independent result fields describe observable obligations, not a full UI runtime. 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 2026-09-29T14:42:54.208657+00:00.

Case digest / c2c43154e46acbe37be0234bdcae4e8e8ad1a811cb35b69f2223ecaeb423a01f