Changelog

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All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Entries for unreleased work are not written here directly. Each issue drops a fragment in changelog.d/; the fragments are assembled into a version section at release. See that README for the format and for when a change warrants an entry at all.

[0.11.0] 2026-09-08

Feature release: a durably stepped run can now report itself as it goes. StatifierPersistence.Driver.new/3 takes an after_step: callback, fired after every step the driver takes on a caller's behalf - a durable subchart child's own steps and the parent's step on the answer path alike - so a host can trace, project or checkpoint from one seam instead of wrapping each entry point. Alongside it, StatifierPersistence.Testing.StorageConformance no longer writes from a setup, so an adapter's own setup runs first.

Added

  • StatifierPersistence.Driver.new/3 takes after_step:, a (run_id, machine_state, effects -> any) callback fired after every step the driver takes on a caller's behalf - a durable subchart child's own steps and the parent's step on the answer path included, each under the id of the run that was stepped, with the whole effect list that step produced. It defaults to nil and may be overridden per call on create/3, send_event/4, done_invocation/5 and failed_invocation/5.

Fixed

  • StatifierPersistence.Testing.StorageConformance no longer registers a setup that writes: the input-log cases build their fixture run inside the case body, so a host's own setup - even one written below the use - is no longer preceded by a write. The moduledoc states the ordering contract a host binds against.

[0.10.0] 2026-09-06

Feature release: a durable subchart child failed from outside the interpreter now settles its parent's pending <invoke> instead of leaving it hanging forever. StatifierPersistence.Runs.fail/4 takes a driver: option and answers the parent itself, and StatifierPersistence.Driver.resolve_and_answer_parent/3 is the public form of that answer for a caller with no drive of the child to hang it off. Alongside it, StatifierPersistence.Ecto.Migrations.expected_version/0 names the newest migration version this package knows, for a host whose schema is hand-written DDL and which therefore has to check for itself that its tables are current.

Added

  • StatifierPersistence.Runs.fail/4 takes a driver: option: a durable subchart child failed from outside the interpreter now answers its parent's <invoke> with the failure instead of leaving it pending forever (ADR-0008's note on the outside-fail seam).
  • Adds StatifierPersistence.Driver.resolve_and_answer_parent/3, the public form of the automatic answer - resolve the parent's chart through chart_resolver:, then answer through answer_parent/3 - for a caller that has no drive of the child to hang it off.
  • StatifierPersistence.Ecto.Migrations.expected_version/0 returns the newest migration version this package knows, for a host whose schema is hand-written DDL rather than a delegated migration and which therefore has to check for itself that its tables are current. There is no assert_version!/1 to go with it: the package records no version marker in a repo's schema, so the comparison stays the host's - the function's docs say why.

Documentation

  • ADR-0010 takes a note answering whether a host needs the V05 input log table at all. An adapter that does not export the optional input-log callbacks never touches it - a host on one caps its migration at V04 in both directions rather than carrying an empty table - while a host storing through StatifierPersistence.Storage.Ecto needs it unconditionally, because that adapter declares input-log support without probing.

[0.9.0] 2026-09-06

Feature release: a durably stepped run can now keep a verbatim log of every input its interpreter saw, and a fan-out's settlement is visible in telemetry. The storage-adapter behaviour gains three optional input-log callbacks (supports_input_log?/1, append_input/3, list_inputs/2) and StatifierPersistence.Runs.inputs/2 reads the log back; Storage.Ecto implements them on Postgres and SQLite alike through migration V05, with an input_log_cap: bound and no log at all for an adapter that does not export the callbacks (ADR-0010, accepted). Two new events, [:statifier_persistence, :child, :recorded] and :settled, surface the per-child answers and the settlement decision that reach no door, and child.answered's outcome is now the invocation's rather than the door's, so a fan-out that failed no longer reports :done. And Storage.Ecto.list_runs_by_metadata/2 and list_run_states_by_metadata/2 refuse cleanly with {:error, :metadata_unsupported} off Postgres instead of raising from the driver.

