FA-34506 / Notification interfaces / Open access
Swipe-to-dismiss notification feedback: snapback-finished from returning · case 01
The snapback-finished event leaves a notification in dismissed instead of resting.
ROOT CAUSE
Snapback completion discards the notification.
VERIFIED REPAIR
Commit the returning / snapback-finished transition to resting; preserve the other explicitly stipulated transitions.
Unsuccessful approach: Keeping drag styling leaves a stuck offset surface.
Case contract
Swipe-to-dismiss notification feedback is a bounded visual-notification workflow with mutable policy state {'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False}. Its default transition relation is {('resting', 'drag-start'): 'dragging', ('dragging', 'below-threshold-release'): 'returning', ('dragging', 'above-threshold-release'): 'committing', ('returning', 'snapback-finished'): 'resting', ('committing', 'dismiss-accepted'): 'exit-animating', ('committing', 'dismiss-rejected'): 'returning', ('exit-animating', 'animation-finished'): 'dismissed', ('dragging', 'pointer-cancel'): 'returning', ('exit-animating', 'reduced-motion-enabled'): 'dismissed', ('committing', 'second-pointer-down'): 'committing'}; domain inputs can suppress or redirect transitions and update policy fields, as specified in solve. Different-generation events are inert. Batches apply in order. Optional observe returns the selected policy field alongside the phase.
Why this case matters
Visual notification lifecycle ordering can leave an inbox or toast showing the wrong actionable state even when transport succeeds.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(initial, events, generation, payload=None, observe=None):
table = {('resting', 'drag-start'): 'dragging', ('dragging', 'below-threshold-release'): 'returning', ('dragging', 'above-threshold-release'): 'committing', ('returning', 'snapback-finished'): 'dismissed', ('committing', 'dismiss-accepted'): 'exit-animating', ('committing', 'dismiss-rejected'): 'returning', ('exit-animating', 'animation-finished'): 'dismissed', ('dragging', 'pointer-cancel'): 'returning', ('exit-animating', 'reduced-motion-enabled'): 'dismissed', ('committing', 'second-pointer-down'): 'committing'}
data = json.loads(json.dumps({'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False})) if payload is None else {**json.loads(json.dumps({'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False})), **json.loads(json.dumps(payload))}
state = initial
for delivery in events:
event, event_generation = delivery[:2]
arg = delivery[2] if len(delivery) > 2 else {}
if event_generation == generation:
previous = state
if event in ('below-threshold-release','above-threshold-release','pointer-cancel') and arg.get('pointer',data['pointer']) != data['pointer']: event = 'unknown-event'
if event in ('below-threshold-release','above-threshold-release') and 'offset' in arg:
data['offset'] = arg['offset']
event = 'above-threshold-release' if abs(data['offset']) >= data['threshold'] else 'below-threshold-release'
state = table.get((state, event), state)
if state == 'resting': data['offset'] = 0
if state == 'dismissed': data['removed'] = True
return {'phase': state, 'value': data[observe]} if observe else state
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('resting / drag-start', solve('resting', [('drag-start', N)], N), 'dragging')
check('dragging / below-threshold-release', solve('dragging', [('below-threshold-release', N)], N), 'returning')
check('dragging / above-threshold-release', solve('dragging', [('above-threshold-release', N)], N), 'committing')
check('returning / snapback-finished', solve('returning', [('snapback-finished', N)], N), 'resting')
check('committing / dismiss-accepted', solve('committing', [('dismiss-accepted', N)], N), 'exit-animating')
check('committing / dismiss-rejected', solve('committing', [('dismiss-rejected', N)], N), 'returning')
check('exit-animating / animation-finished', solve('exit-animating', [('animation-finished', N)], N), 'dismissed')
