{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp09_archetype_breadth150_20260804","cell_id":"constraint_propagation_and_decoupling__computer_science","arm":"BREADTH_PROBE_ONE_SHOT","candidate_id":"constraint_propagation_and_decoupling__computer_science__P1","proposal_index":1,"version":0,"title":"Constraint-Derived Migration Cells for Shared-Schema Deployments","problem":"During a zero-downtime database-schema migration, several services, deployed versions, schema states, data backfills, traffic-routing states, and rollback targets must remain mutually compatible. Teams commonly plan each service change separately or coordinate the entire migration as one runbook without propagating compatibility and ordering constraints. Locally valid steps can therefore create a combined state in which a live binary cannot read the schema, concurrent writers produce incompatible data, or the declared rollback version can no longer resume safely.","actors":["Release engineer coordinating the migration","Service owners supplying version and data-contract requirements","Database engineer responsible for schema changes and backfills","Site-reliability engineer responsible for availability and rollback safeguards","Deployment orchestrator executing only approved steps"],"observable_state":"The migration plan contains service-level steps that pass their individual checks, yet a timeline or staging rehearsal exposes intervals with incompatible reader/writer versions, unsafe rollback targets, or conflicting backfill and schema-lock requirements. The runbook also serializes changes to unrelated tables because residual dependencies have not been distinguished from assumed global coupling.","consequence":"A migration can be halted late, prolong a release freeze, require emergency coordination, corrupt the intended data representation, or cause an availability incident when separately prepared changes are combined.","affected_objective":"Produce an auditable deployment sequence that preserves live-version readability, write compatibility, data invariants, availability limits, and a declared rollback path while allowing genuinely independent migration work to proceed separately.","intervention":"For one migration, construct a constraint network whose variables are deployed service versions, schema versions, reader and writer contracts, backfill states, traffic-routing states, lock budgets, and rollback targets. Propagate hard compatibility and ordering constraints to a fixed point, recording excluded or forced states. Apply cut-set or separator analysis to the residual dependency graph and create migration cells only where no unrecorded shared table, writer, lock budget, or rollback dependency crosses the boundary. Owners prepare each cell under explicit boundary conditions; before execution, a recomposition consistency test checks the combined sequence and permitted interleavings against the original compatibility and rollback invariants.","structural_mapping":[{"archetype_element":"Constraint Network Model","domain_realization":"A bipartite graph linking service-version and migration-state variables to read, write, ordering, lock, availability, and rollback constraints."},{"archetype_element":"Implication propagation","domain_realization":"Compatibility rules propagate forward and backward to eliminate deployment orders, force expand-before-deploy or backfill-before-contract steps, and narrow which versions may coexist."},{"archetype_element":"Derived Implication Register","domain_realization":"An auditable record of every forced ordering, excluded coexistence state, assumed contract, and minimal conflicting constraint set."},{"archetype_element":"Redundancy and infeasibility pruning","domain_realization":"Equivalent deployment orders that yield the same observable schema and service compatibility state are represented once, while incompatible intermediate states are removed."},{"archetype_element":"Coupling Boundary Map","domain_realization":"Residual edges identify shared tables, writers, lock budgets, traffic gates, or rollback targets that still couple otherwise separate migration work."},{"archetype_element":"Decoupled Subproblem Partition","domain_realization":"Migration cells contain locally solvable service-and-schema changes with explicit entry states, exit states, and cross-cell commitments."},{"archetype_element":"Consistency and Recomposition Check","domain_realization":"The proposed cell outputs are combined and checked so every allowed global intermediate state retains reader, writer, data, availability, and rollback compatibility."},{"archetype_element":"Propagation Stop Condition","domain_realization":"Propagation stops when no variable domain narrows further, a contradiction is explained, or all proposed cell boundaries have explicit residual dependencies."}],"mechanism_mapping":[{"mechanism_slug":"constraint_dependency_matrix","role":"Makes each service version's read, write, ordering, locking, and rollback dependencies on schema states explicit.","counterfactual_removal":"Without the matrix, hidden shared-state dependencies can survive into the partition and apparent independence is not justified."},{"mechanism_slug":"domain_reduction_pass","role":"Removes impossible coexistence states and forces prerequisite migration phases before teams plan local sequences.","counterfactual_removal":"Without domain reduction, teams continue planning and reviewing intermediate states that existing compatibility rules already make infeasible."},{"mechanism_slug":"cut_set_or_separator_analysis","role":"Finds boundaries where migration work can be separated after propagated dependencies are removed, while retaining shared tables and rollback gates as interface conditions.","counterfactual_removal":"Without separator analysis, the process either preserves unnecessary global serialization or splits work according to team ownership rather than residual coupling."},{"mechanism_slug":"recomposition_consistency_test","role":"Checks the combined cell sequence and permitted interleavings against the original global invariants before approval.","counterfactual_removal":"Without recomposition, locally valid cells can still produce an unsafe global schema or deployment state."