Added

  • Adds an optional per-run input log to the storage-adapter behaviour (supports_input_log?/1, append_input/3, list_inputs/2): an adapter that exports them records every input a run's interpreter saw - the verbatim %Statifier.Event{}, the public door it entered by, and a dense zero-based ordinal - which is what an offline replay of a durably stepped run needs (ADR-0010).
  • Adds StatifierPersistence.Runs.inputs/2 and StatifierPersistence.Storage.input_log_supported?/1, append_input/4 and list_inputs/2 for reading and writing that log.
  • Adds migration V05, the input log table, on Postgres and SQLite alike; StatifierPersistence.Storage.Ecto implements all three callbacks and takes an input_log_cap: option that bounds a run's log and closes it with a marker entry rather than truncating it silently. The default is :infinity.
  • :blob_type now reaches the new input_blob column. An event's data is host payload, so turning the log on is a data-retention decision: an adapter that does not export supports_input_log?/1 keeps no log and behaves exactly as it did before.
  • Adds [:statifier_persistence, :child, :recorded], once per fan-out child answer written under the parent's settlement exclusion. Every index but the settling one records an answer that reaches no door, so this is the only surface those answers appear on (ADR-0009's sp-8wv amendment).
  • Adds [:statifier_persistence, :child, :settled], once per settlement decision, carrying the invocation's policy, the :answer / :not_yet decision, and the completed / failed / cancelled / unstarted tallies it was decided from.
  • [:statifier_persistence, :run, :step, :stop] now carries invoke_id and child_count, nil on an ordinary drive and set on the entry: :answer_parent step, so the step span that delivers a whole fan-out's assembled answer is recognisable as that one.

Changed

  • [:statifier_persistence, :child, :answered]'s outcome is now the invocation's for a fan-out, not the door's: :failed when any index failed. A fan-out always answers its parent through done_invocation/5
    • the failure shape is inside each entry - so the event previously said outcome: :done for a settlement that had failed. It also gains child_count and failed_count, both nil for a single-child subchart, which is not an invocation with a width. A consumer counting outcome across fan-outs will see failures it did not see before.
  • StatifierPersistence.Storage.Ecto.list_runs_by_metadata/2 and list_run_states_by_metadata/2 now return {:error, :metadata_unsupported} on a backend that is not Postgres, where they previously raised from the driver on jsonb containment SQL it cannot parse. Both consult supports_metadata?/1 before issuing anything, so a host calling the raw adapter callback gets the same clean refusal StatifierPersistence.Storage already gave through the facade. A behaviour change on two adapter callbacks: code rescuing the raise sees a tagged tuple instead. Nothing changes on Postgres, and the facade is untouched.

[0.8.0] 2026-09-06

Feature release: a chart can now report that its own run failed, and the Ecto adapter gains room to move on large and on non-Postgres hosts. A top-level <final> whose <donedata> sets run_status to "failed" persists the run as :failed so :first_error settlement fires (the ADR-0008 amendment, accepted). V04 of the DDL rebuilds V03's metadata GIN index with CREATE INDEX CONCURRENTLY - @current_version is now 4, and a host runs V04 as a migration of its own carrying @disable_ddl_transaction true and @disable_migration_lock true. A host that is not on Postgres has a documented opt-out: decline lock_run/3 with its own serialization: strategy and run the conformance suite with --exclude postgres. And Migrations.down/1 takes from:, the ceiling a capped migration needs to roll all the way back.

Added

  • A chart can now fail its own run: settling in a top-level <final> whose <donedata> carries statifier_persistence:run_status set to "failed" persists the run as :failed with the failure string "failed_final", so a :first_error fan-out cancels the failed child's siblings with no host-side translation.
  • docs/non-postgres-backends.md: the supported way to run the Ecto adapter on a backend that is not Postgres - decline lock_run/3 with your own serialization: strategy, what declining costs, and how to verify it.
  • StatifierPersistence.Ecto.Migrations.down/1 takes from:, the version it starts rolling back from (default: the newest this package knows), so a migration capped with up(version: 2) caps its rollback with down(from: 2).
  • V04 of the Ecto DDL rebuilds V03's metadata GIN index with CREATE INDEX CONCURRENTLY, so a host with a large runs table gets the index without the SHARE lock a plain build holds. Give it a migration of its own carrying @disable_ddl_transaction true and @disable_migration_lock true - Ecto reads those from your module, not from the helper - and call StatifierPersistence.Ecto.Migrations.up(for: MyApp.Persistence, from: 4). Called from an ordinary transactional migration it leaves V03's index in place instead of raising, warning when the runs table already holds rows. It is a no-op off Ecto.Adapters.Postgres, where V03 creates no index.