check('dragging / pointer-cancel', solve('dragging', [('pointer-cancel', N)], N), 'returning')
check('exit-animating / reduced-motion-enabled', solve('exit-animating', [('reduced-motion-enabled', N)], N), 'dismissed')
check('committing / second-pointer-down', solve('committing', [('second-pointer-down', N)], N), 'committing')
check('older notification incarnation', solve('resting', [('drag-start', N - 1)], N), 'resting')
check('future notification incarnation', solve('resting', [('drag-start', N + 1)], N), 'resting')
check('unknown event is inert', solve('resting', [('unknown-event', N)], N), 'resting')
check('empty delivery batch', solve('resting', [], N), 'resting')
check('N stale deliveries before current delivery', solve('resting', [('drag-start', N - 1)] * N + [('drag-start', N)], N), 'dragging')
check('trace drag-start then below-threshold-release', solve('resting', [('drag-start', N), ('below-threshold-release', N)], N), 'returning')
check('trace drag-start then above-threshold-release', solve('resting', [('drag-start', N), ('above-threshold-release', N)], N), 'committing')
check('trace drag-start then pointer-cancel', solve('resting', [('drag-start', N), ('pointer-cancel', N)], N), 'returning')
check('trace below-threshold-release then snapback-finished', solve('dragging', [('below-threshold-release', N), ('snapback-finished', N)], N), 'resting')
check('trace above-threshold-release then dismiss-accepted', solve('dragging', [('above-threshold-release', N), ('dismiss-accepted', N)], N), 'exit-animating')
check('trace above-threshold-release then dismiss-rejected', solve('dragging', [('above-threshold-release', N), ('dismiss-rejected', N)], N), 'returning')
check('trace above-threshold-release then second-pointer-down', solve('dragging', [('above-threshold-release', N), ('second-pointer-down', N)], N), 'committing')
check('trace snapback-finished then drag-start', solve('returning', [('snapback-finished', N), ('drag-start', N)], N), 'dragging')
check('trace dismiss-accepted then animation-finished', solve('committing', [('dismiss-accepted', N), ('animation-finished', N)], N), 'dismissed')
check('trace dismiss-accepted then reduced-motion-enabled', solve('committing', [('dismiss-accepted', N), ('reduced-motion-enabled', N)], N), 'dismissed')
check('trace dismiss-rejected then snapback-finished', solve('committing', [('dismiss-rejected', N), ('snapback-finished', N)], N), 'resting')
check('trace pointer-cancel then snapback-finished', solve('dragging', [('pointer-cancel', N), ('snapback-finished', N)], N), 'resting')
check('trace second-pointer-down then dismiss-accepted', solve('committing', [('second-pointer-down', N), ('dismiss-accepted', N)], N), 'exit-animating')
check('trace second-pointer-down then dismiss-rejected', solve('committing', [('second-pointer-down', N), ('dismiss-rejected', N)], N), 'returning')
check('trace second-pointer-down then second-pointer-down', solve('committing', [('second-pointer-down', N), ('second-pointer-down', N)], N), 'committing')
check('domain state regression 1: offset', solve('dragging', [('above-threshold-release', N, {'offset': 39})], N, {}, 'offset'), {'phase': 'returning', 'value': 39})
check('domain state regression 2: offset', solve('dragging', [('below-threshold-release', N, {'offset': -40})], N, {}, 'offset'), {'phase': 'committing', 'value': -40})
check('domain state regression 3: offset', solve('dragging', [('above-threshold-release', N, {'pointer': 6, 'offset': 90})], N, {}, 'offset'), {'phase': 'dragging', 'value': 0})
check('domain state regression 4: offset', solve('returning', [('snapback-finished', N, {})], N, {'offset': 25}, 'offset'), {'phase': 'resting', 'value': 0})
check('domain state regression 5: removed', solve('exit-animating', [('reduced-motion-enabled', N, {})], N, {}, 'removed'), {'phase': 'dismissed', 'value': True})
check('domain state regression 6: removed', solve('committing', [('dismiss-rejected', N, {})], N, {'offset': 50}, 'removed'), {'phase': 'returning', 'value': False})
