{"id":"changemanager-resolves-observer-liability-via-pattern-composition","text":"ChangeManager demonstrates that Observer's unexpected-updates liability can be mitigated through pattern composition (Observer+Mediator+Singleton) rather than application-specific safeguards, showing that the GoF catalog contains self-healing compositions where one pattern's liability is structurally addressed by composing with others.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["changemanager-mediator-observer-composition","gof-observer-unexpected-updates-liability","gof-changemanager-mediator-singleton"],"outlist":[],"label":"ChangeManager is a concrete example of liability-resolving pattern composition — the unexpected-updates problem from observer interdependencies is exactly what DAGChangeManager's mediating role prevents"}],"dependents":["liability-mitigation-makes-event-architecture-self-repairing","liability-mitigation-via-pattern-composition-is-catalog-architectural-property"],"metadata":{"source_type":"derived","review_result":"unnecessary"},"created_at":"2026-06-18T04:39:57+00:00","updated_at":"2026-06-18T06:15:08+00:00","reviewed_at":"2026-06-18T06:15:08+00:00","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"changemanager-resolves-observer-liability-via-pattern-composition","truth_value":"IN","reason":"SL justification valid","antecedents":["changemanager-mediator-observer-composition","gof-observer-unexpected-updates-liability","gof-changemanager-mediator-singleton"],"label":"ChangeManager is a concrete example of liability-resolving pattern composition — the unexpected-updates problem from observer interdependencies is exactly what DAGChangeManager's mediating role prevents"},{"node":"changemanager-mediator-observer-composition","truth_value":"IN","reason":"SL justification valid","antecedents":["gof-changemanager-mediator-singleton","observer-mediator-distribution-centralization-tradeoff"],"label":"ChangeManager is a concrete case where the abstract Observer-Mediator tradeoff is resolved by composition rather than selection — depth-2 from base + depth-1"},{"node":"gof-changemanager-mediator-singleton","truth_value":"IN","reason":"premise"},{"node":"observer-mediator-distribution-centralization-tradeoff","truth_value":"IN","reason":"SL justification valid","antecedents":["mediator-centralizes-observer-distributes","observers-more-reusable-than-mediators","gof-observer-unexpected-updates-liability","gof-mediator-centralizes-control-tradeoff"],"label":"Two base beliefs on the relationship + one liability each combine into a unified architectural tradeoff"},{"node":"mediator-centralizes-observer-distributes","truth_value":"IN","reason":"premise"},{"node":"observers-more-reusable-than-mediators","truth_value":"IN","reason":"premise"},{"node":"gof-observer-unexpected-updates-liability","truth_value":"IN","reason":"premise"},{"node":"gof-mediator-centralizes-control-tradeoff","truth_value":"IN","reason":"premise"}]}}