Changed

  • The conformance suite tags its four Postgres-only cases @tag :postgres - the two lock_run/3 cases and the two metadata-listing cases - so a host running Storage.Ecto on another Ecto backend runs it green with mix test --exclude postgres instead of forking the suite.

Fixed

  • mix ecto.rollback --all no longer fails for a host that caps one migration and takes a later version in another: without a ceiling every down/1 started at the newest version, so the capped migration rolled the later one's versions back a second time and failed on DDL that was already gone. Cap the rollback with from: as above.

[0.7.2] 2026-09-06

Patch release: a fan-out whose children settle at the same time assembles with every child's donedata present. A settlement used to read a sibling's status as terminal while that sibling's answer was still in flight, and assembled a completed child with a nil donedata; a settlement now records its own answer under the parent's exclusion and waits for every child's recorded answer, not only for every child's terminal status.

Fixed

  • A fan-out invocation whose children settle concurrently no longer answers with a nil donedata for a child that completed: a settlement waits for every child's answer to be recorded, not only for every child's status to be terminal, and records its own answer under the parent's exclusion.

[0.7.1] 2026-09-05

Patch release: hosts that are not on Postgres can apply the package DDL. V03 creates its metadata GIN index only on Postgres, and the Ecto adapter now answers supports_metadata?/1 by adapter, so a store that could not settle a durable subchart or a fan-out is refused at open rather than crashing partway through.

Fixed

  • V03 of the Ecto migration helper is adapter-aware: the metadata GIN jsonb_path_ops index is created (and dropped) only when the migration's repo runs on Ecto.Adapters.Postgres. On any other adapter it is skipped and the migration runs to completion, so a host on another backend can apply the package DDL at all - in 0.7.0 the index raised, the whole migration rolled back, and the outcome_blob column went with it. The column itself is still created on every adapter, and StatifierPersistence.Storage.Ecto.supports_run_outcome?/1 is still true everywhere.
  • StatifierPersistence.Storage.Ecto.supports_metadata?/1 now answers false off Postgres, because both metadata queries the adapter issues are jsonb containment SQL. StatifierPersistence.Storage's child_listing_supported?/1 and run_states_supported?/1 consult it, so a durable subchart or a fan-out over such a store is refused at open (:child_listing_unsupported) rather than started and left with children nothing could settle. Behavior on Postgres is unchanged.

[0.7.0] 2026-09-05

Feature release: a scheduler can start a Tier A fan-out through a public door, and the N children settle once as a dense, index-ordered list instead of each answering the parent. Hosts on the Ecto adapter run a new V03 migration.

Added

  • StatifierPersistence.Driver.start_child_at/6: the public start-with-index door a scheduler drives a Tier A fan-out through. Starts child i of N for a parent's <invoke>, records the count and the aggregation policy (:all or :first_error) on the child's linkage, and is idempotent on the derived child run id, so a re-delivered start adopts rather than duplicating. Refuses at open on a store that could not settle the invocation afterwards.
  • StatifierPersistence.Run.Linkage.new/6 and fan_out?/1: a child's linkage can now carry its invocation's child_count and aggregation policy (:all or :first_error), which is what marks it as one of a fan-out's N rather than an ordinary durable subchart.