check('domain state regression 7: offset', solve('resting', [('drag-start', N, {}), ('above-threshold-release', N, {'offset': 39}), ('snapback-finished', N, {})], N, {}, 'offset'), {'phase': 'resting', 'value': 0})
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 |
|---|---|---|---|
| resting / drag-start | dragging | dragging | Passed |
| dragging / below-threshold-release | returning | returning | Passed |
| dragging / above-threshold-release | committing | committing | Passed |
| returning / snapback-finished | dismissed | resting | Failed |
| committing / dismiss-accepted | exit-animating | exit-animating | Passed |
| committing / dismiss-rejected | returning | returning | Passed |
| exit-animating / animation-finished | dismissed | dismissed | Passed |
| dragging / pointer-cancel | returning | returning | Passed |
| exit-animating / reduced-motion-enabled | dismissed | dismissed | Passed |
| committing / second-pointer-down | committing | committing | Passed |
| older notification incarnation | resting | resting | Passed |
| future notification incarnation | resting | resting | Passed |
| unknown event is inert | resting | resting | Passed |
| empty delivery batch | resting | resting | Passed |
| N stale deliveries before current delivery | dragging | dragging | Passed |
| trace drag-start then below-threshold-release | returning | returning | Passed |
| trace drag-start then above-threshold-release | committing | committing | Passed |
| trace drag-start then pointer-cancel | returning | returning | Passed |
| trace below-threshold-release then snapback-finished | dismissed | resting | Failed |
| trace above-threshold-release then dismiss-accepted | exit-animating | exit-animating | Passed |
| trace above-threshold-release then dismiss-rejected | returning | returning | Passed |
| trace above-threshold-release then second-pointer-down | committing | committing | Passed |
| trace snapback-finished then drag-start | dismissed | dragging | Failed |
| trace dismiss-accepted then animation-finished | dismissed | dismissed | Passed |
| trace dismiss-accepted then reduced-motion-enabled | dismissed | dismissed | Passed |
| trace dismiss-rejected then snapback-finished | dismissed | resting | Failed |
| trace pointer-cancel then snapback-finished | dismissed | resting | Failed |
| trace second-pointer-down then dismiss-accepted | exit-animating | exit-animating | Passed |
| trace second-pointer-down then dismiss-rejected | returning | returning | Passed |
| trace second-pointer-down then second-pointer-down | committing | committing | Passed |
| domain state regression 1: offset | {'phase': 'returning', 'value': 39} | {'phase': 'returning', 'value': 39} | Passed |
| domain state regression 2: offset | {'phase': 'committing', 'value': -40} | {'phase': 'committing', 'value': -40} | Passed |
| domain state regression 3: offset | {'phase': 'dragging', 'value': 0} | {'phase': 'dragging', 'value': 0} | Passed |
| domain state regression 4: offset | {'phase': 'dismissed', 'value': 25} | {'phase': 'resting', 'value': 0} | Failed |
| domain state regression 5: removed | {'phase': 'dismissed', 'value': True} | {'phase': 'dismissed', 'value': True} | Passed |
| domain state regression 6: removed | {'phase': 'returning', 'value': False} | {'phase': 'returning', 'value': False} | Passed |
| domain state regression 7: offset | {'phase': 'dismissed', 'value': 39} | {'phase': 'resting', 'value': 0} | Failed |
SHA-256 / 77923bc6d5d70cb1cb3559cfdf44a6b59bce8a00a6f44b6a7b01ed3c5ce877b8
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(initial, events, generation, payload=None, observe=None):
table = {('resting', 'drag-start'): 'dragging', ('dragging', 'below-threshold-release'): 'returning', ('dragging', 'above-threshold-release'): 'committing', ('returning', 'snapback-finished'): 'dragging', ('committing', 'dismiss-accepted'): 'exit-animating', ('committing', 'dismiss-rejected'): 'returning', ('exit-animating', 'animation-finished'): 'dismissed', ('dragging', 'pointer-cancel'): 'returning', ('exit-animating', 'reduced-motion-enabled'): 'dismissed', ('committing', 'second-pointer-down'): 'committing'}
