FA-33011 / Menu interactions / Open access

Overflow popup drops the first overflowed menu command · case 01

Overflow popup drops the first overflowed menu command.

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

ROOT CAUSE

The overflow-menu model applies `p['items'][:p['fit']]` at its suffix operation instead of the stipulated transformation.

VERIFIED REPAIR

Apply `p['items'][p['fit']:]` at suffix.

Unsuccessful approach: The attempted repair `p['items'][p['fit']+1:]` still violates the suffix oracle.

Case contract

A menu overflow container reserves its own trigger, preserves complete groups, and restores source order when room returns.

Why this case matters

Cascading and context menus require coherent command and session state as content changes.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
import unicodedata
N = 1
observations = []
def solve(action, p):
    if action == 'reserve-trigger':
        return p['capacity']-p['trigger']
    if action == 'prefix-fit':
        return next((i for i in range(len(p['widths'])+1) if sum(p['widths'][:i+1])>p['capacity']),len(p['widths']))
    if action == 'suffix':
        return p['items'][:p['fit']]
    if action == 'group-atomic':
        return [g for g in p['groups'] if g['width']<=p['remaining']]
    if action == 'restore':
        return sorted(p,key=lambda x:x['source'])
    if action == 'trigger-visible':
        return bool(p['overflow'])
    return {'error': 'unsupported menu operation'}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('reserve-trigger contract', solve('reserve-trigger', {'capacity':N+10,'trigger':3}), N+7)
check('prefix-fit contract', solve('prefix-fit', {'widths':[N+1,N+1,N+1],'capacity':2*(N+1)}), 2)
check('suffix contract', solve('suffix', {'items':list(range(N+4)),'fit':2}), list(range(2,N+4)))
check('group-atomic contract', solve('group-atomic', {'groups':[{'width':N+2,'id':'a'},{'width':N+3,'id':'b'}],'remaining':N+2}), [{'width':N+2,'id':'a'}])
check('restore contract', solve('restore', [{'source':2,'label':'a'},{'source':N-N,'label':'z'}]), [{'source':0,'label':'z'},{'source':2,'label':'a'}])
check('trigger-visible contract', solve('trigger-visible', {'overflow':[],'capacity':N,'main':list(range(N))}), False)
check('unknown operation', solve('unknown', {}), {'error': 'unsupported menu operation'})
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
reserve-trigger contract	`8`	`8`	Passed
prefix-fit contract	`2`	`2`	Passed
suffix contract	`[0, 1]`	`[2, 3, 4]`	Failed
group-atomic contract	`[{'id': 'a', 'width': 3}]`	`[{'id': 'a', 'width': 3}]`	Passed
restore contract	`[{'label': 'z', 'source': 0}, {'label': 'a', 'source': 2}]`	`[{'label': 'z', 'source': 0}, {'label': 'a', 'source': 2}]`	Passed
trigger-visible contract	`False`	`False`	Passed
unknown operation	`{'error': 'unsupported menu operation'}`	`{'error': 'unsupported menu operation'}`	Passed