Changed

  • The storage-adapter run_record gains a nullable outcome_blob: a run's own answer, written once when it reaches a terminal status through StatifierPersistence.Storage.update_run_status/4's new outcome_blob: option. update_run/2 carries a stored payload forward when the record it is given carries none, so an ordinary step never erases one. Adapters gain two optional callbacks alongside it - supports_run_outcome?/1 and list_run_states_by_metadata/2, the indexed status projection - and an adapter that exports neither is conformant unchanged.
  • The Ecto adapter's V03 migration adds the outcome_blob column and a GIN jsonb_path_ops index on metadata. A host already on V02 picks it up with StatifierPersistence.Ecto.Migrations.up(for: MyApp, from: 3). Run it before deploying 0.7.0, and read the README's "Upgrading to V03 before deploying 0.7.0" first: the index build is a plain CREATE INDEX that blocks writes to the runs table for the length of the build.
  • StatifierPersistence.Driver takes a child_canceller: option: how a :first_error settlement asks the scheduler to cancel the start jobs of a fan-out's not-yet-started children, which have no run record for the cascade to reach.
  • A fan-out child's completion now settles instead of answering its parent's door: its answer is stored on its own run record, and only the settlement that finds all N indices terminal assembles the dense, index-ordered list and answers the invocation once. StatifierPersistence.Driver.answer_parent/3 routes a fan-out child the same way and returns :ok for it. A child with no child_count on its linkage - every child created before this release - is unaffected.

[0.6.0] 2026-09-02

Feature release: a durably-stepped run is observable through statifier's own session telemetry, so the OpenTelemetry bridge produces the same spans and effect events for a durable run as for a session-hosted one.

Added

  • Durably-stepped runs now emit statifier's own [:statifier, :session, ...] telemetry with driver: :persistence, so opentelemetry_statifier produces the same macrostep spans and effect events for a durable run as for a session-hosted one, with no bridge change.

[0.5.0] 2026-09-01

Feature release: the durable step is observable, and a :dispatch fun can see the whole <invoke> it is being handed.

Added

  • StatifierPersistence.Driver.dispatch_context/0 carries :invoke, the whole Statifier.Effect.Invoke being dispatched, so a :dispatch fun can read the element's src - the document id a subchart handler resolves its child chart by - along with content, autoforward, and the step counters.
  • StatifierPersistence.Telemetry emits the fourteen [:statifier_persistence, ...] events ADR-0009 specifies - the durable step as a :start/:stop pair, the per-run lock wait, every storage-adapter call, identity refusals, the run lifecycle, executor failures, and the durable-subchart seam - and events/0 returns every name for a bridge to attach to.
  • Adds a direct :telemetry dependency (already present transitively through statifier, so no lock file grows).

[0.4.0] 2026-09-01

Feature release: durable subcharts (ADR-0008) - an <invoke> may start a child chart as an ordinary durable run, the parent rests holding no process while the child runs, and leaving the invoking state cancels the child subtree.

Breaking for storage adapters: run_status/0 gains a fourth terminal value, :cancelled. An adapter that encodes run statuses by an exhaustive match must add a clause for it before upgrading, or cancelled runs will fail to persist. The two adapters in this package already handle it.

Added

Changed

  • StatifierPersistence.Storage.Adapter.run_status/0 gains a fourth terminal value, :cancelled. An adapter that encodes statuses by an exhaustive match must add a clause for it, or cancelled runs will fail to persist.
  • StatifierPersistence.Run gains donedata, set only on the step that completes a run and nil everywhere else.

[0.3.0] 2026-09-01

Feature release: an asynchronous invocation seam on the durable driver - a dispatch may answer :pending and the run rests holding no process, with public doors that answer the invocation later from any process or node.

Added

Changed

  • The context handed to a :dispatch fun carries invoke_id, the invocation id an asynchronous host keys its work by and hands back to the re-entry doors.

[0.2.0] 2026-08-31

Feature release: a durable run-to-quiescence driver, opaque run metadata, and a custom blob type for encryption at rest.