data = json.loads(json.dumps({'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False})) if payload is None else {**json.loads(json.dumps({'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False})), **json.loads(json.dumps(payload))}
state = initial
for delivery in events:
event, event_generation = delivery[:2]
arg = delivery[2] if len(delivery) > 2 else {}
if event_generation == generation:
previous = state
if event in ('below-threshold-release','above-threshold-release','pointer-cancel') and arg.get('pointer',data['pointer']) != data['pointer']: event = 'unknown-event'
if event in ('below-threshold-release','above-threshold-release') and 'offset' in arg:
data['offset'] = arg['offset']
event = 'above-threshold-release' if abs(data['offset']) >= data['threshold'] else 'below-threshold-release'
state = table.get((state, event), state)
if state == 'resting': data['offset'] = 0
if state == 'dismissed': data['removed'] = True
return {'phase': state, 'value': data[observe]} if observe else state
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('resting / drag-start', solve('resting', [('drag-start', N)], N), 'dragging')
check('dragging / below-threshold-release', solve('dragging', [('below-threshold-release', N)], N), 'returning')
check('dragging / above-threshold-release', solve('dragging', [('above-threshold-release', N)], N), 'committing')
check('returning / snapback-finished', solve('returning', [('snapback-finished', N)], N), 'resting')
check('committing / dismiss-accepted', solve('committing', [('dismiss-accepted', N)], N), 'exit-animating')
check('committing / dismiss-rejected', solve('committing', [('dismiss-rejected', N)], N), 'returning')
check('exit-animating / animation-finished', solve('exit-animating', [('animation-finished', N)], N), 'dismissed')
check('dragging / pointer-cancel', solve('dragging', [('pointer-cancel', N)], N), 'returning')
check('exit-animating / reduced-motion-enabled', solve('exit-animating', [('reduced-motion-enabled', N)], N), 'dismissed')
check('committing / second-pointer-down', solve('committing', [('second-pointer-down', N)], N), 'committing')
check('older notification incarnation', solve('resting', [('drag-start', N - 1)], N), 'resting')
check('future notification incarnation', solve('resting', [('drag-start', N + 1)], N), 'resting')
check('unknown event is inert', solve('resting', [('unknown-event', N)], N), 'resting')
check('empty delivery batch', solve('resting', [], N), 'resting')
check('N stale deliveries before current delivery', solve('resting', [('drag-start', N - 1)] * N + [('drag-start', N)], N), 'dragging')
check('trace drag-start then below-threshold-release', solve('resting', [('drag-start', N), ('below-threshold-release', N)], N), 'returning')
check('trace drag-start then above-threshold-release', solve('resting', [('drag-start', N), ('above-threshold-release', N)], N), 'committing')
check('trace drag-start then pointer-cancel', solve('resting', [('drag-start', N), ('pointer-cancel', N)], N), 'returning')
check('trace below-threshold-release then snapback-finished', solve('dragging', [('below-threshold-release', N), ('snapback-finished', N)], N), 'resting')
check('trace above-threshold-release then dismiss-accepted', solve('dragging', [('above-threshold-release', N), ('dismiss-accepted', N)], N), 'exit-animating')
check('trace above-threshold-release then dismiss-rejected', solve('dragging', [('above-threshold-release', N), ('dismiss-rejected', N)], N), 'returning')
check('trace above-threshold-release then second-pointer-down', solve('dragging', [('above-threshold-release', N), ('second-pointer-down', N)], N), 'committing')
check('trace snapback-finished then drag-start', solve('returning', [('snapback-finished', N), ('drag-start', N)], N), 'dragging')