}],"causal_chain":["Unpropagated compatibility, ordering, capacity, and rollback constraints make every service change appear globally coupled while concealing some unsafe combinations.","Encoding those constraints against explicit service-version and migration-state variables exposes their propagation paths.","Fixed-point propagation forces prerequisite steps, narrows coexistence windows, and removes infeasible intermediate states.","The reduced dependency graph distinguishes genuine shared-state couplings from dependencies already discharged by forced steps or boundary conditions.","Separator analysis yields migration cells with explicit interfaces instead of organization-based work packages.","Service owners solve and review their cells within the propagated domains.","Recomposition testing rejects combined sequences or interleavings that violate an original compatibility, availability, data, or rollback invariant.","Only a recomposed plan that passes the checks is presented to the existing migration authority for execution approval."],"baseline":"A manually authored expand-migrate-contract runbook coordinated in a shared document, with service owners checking their own compatibility and a staging rehearsal used to discover cross-service conflicts. Work is either serialized conservatively or divided by service ownership.","nearest_rivals":["A deployment dependency DAG that enforces explicitly entered precedence edges but does not derive additional bounds or justify new partitions through propagation.","A schema registry or contract test suite that validates compatibility at a selected state but does not reduce the multi-stage plan or locate residual coupling boundaries.","A deployment orchestrator with health gates and automatic rollback that reacts during execution rather than proving coexistence and rollback feasibility across the proposed state sequence.","A model checker that explores the global migration state space without using propagated constraints to produce owner-addressable, recomposable migration cells."],"remaining_contrastive_claim":"The candidate's distinguishing claim is procedural: derive forced and impossible migration states from the full constraint network before choosing work boundaries, then accept local plans only after a global recomposition check. Merely documenting dependencies, validating individual contracts, or partitioning by service ownership does not instantiate that chain.","authority_safety":{"decision_authority":"The existing release-change authority—typically the release engineer, database owner, and designated reliability approver—retains authority to classify constraints, approve boundaries, relax requirements, and authorize execution.","authorized_first_step":"Run a read-only replay on one completed, non-emergency migration using archived manifests, contracts, and the final runbook; generate advisory implications and partitions without controlling a deployment.","excluded_actions":["Automatically alter application code, migration scripts, schemas, or production data","Automatically approve, schedule, pause, or roll back a deployment","Relax a hard compatibility, data-integrity, availability, or rollback constraint without named human approval","Infer undocumented production dependencies and treat them as verified facts","Expose credentials, production records, or sensitive data values in the constraint register"],"halt_rollback":"Halt the replay if required contracts cannot be represented, derived implications lack traceable source constraints, or the model contradicts an observed safe state without explanation. Discard the advisory partition and retain the original runbook and approval process; the first step makes no production change requiring operational rollback."},"negative_tests":{"strongest_counterevidence":"For representative migrations, stable service interfaces already define safe independent boundaries, and ordinary contract tests plus the runbook identify the same ordering and conflicts without propagation or recomposition modeling.","problem_falsifier":"Inspection of the selected migration shows that each service touches disjoint schema objects, no deployed versions overlap, no shared writer, lock, traffic, or rollback constraint crosses services, and locally validated steps compose directly; the alleged constraint-coupled problem is absent.","intervention_falsifier":"The replay either fails to derive every known critical cross-service dependency, proposes a cell boundary crossed by a verified hard dependency, or produces no auditable reduction in feasible states or coordination scope beyond the baseline runbook.","risks":["An incomplete constraint inventory can create false independence and conceal a production dependency.","Stale service contracts or deployment manifests can make propagated conclusions invalid.","Treating preferences as hard constraints can over-serialize the migration; treating safety constraints as soft can admit unsafe states.","State-space growth can make recomposition checking impractical unless the modeled scope is bounded.","Opaque solver output can reduce reviewer trust or hide an incorrect rule.","Teams may mistake an advisory cell boundary for execution authorization.","The model may omit operational phenomena such as replication lag, long transactions, or external consumers that couple otherwise separate schema changes."]},"next_evidence_step":"Within a single two-hour shadow session, replay one completed migration involving at most six services, three schema transitions, and one rollback target. Build the constraint matrix from archived artifacts, run one fixed-point domain-reduction pass, propose separators, and test the recorded final sequence plus two owner-proposed alternative interleavings. Record whether the method reproduces every known dependency, identifies any unsupported serialization, supplies traceable conflict explanations, and preserves all declared invariants. Do not connect the prototype to deployment or production systems.","prior_art_status":"UNSEARCHED","diversity_from_prior_proposals":"Not assessed against other proposals because runtime isolation forbids inspecting them; this candidate independently realizes the supplied archetype in multi-service database-migration planning rather than relying on prior experiment context.","revision_record":{"parent_version":null,"progress_targets_addressed":[],"conceptual_changes":["Initial one-shot candidate mapping constraint propagation and justified decoupling to shared-schema migration planning."],"operational_changes":["Defines a read-only historical replay, bounded scope, explicit authority, stop conditions, and no production control."],"evidence_changes":["Sets a single bounded replay with observable dependency-recall, partition-safety, explanation, and invariant-preservation checks."],"claim_changes":["Limits the claim to a contrastive procedural structure and makes no novelty, prevalence, demand, or effect-size claim."]}}