{"id":"state-machines-instantiate-forward-only-monotonicity","text":"One-directional state machines across domains (window lifecycles, alert evaluators) are concrete instantiations of the codebase's forward-only/monotonicity constraint: the architectural primitive that discourages regression and supports progress manifests at the domain level as largely irreversible state progressions, though partial regressions (e.g., PENDING→OK in alerting) show the constraint is applied with domain-specific flexibility rather than as a strict universal rule.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["one-directional-state-machines-span-domains","forward-only-and-monotonicity-are-a-single-constraint"],"outlist":[],"label":"connects the domain-level observation (state machines span domains) with the architectural principle (forward-only and monotonicity are unified), showing the specific mechanism by which the abstract constraint surfaces in implementations"}],"dependents":["state-machines-enforce-temporal-gap-containment"],"metadata":{"last_reviewed":"2026-06-06T06:26:57","review_result":"invalid"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"state-machines-instantiate-forward-only-monotonicity","truth_value":"IN","reason":"SL justification valid","antecedents":["one-directional-state-machines-span-domains","forward-only-and-monotonicity-are-a-single-constraint"],"label":"connects the domain-level observation (state machines span domains) with the architectural principle (forward-only and monotonicity are unified), showing the specific mechanism by which the abstract constraint surfaces in implementations"},{"node":"one-directional-state-machines-span-domains","truth_value":"IN","reason":"SL justification valid","antecedents":["window-lifecycle-one-directional","metrics-alert-state-machine-four-states"],"label":"Both stream windows and alert evaluation use irreversible state machines to prevent regression"},{"node":"window-lifecycle-one-directional","truth_value":"IN","reason":"premise"},{"node":"metrics-alert-state-machine-four-states","truth_value":"IN","reason":"premise"},{"node":"forward-only-and-monotonicity-are-a-single-constraint","truth_value":"IN","reason":"SL justification valid","antecedents":["forward-only-design-prevents-regression-and-maximizes-progress","monotonicity-is-the-universal-ordering-primitive"],"label":"Forward-only processing and monotonic ordering are temporal vs ordinal views of the same unidirectional constraint"},{"node":"forward-only-design-prevents-regression-and-maximizes-progress","truth_value":"IN","reason":"SL justification valid","antecedents":["state-ratchets-prevent-regression-across-domains","pipeline-processing-maximizes-forward-progress"],"label":"State ratchets and forward-progress pipelines are complementary mechanisms — ratchets prevent regression in stateful systems, pipelines prevent regression in dataflow systems"},{"node":"state-ratchets-prevent-regression-across-domains","truth_value":"IN","reason":"SL justification valid","antecedents":["chat-monotonic-read-progress","watermark-finalization-is-irreversible"],"label":"chat read cursors are monotonic (never re-mark as unread), aggregation windows follow OPEN→CLOSED→FINALIZED with no reversal — both are state ratchets that make backwards movement structurally impossible"},{"node":"chat-monotonic-read-progress","truth_value":"IN","reason":"SL justification valid","antecedents":["chat-dual-ordering-sequence-and-lamport","chat-read-cursors-monotonic"],"label":"Sequence-number ordering + monotonic cursors create an irreversible read-progress guarantee"},{"node":"chat-dual-ordering-sequence-and-lamport","truth_value":"IN","reason":"premise"},{"node":"chat-read-cursors-monotonic","truth_value":"IN","reason":"premise"},{"node":"watermark-finalization-is-irreversible","truth_value":"IN","reason":"SL justification valid","antecedents":["watermark-drives-finalization","window-lifecycle-one-directional","no-window-merging-or-retraction"],"label":"Three properties compose into hard irreversibility: watermark-only trigger + one-way lifecycle + no retraction"},{"node":"watermark-drives-finalization","truth_value":"IN","reason":"premise"},{"node":"no-window-merging-or-retraction","truth_value":"IN","reason":"premise"},{"node":"pipeline-processing-maximizes-forward-progress","truth_value":"IN","reason":"SL justification valid","antecedents":["video-pipeline-maximizes-useful-work-on-failure","watermark-finalization-is-irreversible"],"label":"Video pipeline (branch-independent failure containment) and stream processing (irreversible finalization) both embody the same forward-only processing principle"},{"node":"video-pipeline-maximizes-useful-work-on-failure","truth_value":"IN","reason":"SL justification valid","antecedents":["dag-failure-cascade","youtube-pipeline-dag-structure"],"label":"DAG topology + selective cascade means a thumbnail failure doesn't block a successful transcode"},{"node":"dag-failure-cascade","truth_value":"IN","reason":"premise"},{"node":"youtube-pipeline-dag-structure","truth_value":"IN","reason":"premise"},{"node":"monotonicity-is-the-universal-ordering-primitive","truth_value":"IN","reason":"SL justification valid","antecedents":["id-generators-preserve-monotonic-order","state-ratchets-prevent-regression-across-domains"],"label":"ID generation, messaging cursors, and stream windows all share the non-decreasing-value invariant as their correctness foundation"},{"node":"id-generators-preserve-monotonic-order","truth_value":"IN","reason":"SL justification valid","antecedents":["snowflake-sequence-max-4096-per-ms","ulid-monotonic-within-millisecond","stock-exchange-trade-counter-global","all-stateful-generators-thread-safe"],"label":"Three generators use different monotonicity mechanisms; all share thread-safety via locks — a cross-system pattern of ordered-ID-generation-under-concurrency"},{"node":"snowflake-sequence-max-4096-per-ms","truth_value":"IN","reason":"premise"},{"node":"ulid-monotonic-within-millisecond","truth_value":"IN","reason":"premise"},{"node":"stock-exchange-trade-counter-global","truth_value":"IN","reason":"premise"},{"node":"all-stateful-generators-thread-safe","truth_value":"IN","reason":"premise"}]}}