check('trace dismiss-accepted then animation-finished', solve('committing', [('dismiss-accepted', N), ('animation-finished', N)], N), 'dismissed')
check('trace dismiss-accepted then reduced-motion-enabled', solve('committing', [('dismiss-accepted', N), ('reduced-motion-enabled', N)], N), 'dismissed')
check('trace dismiss-rejected then snapback-finished', solve('committing', [('dismiss-rejected', N), ('snapback-finished', N)], N), 'resting')
check('trace pointer-cancel then snapback-finished', solve('dragging', [('pointer-cancel', N), ('snapback-finished', N)], N), 'resting')
check('trace second-pointer-down then dismiss-accepted', solve('committing', [('second-pointer-down', N), ('dismiss-accepted', N)], N), 'exit-animating')
check('trace second-pointer-down then dismiss-rejected', solve('committing', [('second-pointer-down', N), ('dismiss-rejected', N)], N), 'returning')
check('trace second-pointer-down then second-pointer-down', solve('committing', [('second-pointer-down', N), ('second-pointer-down', N)], N), 'committing')
check('domain state regression 1: offset', solve('dragging', [('above-threshold-release', N, {'offset': 39})], N, {}, 'offset'), {'phase': 'returning', 'value': 39})
check('domain state regression 2: offset', solve('dragging', [('below-threshold-release', N, {'offset': -40})], N, {}, 'offset'), {'phase': 'committing', 'value': -40})
check('domain state regression 3: offset', solve('dragging', [('above-threshold-release', N, {'pointer': 6, 'offset': 90})], N, {}, 'offset'), {'phase': 'dragging', 'value': 0})
check('domain state regression 4: offset', solve('returning', [('snapback-finished', N, {})], N, {'offset': 25}, 'offset'), {'phase': 'resting', 'value': 0})
check('domain state regression 5: removed', solve('exit-animating', [('reduced-motion-enabled', N, {})], N, {}, 'removed'), {'phase': 'dismissed', 'value': True})
check('domain state regression 6: removed', solve('committing', [('dismiss-rejected', N, {})], N, {'offset': 50}, 'removed'), {'phase': 'returning', 'value': False})
check('domain state regression 7: offset', solve('resting', [('drag-start', N, {}), ('above-threshold-release', N, {'offset': 39}), ('snapback-finished', N, {})], N, {}, 'offset'), {'phase': 'resting', 'value': 0})
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 |
|---|---|---|---|
| resting / drag-start | dragging | dragging | Passed |
| dragging / below-threshold-release | returning | returning | Passed |
| dragging / above-threshold-release | committing | committing | Passed |
| returning / snapback-finished | dragging | resting | Failed |
| committing / dismiss-accepted | exit-animating | exit-animating | Passed |
| committing / dismiss-rejected | returning | returning | Passed |
| exit-animating / animation-finished | dismissed | dismissed | Passed |
| dragging / pointer-cancel | returning | returning | Passed |
| exit-animating / reduced-motion-enabled | dismissed | dismissed | Passed |
| committing / second-pointer-down | committing | committing | Passed |
| older notification incarnation | resting | resting | Passed |
| future notification incarnation | resting | resting | Passed |
| unknown event is inert | resting | resting | Passed |
| empty delivery batch | resting | resting | Passed |
| N stale deliveries before current delivery | dragging | dragging | Passed |
| trace drag-start then below-threshold-release | returning | returning | Passed |
| trace drag-start then above-threshold-release | committing | committing | Passed |
| trace drag-start then pointer-cancel | returning | returning | Passed |
| trace below-threshold-release then snapback-finished | dragging | resting | Failed |
| trace above-threshold-release then dismiss-accepted | exit-animating | exit-animating | Passed |
| trace above-threshold-release then dismiss-rejected | returning | returning | Passed |
| trace above-threshold-release then second-pointer-down | committing | committing | Passed |