SHA-256 / d7cae79d373244a5a3717fbed2e25275290c4d3e5810a296853f2f1b0ad7410a

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
import unicodedata
N = 1
observations = []
def solve(action, p):
    if action == 'reserve-trigger':
        return p['capacity']-p['trigger']
    if action == 'prefix-fit':
        return next((i for i in range(len(p['widths'])+1) if sum(p['widths'][:i+1])>p['capacity']),len(p['widths']))
    if action == 'suffix':
        return p['items'][p['fit']+1:]
    if action == 'group-atomic':
        return [g for g in p['groups'] if g['width']<=p['remaining']]
    if action == 'restore':
        return sorted(p,key=lambda x:x['source'])
    if action == 'trigger-visible':
        return bool(p['overflow'])
    return {'error': 'unsupported menu operation'}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('reserve-trigger contract', solve('reserve-trigger', {'capacity':N+10,'trigger':3}), N+7)
check('prefix-fit contract', solve('prefix-fit', {'widths':[N+1,N+1,N+1],'capacity':2*(N+1)}), 2)
check('suffix contract', solve('suffix', {'items':list(range(N+4)),'fit':2}), list(range(2,N+4)))
check('group-atomic contract', solve('group-atomic', {'groups':[{'width':N+2,'id':'a'},{'width':N+3,'id':'b'}],'remaining':N+2}), [{'width':N+2,'id':'a'}])
check('restore contract', solve('restore', [{'source':2,'label':'a'},{'source':N-N,'label':'z'}]), [{'source':0,'label':'z'},{'source':2,'label':'a'}])
check('trigger-visible contract', solve('trigger-visible', {'overflow':[],'capacity':N,'main':list(range(N))}), False)
check('unknown operation', solve('unknown', {}), {'error': 'unsupported menu operation'})
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
reserve-trigger contract	`8`	`8`	Passed
prefix-fit contract	`2`	`2`	Passed
suffix contract	`[3, 4]`	`[2, 3, 4]`	Failed
group-atomic contract	`[{'id': 'a', 'width': 3}]`	`[{'id': 'a', 'width': 3}]`	Passed
restore contract	`[{'label': 'z', 'source': 0}, {'label': 'a', 'source': 2}]`	`[{'label': 'z', 'source': 0}, {'label': 'a', 'source': 2}]`	Passed
trigger-visible contract	`False`	`False`	Passed
unknown operation	`{'error': 'unsupported menu operation'}`	`{'error': 'unsupported menu operation'}`	Passed

SHA-256 / b1daee57a4e4a21f9e8a6a9338797ef5e5656e7a2fa8f9e37e34855fb436b6ed

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
import unicodedata
N = 1
observations = []
def solve(action, p):
    if action == 'reserve-trigger':
        return p['capacity']-p['trigger']
    if action == 'prefix-fit':
        return next((i for i in range(len(p['widths'])+1) if sum(p['widths'][:i+1])>p['capacity']),len(p['widths']))
    if action == 'suffix':
        return p['items'][p['fit']:]
    if action == 'group-atomic':
        return [g for g in p['groups'] if g['width']<=p['remaining']]
    if action == 'restore':
        return sorted(p,key=lambda x:x['source'])
    if action == 'trigger-visible':
        return bool(p['overflow'])
    return {'error': 'unsupported menu operation'}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('reserve-trigger contract', solve('reserve-trigger', {'capacity':N+10,'trigger':3}), N+7)
check('prefix-fit contract', solve('prefix-fit', {'widths':[N+1,N+1,N+1],'capacity':2*(N+1)}), 2)
check('suffix contract', solve('suffix', {'items':list(range(N+4)),'fit':2}), list(range(2,N+4)))
check('group-atomic contract', solve('group-atomic', {'groups':[{'width':N+2,'id':'a'},{'width':N+3,'id':'b'}],'remaining':N+2}), [{'width':N+2,'id':'a'}])
check('restore contract', solve('restore', [{'source':2,'label':'a'},{'source':N-N,'label':'z'}]), [{'source':0,'label':'z'},{'source':2,'label':'a'}])
check('trigger-visible contract', solve('trigger-visible', {'overflow':[],'capacity':N,'main':list(range(N))}), False)
check('unknown operation', solve('unknown', {}), {'error': 'unsupported menu operation'})
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
reserve-trigger contract	`8`	`8`	Passed
prefix-fit contract	`2`	`2`	Passed
suffix contract	`[2, 3, 4]`	`[2, 3, 4]`	Passed
group-atomic contract	`[{'id': 'a', 'width': 3}]`	`[{'id': 'a', 'width': 3}]`	Passed
restore contract	`[{'label': 'z', 'source': 0}, {'label': 'a', 'source': 2}]`	`[{'label': 'z', 'source': 0}, {'label': 'a', 'source': 2}]`	Passed
trigger-visible contract	`False`	`False`	Passed
unknown operation	`{'error': 'unsupported menu operation'}`	`{'error': 'unsupported menu operation'}`	Passed

SHA-256 / 67a96186ab1c75343719c34406eae59dbf9a088bfe25933eab78774fe3d44424

Verification & scope

Offline supplied-valid-payload model; excludes DOM, keyboard, focus, selection, announcements and browser conformance. 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 2026-09-29T14:42:18.040103+00:00.

Case digest / 4ede6c1013ae70ca27e0cf6c5703dabada1acbc9f10ba63b583449dcce15284b