Added

  • StatifierPersistence.Driver drives a durable run to quiescence over StatifierPersistence.Runs: it performs each <invoke> through a host-supplied dispatch fun inside the step that emitted it, then steps every answer back in until the chart rests. Hosts that hand-rolled this loop can delete it.
  • StatifierPersistence.Driver builds an invocation's answer events - done.invoke.<id> and error.communication.invoke.<id>, origin and origintype included - field for field from Statifier.Session's own done_invocation/3 and failed_invocation/3, so a chart sees the same event in a session and out of storage. A conformance test answers one document both ways and compares what each chart saw.
  • StatifierPersistence.Runs.create/4 and StatifierPersistence.Storage.insert_run/5 accept an optional metadata: map of string keys, stored opaquely beside the run record and returned by fetch_run/2 unchanged (ADR-0006). Host identities only, never personal data: blob encryption does not reach this column.
  • StatifierPersistence.Storage.Adapter gains the optional supports_metadata?/1 callback and a metadata field on run_record. An adapter that does not export it refuses a non-empty map at create with {:error, :metadata_unsupported}; an empty or absent map is never refused, so every existing adapter stays conformant unchanged.
  • StatifierPersistence.Storage.metadata_supported?/1 and check_metadata/2 report whether a store's adapter can hold metadata, without writing anything.
  • StatifierPersistence.Storage.Ecto.list_runs_by_metadata/2 lists the runs whose metadata contains every given key/value pair.
  • Migration V02 adds a nullable jsonb metadata column to the runs table, and StatifierPersistence.Ecto.Migrations.up/1 accepts from: so a host already on V01 applies later versions in its own second migration.
  • StatifierPersistence.Testing.StorageConformance gains metadata cases: a conformant adapter either round-trips the map or refuses it at open, and never silently drops it.
  • use StatifierPersistence.Ecto accepts a :blob_type option to put a custom Ecto type on the three blob columns (identity_blob, chart_blob, position_blob), enabling encryption at rest with no wrapping adapter.

Changed

  • Requires statifier ~> 2.2 and >= 2.2.1 rather than ~> 2.0: 2.2.1 is the first release carrying the queue-discard-on-exit fix the completion conformance cases need. (An interim git-ref pin served between 2.2.0 and that release.)

Fixed

  • A run whose top-level <final> is reached while sibling done.state.* events are still queued now persists as completed, instead of raising "loop bug: non-quiescent MachineState reached the persist tail". The same holds for a top-level <final> whose <donedata> expression fails.
  • StatifierPersistence.Runs.create/4 passes only its metadata: pair to StatifierPersistence.Storage.check_metadata/2, whose contract is the narrower [Storage.run_write_opt()]. Handing the whole option list over made dialyzer derive a success typing for create/4 that accepted no executor: at all, so an embedder had to suppress "will never return" on every correct call; that suppression can now be deleted.

[0.1.3] 2026-08-27

Docs release: README and guide refresh onto the family's canonical example domains. No library code changes.

Changed

  • The README now walks a full worked run in the card-processing domain - load, step, execute effects, persist - and continues it across a restart, with a new module map; the examples are executed by a test so they cannot drift from the real API.
  • Example domains follow the family rule: card processing and the signup wizard with A/B testing only.
  • Agent tooling: gate attestation points at mix quality.verify (shipped by ex_quality 0.14) instead of a retired local task.

[0.1.2] 2026-08-24

Docs release: the hexdocs/README overhaul from PR #20. No library code changes.

Changed

  • Hexdocs no longer publishes the ADRs: the ADR extras and their groups_for_extras entry are removed, so the published docs are the README, this changelog, and the restart-demo guide.
  • ex_doc is pinned to ~> 0.40, and CHANGELOG.md is listed in skip_undefined_reference_warnings_on; mix docs now completes with zero warnings.
  • The README gains the standard badge row (CI, hex.pm version/downloads, hexdocs, license) and a documentation index line linking the published restart-demo guide.

[0.1.1] 2026-08-24

Patch release: the key-generator compile-race fix from PR #18.

Fixed

  • Custom key-generator validation in use StatifierPersistence.Ecto no longer fails spuriously when the generator module is still being compiled by the host's parallel compiler; validation now waits for in-flight compilation (Code.ensure_compiled/1) instead of checking Code.ensure_loaded?/1.