| trace snapback-finished then drag-start | dragging | dragging | Passed |
| trace dismiss-accepted then animation-finished | dismissed | dismissed | Passed |
| trace dismiss-accepted then reduced-motion-enabled | dismissed | dismissed | Passed |
| trace dismiss-rejected then snapback-finished | dragging | resting | Failed |
| trace pointer-cancel then snapback-finished | dragging | resting | Failed |
| trace second-pointer-down then dismiss-accepted | exit-animating | exit-animating | Passed |
| trace second-pointer-down then dismiss-rejected | returning | returning | Passed |
| trace second-pointer-down then second-pointer-down | committing | committing | Passed |
| domain state regression 1: offset | {'phase': 'returning', 'value': 39} | {'phase': 'returning', 'value': 39} | Passed |
| domain state regression 2: offset | {'phase': 'committing', 'value': -40} | {'phase': 'committing', 'value': -40} | Passed |
| domain state regression 3: offset | {'phase': 'dragging', 'value': 0} | {'phase': 'dragging', 'value': 0} | Passed |
| domain state regression 4: offset | {'phase': 'dragging', 'value': 25} | {'phase': 'resting', 'value': 0} | Failed |
| domain state regression 5: removed | {'phase': 'dismissed', 'value': True} | {'phase': 'dismissed', 'value': True} | Passed |
| domain state regression 6: removed | {'phase': 'returning', 'value': False} | {'phase': 'returning', 'value': False} | Passed |
| domain state regression 7: offset | {'phase': 'dragging', 'value': 39} | {'phase': 'resting', 'value': 0} | Failed |
SHA-256 / 33f4865cc5776346ce3de812344fd2f6aa075d9a99d5401aec89a05e72cd60fd
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(initial, events, generation, payload=None, observe=None):
table = {('resting', 'drag-start'): 'dragging', ('dragging', 'below-threshold-release'): 'returning', ('dragging', 'above-threshold-release'): 'committing', ('returning', 'snapback-finished'): 'resting', ('committing', 'dismiss-accepted'): 'exit-animating', ('committing', 'dismiss-rejected'): 'returning', ('exit-animating', 'animation-finished'): 'dismissed', ('dragging', 'pointer-cancel'): 'returning', ('exit-animating', 'reduced-motion-enabled'): 'dismissed', ('committing', 'second-pointer-down'): 'committing'}
data = json.loads(json.dumps({'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False})) if payload is None else {**json.loads(json.dumps({'offset': 0, 'threshold': 40, 'pointer': 7, 'removed': False})), **json.loads(json.dumps(payload))}
state = initial
for delivery in events:
event, event_generation = delivery[:2]
arg = delivery[2] if len(delivery) > 2 else {}
if event_generation == generation:
previous = state
if event in ('below-threshold-release','above-threshold-release','pointer-cancel') and arg.get('pointer',data['pointer']) != data['pointer']: event = 'unknown-event'
if event in ('below-threshold-release','above-threshold-release') and 'offset' in arg:
data['offset'] = arg['offset']
event = 'above-threshold-release' if abs(data['offset']) >= data['threshold'] else 'below-threshold-release'
state = table.get((state, event), state)
if state == 'resting': data['offset'] = 0
if state == 'dismissed': data['removed'] = True
return {'phase': state, 'value': data[observe]} if observe else state
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('resting / drag-start', solve('resting', [('drag-start', N)], N), 'dragging')
check('dragging / below-threshold-release', solve('dragging', [('below-threshold-release', N)], N), 'returning')
check('dragging / above-threshold-release', solve('dragging', [('above-threshold-release', N)], N), 'committing')
check('returning / snapback-finished', solve('returning', [('snapback-finished', N)], N), 'resting')
check('committing / dismiss-accepted', solve('committing', [('dismiss-accepted', N)], N), 'exit-animating')
check('committing / dismiss-rejected', solve('committing', [('dismiss-rejected', N)], N), 'returning')
check('exit-animating / animation-finished', solve('exit-animating', [('animation-finished', N)], N), 'dismissed')
