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Switch starts the new inner before disposing the old one · case 05

Switch starts the new inner before disposing the old one; the returned lifecycle plan violates the stated transition contract.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

Plan switch-to-latest observer ownership. A new outer value replaces the active inner and advances an inner generation. Late values from the replaced generation are suppressed. Outer completion waits for the current inner, while an inner completion alone does not close a live outer. An error closes both. Dispose the old inner before starting the replacement, even if it emitted no value. Completion considers only active inner records belonging to the current generation; stale active records and current inactive records do not block it. Inputs are finite state snapshots, including transitional and stale states; output fields are the exact independent actions/metadata defined by the corrected expression table. Numeric fixture capacities and counts vary with N. Field definitions, each independently computed from the input snapshot: replace = s['outer_value'] and s['inner_active']; generation = s['generation']+int(s['outer_value']); accept = s['event_generation']==s['generation'] and s['inner_active'] and not s['cancel'] and s['error'] is None; outer_complete = s['outer_done'] and not any(active for generation,active in s['inner_records'] if generation==s['generation']); inner_complete = s['inner_done'] and s['outer_done']; start = s['outer_value'] and not s['outer_done'] and not s['cancel'] and s['error'] is None; transition_order = ['dispose','start'] if s['outer_value'] and s['inner_active'] else (['start'] if s['outer_value'] else []); active_after_done = s['inner_active'] and not(s['inner_done'] and s['event_generation']==s['generation']); dispose_outer = s['error'] is not None or s['cancel']; late_value = s['event_generation']!=s['generation']

Why this case matters

Observer implementations need to preserve this state while subscriptions enter, execute, and leave their lifecycle.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
transition 0	`{"accept": false, "active_after_done": true, "dispose_outer": true, "generation": 11, "inner_complete": false, "late_value": false, "outer_complete": true, "replace": true, "start": false, "transition_order": ["start", "dispose"]}`	`{"accept": false, "active_after_done": true, "dispose_outer": true, "generation": 11, "inner_complete": false, "late_value": false, "outer_complete": true, "replace": true, "start": false, "transition_order": ["dispose", "start"]}`	Failed

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