[0.1.0] 2026-08-22

First release: the persistence-first execution loop for the statifier statechart engine - load a persisted position, step it, execute the effects, persist - packaged as a storage-adapter behaviour with an identity guard, an in-memory reference adapter, a run lifecycle, and an Ecto/Postgres layer, all covered by one conformance suite downstream adapters inherit.

Added

  • StatifierPersistence.Storage.Adapter, the storage contract, including run records: insert_run/2, fetch_run/2, and update_run/2 callbacks with run_record/run_status types and the :run_exists / :run_not_found error arms; StatifierPersistence.Storage.InMemory is the reference implementation.
  • Guarded run access on the facade: StatifierPersistence.Storage.insert_run/5, update_run/5, fetch_run/2, and load_run_position/3 (identity-guarded, with the :run_position_missing arm for a run persisted without a position).
  • Run-record conformance tests in StatifierPersistence.Testing.StorageConformance, so downstream adapters inherit the same contract checks.
  • The run lifecycle as a library: StatifierPersistence.Runs.create/4 and step/5 drive the load -> re-stamp -> step -> execute -> persist loop over durable run records, handing effects to a host-supplied StatifierPersistence.Executor (behaviour or arity-2 fun) and returning the host-facing StatifierPersistence.Run struct; events to a terminal run come back as {:discarded, run}.
  • Failure semantics on the loop: executor failures on actionable effects re-enter the chart as error.communication events (single wave per step, observational failures discarded); effect execution is at-least-once, with a failed persist re-driving the same event and re-emitting the same effects under identical deterministic keys; budget exhaustion persists a :failed run (position untouched) and returns {:error, {:budget_exhausted, payload}}.
  • StatifierPersistence.Runs.fail/4, the host-driven abandonment: marks an active run :failed with a reason, leaves the stored position untouched, and discards on a terminal run - backed by the status-only writer StatifierPersistence.Storage.update_run_status/4.
  • Pluggable per-run serialization: the StatifierPersistence.Serialization behaviour (with_run/3), selected per lifecycle call with serialization: {module, config} on Runs.create/4, step/5, and fail/4. The default strategy, StatifierPersistence.Serialization.AdapterLock, delegates to the optional adapter callback StatifierPersistence.Storage.Adapter.lock_run/3 (implemented by InMemory, conformance-tested when exported) and refuses with {:error, {:serialization, :not_supported}} when the adapter does not export it.
  • use StatifierPersistence.Ecto: compile-time configuration on the host's module (repo:, key:, table_prefix:, tables:, prefix:) that defines Chart, Position, and Run schema modules and exposes the resolved config via __statifier_persistence__/1. Requires the optional ecto_sql dependency.
  • StatifierPersistence.Ecto.KeyGenerator: the behaviour a surrogate-key scheme implements, with :uxid (default), :uuid (UUIDv7), :bigserial, and {module, opts} resolved through resolve/1.
  • StatifierPersistence.Ecto.Migrations: the versioned migrations helper (up/1, down/1, taking for: HostModule or the same literal options use takes) that creates the charts/positions/runs tables from the same resolved config the schemas use.
  • StatifierPersistence.Storage.Ecto: the Postgres storage adapter over the schemas a host generates with use StatifierPersistence.Ecto (Storage.new(Storage.Ecto, persistence: MyApp.Persistence)). Passes the same conformance suite as the in-memory reference adapter; engine identities stored verbatim; :run_exists enforced atomically by the unique index.
  • Storage.Ecto.isolate/1: with sandbox: true, wraps each test in its own Ecto.Adapters.SQL.Sandbox checkout - the hook host test suites (and this package's conformance suite) isolate through.
  • Storage.Ecto.lock_run/3: per-run mutual exclusion as a transaction-scoped pg_advisory_xact_lock plus a SELECT ... FOR UPDATE row lock (ADR-0004 as amended), consumed by Serialization.AdapterLock.
  • uxid is a required dependency (the default key scheme works out of the box); ecto_sql is optional and the package compiles without it.