check('dragging / pointer-cancel', solve('dragging', [('pointer-cancel', N)], N), 'returning')
check('exit-animating / reduced-motion-enabled', solve('exit-animating', [('reduced-motion-enabled', N)], N), 'dismissed')
check('committing / second-pointer-down', solve('committing', [('second-pointer-down', N)], N), 'committing')
check('older notification incarnation', solve('resting', [('drag-start', N - 1)], N), 'resting')
check('future notification incarnation', solve('resting', [('drag-start', N + 1)], N), 'resting')
check('unknown event is inert', solve('resting', [('unknown-event', N)], N), 'resting')
check('empty delivery batch', solve('resting', [], N), 'resting')
check('N stale deliveries before current delivery', solve('resting', [('drag-start', N - 1)] * N + [('drag-start', N)], N), 'dragging')
check('trace drag-start then below-threshold-release', solve('resting', [('drag-start', N), ('below-threshold-release', N)], N), 'returning')
check('trace drag-start then above-threshold-release', solve('resting', [('drag-start', N), ('above-threshold-release', N)], N), 'committing')
check('trace drag-start then pointer-cancel', solve('resting', [('drag-start', N), ('pointer-cancel', N)], N), 'returning')
check('trace below-threshold-release then snapback-finished', solve('dragging', [('below-threshold-release', N), ('snapback-finished', N)], N), 'resting')
check('trace above-threshold-release then dismiss-accepted', solve('dragging', [('above-threshold-release', N), ('dismiss-accepted', N)], N), 'exit-animating')
check('trace above-threshold-release then dismiss-rejected', solve('dragging', [('above-threshold-release', N), ('dismiss-rejected', N)], N), 'returning')
check('trace above-threshold-release then second-pointer-down', solve('dragging', [('above-threshold-release', N), ('second-pointer-down', N)], N), 'committing')
check('trace snapback-finished then drag-start', solve('returning', [('snapback-finished', N), ('drag-start', N)], N), 'dragging')
check('trace dismiss-accepted then animation-finished', solve('committing', [('dismiss-accepted', N), ('animation-finished', N)], N), 'dismissed')
check('trace dismiss-accepted then reduced-motion-enabled', solve('committing', [('dismiss-accepted', N), ('reduced-motion-enabled', N)], N), 'dismissed')
check('trace dismiss-rejected then snapback-finished', solve('committing', [('dismiss-rejected', N), ('snapback-finished', N)], N), 'resting')
check('trace pointer-cancel then snapback-finished', solve('dragging', [('pointer-cancel', N), ('snapback-finished', N)], N), 'resting')
check('trace second-pointer-down then dismiss-accepted', solve('committing', [('second-pointer-down', N), ('dismiss-accepted', N)], N), 'exit-animating')
check('trace second-pointer-down then dismiss-rejected', solve('committing', [('second-pointer-down', N), ('dismiss-rejected', N)], N), 'returning')
check('trace second-pointer-down then second-pointer-down', solve('committing', [('second-pointer-down', N), ('second-pointer-down', N)], N), 'committing')
check('domain state regression 1: offset', solve('dragging', [('above-threshold-release', N, {'offset': 39})], N, {}, 'offset'), {'phase': 'returning', 'value': 39})
check('domain state regression 2: offset', solve('dragging', [('below-threshold-release', N, {'offset': -40})], N, {}, 'offset'), {'phase': 'committing', 'value': -40})
check('domain state regression 3: offset', solve('dragging', [('above-threshold-release', N, {'pointer': 6, 'offset': 90})], N, {}, 'offset'), {'phase': 'dragging', 'value': 0})
check('domain state regression 4: offset', solve('returning', [('snapback-finished', N, {})], N, {'offset': 25}, 'offset'), {'phase': 'resting', 'value': 0})
check('domain state regression 5: removed', solve('exit-animating', [('reduced-motion-enabled', N, {})], N, {}, 'removed'), {'phase': 'dismissed', 'value': True})
check('domain state regression 6: removed', solve('committing', [('dismiss-rejected', N, {})], N, {'offset': 50}, 'removed'), {'phase': 'returning', 'value': False})
