FA-41748 / Listener lifecycle / Member archive

A throwing observer callback skips resource cleanup · case 03

A throwing observer callback skips resource cleanup; the returned lifecycle plan violates the stated transition contract.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Plan callback failure handling. Recoverable callback errors are collected and sibling callbacks continue unless fail-fast was selected. Fatal failures stop immediately. Cleanup always runs for acquired callback resources. Report an unhandled error once; a configured error listener consumes a recoverable error. A callback return value remains distinct from an exception. 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: continue = s['error']!='fatal' and not(s['error'] is not None and s['failfast']); cleanup = s['acquired'] and not s['cleanup_done']; report = s['error'] is not None and not s['reported'] and (not s['handler'] or s['error']=='fatal'); collected = list(s['errors'])+([s['error']] if s['error'] is not None else []); handler_call = s['handler'] and s['error']=='recoverable'; value = s['result'] if s['error'] is None else None; remaining = s['siblings'] if s['error']=='fatal' or (s['error'] is not None and s['failfast']) else 0; active = s['active'] and s['error']!='fatal'; handled = s['handler'] and s['error']=='recoverable' and not s['failfast']; fatal = s['error']=='fatal'

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	`{"active": true, "cleanup": false, "collected": ["earlier", "recoverable"], "continue": false, "fatal": false, "handled": false, "handler_call": true, "remaining": 9, "report": false, "value": null}`	`{"active": true, "cleanup": true, "collected": ["earlier", "recoverable"], "continue": false, "fatal": false, "handled": false, "handler_call": true, "remaining": 9, "report": false, "value": null}`	Failed

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