check('domain state regression 7: offset', solve('resting', [('drag-start', N, {}), ('above-threshold-release', N, {'offset': 39}), ('snapback-finished', N, {})], N, {}, 'offset'), {'phase': 'resting', 'value': 0})
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 |
|---|---|---|---|
| resting / drag-start | dragging | dragging | Passed |
| dragging / below-threshold-release | returning | returning | Passed |
| dragging / above-threshold-release | committing | committing | Passed |
| returning / snapback-finished | resting | resting | Passed |
| committing / dismiss-accepted | exit-animating | exit-animating | Passed |
| committing / dismiss-rejected | returning | returning | Passed |
| exit-animating / animation-finished | dismissed | dismissed | Passed |
| dragging / pointer-cancel | returning | returning | Passed |
| exit-animating / reduced-motion-enabled | dismissed | dismissed | Passed |
| committing / second-pointer-down | committing | committing | Passed |
| older notification incarnation | resting | resting | Passed |
| future notification incarnation | resting | resting | Passed |
| unknown event is inert | resting | resting | Passed |
| empty delivery batch | resting | resting | Passed |
| N stale deliveries before current delivery | dragging | dragging | Passed |
| trace drag-start then below-threshold-release | returning | returning | Passed |
| trace drag-start then above-threshold-release | committing | committing | Passed |
| trace drag-start then pointer-cancel | returning | returning | Passed |
| trace below-threshold-release then snapback-finished | resting | resting | Passed |
| trace above-threshold-release then dismiss-accepted | exit-animating | exit-animating | Passed |
| trace above-threshold-release then dismiss-rejected | returning | returning | Passed |
| trace above-threshold-release then second-pointer-down | committing | committing | Passed |
| trace snapback-finished then drag-start | dragging | dragging | Passed |
| trace dismiss-accepted then animation-finished | dismissed | dismissed | Passed |
| trace dismiss-accepted then reduced-motion-enabled | dismissed | dismissed | Passed |
| trace dismiss-rejected then snapback-finished | resting | resting | Passed |
| trace pointer-cancel then snapback-finished | resting | resting | Passed |
| trace second-pointer-down then dismiss-accepted | exit-animating | exit-animating | Passed |
| trace second-pointer-down then dismiss-rejected | returning | returning | Passed |
| trace second-pointer-down then second-pointer-down | committing | committing | Passed |
| domain state regression 1: offset | {'phase': 'returning', 'value': 39} | {'phase': 'returning', 'value': 39} | Passed |
| domain state regression 2: offset | {'phase': 'committing', 'value': -40} | {'phase': 'committing', 'value': -40} | Passed |
| domain state regression 3: offset | {'phase': 'dragging', 'value': 0} | {'phase': 'dragging', 'value': 0} | Passed |
| domain state regression 4: offset | {'phase': 'resting', 'value': 0} | {'phase': 'resting', 'value': 0} | Passed |
| domain state regression 5: removed | {'phase': 'dismissed', 'value': True} | {'phase': 'dismissed', 'value': True} | Passed |
| domain state regression 6: removed | {'phase': 'returning', 'value': False} | {'phase': 'returning', 'value': False} | Passed |
| domain state regression 7: offset | {'phase': 'resting', 'value': 0} | {'phase': 'resting', 'value': 0} | Passed |
SHA-256 / 68ed9877dd1261f73a256868fed53c5b39b31097a897ea030720873f879c3cc3
Verification & scope
Stipulated single-notification state and policy model only. Event delivery and acknowledgements are explicit test inputs. No DOM, accessibility announcements, live timers, networking, actual rendering, or production-platform conformance is simulated. 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 2026-09-29T14:42:32.622244+00:00.
Case digest / 2477a0a2fd65ed71c4c6805e6cfcb50be7da443147d9077bcb914b7d6746ae26