2.0.0 (2026-05-09)

⚠ BREAKING CHANGES

• kernel: change event store behavior to return result tuples
• kernel: rename domain to aggregate_type (everywhere)
• kernel: use aggregate_id instead of stream_id
• kernel: rename command key() to target() for clarity
• kernel: refine command, event and snapshot keys
• kernel: route all commands through a singleton aggregate manager
• kernel: remove manager behaviour (used for routing)
• kernel: remove lifecycle management from kernel layer
• kernel: turn the kernel into a plain OTP app

Features

• contract: add contain/2 to the range ADT (0f3eb9e)
• contract: add difference/2 to the range ADT (cadf54a)
• contract: add equal/2 to the range ADT (4a85896)
• contract: add intersection/2 to the range ADT (31fb6c8)
• contract: add lt/2 to the range ADT (439d82d)
• contract: add overlap/2 to the range ADT (5542f1f)
• contract: add projection checkpoint store behavior (61c3bc7)
• core: refine store startup and validation (5ed9e55)
• example: extract interactive bank account example into standalone script (5ea9e33)
• kernel: add projection event log folding (7bb5ce7)
• kernel: add projection runtime (9ee6ddd)
• kernel: handle aggregate process failures in command dispatch (f9c8691)
• kernel: introduce registry mapping aggregate_type to aggregate_module (0e2acc9)
• kernel: make snapshot interval configurable (d4b0f57)
• projection: add managed projection runners (1ccc6ae)
• store_ets: add global event positions (b397992)
• store_file: add File store backend (e16058b)
• store_file: add global event index (19f5d73)
• store_mnesia: add global event positions (0c09f08)
• xp: improve xp (demo) application (32f777d)
• xp: wire projection runtime into demo app (8c829cc)

Bug Fixes

• contract: correct behavior of advance/2 to return empty range when beyond upper bound (4f7f60a)
• contract: correct error tuple for invalid range creation (dff2608)
• file: handle file:write_file error return type (1c6b31e)
• kernel: add (missing) event_type/1 callback to aggregate behavior (97ec156)
• kernel: add warning log for missing registry entry in init/1 (c67b810)
• kernel: align manager dispatch specs with actual return types (95774e9)
• kernel: make checkpoint ets startup race-safe (1c5e5db)
• kernel: preserve event order in aggregate batches (59046e4)
• xp: enforce positive withdraw amounts (813f7da)

Documentation

• kernel: document projection runner failure mode (7e768e4)
• kernel: tighten aggregate process documentation (ff3cea9)
• README: add codecov badge (c1aa4e3)
• README: add pull-based projection runtime and checkpointing details (2dde721)
• README: clarify command payload and aggregate type resolution (19af86b)
• README: describe file store backend (+ cosmetics) (dd9174a)
• README: describe lint workflow (dialyzer, fmt) (9663a18)
• README: document global event folding (fa2f543)
• README: document kernel refactor and supervision tree (fdd21b4)
• README: document managed projections (8cfdf16)
• README: document projection app runtime (6a4de80)
• README: include capabilities for each store (29bfe3c)
• README: refresh feature overview (1eee3a9)
• README: specify event store backend roadmap (e91c279)

Styles

• contract: polish style (14990a8)
• fix line length lint (8ee4e12)
• kernel: make linter happy again (7f509bb)
• kernel: simplify metadata and tags handling (0214388)

Refactors

• apply es_ prefix to all modules (simplify naming) (8ceee1e)
• contract: change fold callback to use interval as first-class parameter (6a020f2)
• contract: rename interval ADT into range (c6c3056)
• core: split store behaviours (a6022c2)
• extract event sourcing contract into dedicated app (33241ee)
• kernel: change event store behavior to return result tuples (8186b17)
• kernel: configure store via OTP application environment (6fb6c45)
• kernel: extract rehydration logic from aggregate init (60c7c70)
• kernel: migrate es_kernel_aggregate_sup to modern dynamic supervisor (f2001cf)
• kernel: refine command, event and snapshot keys (8ad27c2)
• kernel: remove lifecycle management from kernel layer (07ddecb)
• kernel: remove manager behaviour (used for routing) (acb0e75)
• kernel: remove wrapper functions from es_kernel_store (d835daf)
• kernel: rename command key() to target() for clarity (58d60e9)
• kernel: rename dispatch to execute in es_kernel_aggregate (cb49631)
• kernel: rename domain to aggregate_type (everywhere) (4188fc1)
• kernel: restructure stream_id as {domain, aggregate_id} tuple (b475ab7)
• kernel: route all commands through a singleton aggregate manager (ed6c697)
• kernel: turn the kernel into a plain OTP app (b7af467)
• kernel: use aggregate_id instead of stream_id (eade7e5)
• merge es_contract into es_kernel application (f23018a)
• move contract types to dedicated modules (6c9bd74)
• projection: move projection runtime to dedicated app (93a5f07)
• range: normalize/relax range creation logic (8cac1d9)
• remove configurable sequence_zero and sequence_next functions (055087e)
• rename es_core to es_kernel (d7fd4c1)
• rename event store and snapshot store callbacks (74a5dc4)
• reorder fold/4 callback parameters (39d927e)
• split store backends into dedicated apps (fa9dd51)
• store_ets: make store_es a standalone OTP application (73f716d)
• store_ets: parametrize table name with configurable defaults (d66b918)
• store_mnesia: make store_es a standalone OTP application (d37902e)
• store_mnesia: parametrize table name with configurable defaults (de2300e)
• store: clarify meaning of store context (844e054)
• store: split event and snapshot stores (bcb6199)

Performance Improvements

• kernel: optimize retrieve_events to build event lists in O(n) (889be9e)

Tests

• contract: add comprehensive unit tests for event_sourcing_interval module (012d846)
• contract: cover contain/2 for the range ADT (f9839c1)
• contract: cover difference/2 for the range ADT (90a7533)
• contract: cover equal/2 for the range ADT (b6072e1)
• contract: cover intersection/2 for the range ADT (a7d047b)
• contract: cover lt/2 for the range ADT (b73e816)
• contract: cover overlap/2 for the range ADT (2fd9119)
• contract: make range tests black-box (f994fa5)
• kernel: add aggregate_survives_dead_worker test case (cb450e0)
• kernel: cover file store backend (0236ec9)
• kernel: cover global event folding (1e65094)
• kernel: cover projection runtime (5d779e3)
• projection: cover projection management (79830cd)
• projection: ensure polling runner cleanup (f5e6a33)
• remove domain from aggregateId (not necessary) (ced40f8)
• xp: put bank_account_aggregate under testing (21f5df0)

Build System

• agents: bring erlang_otp_developer to life (43d6fc1)
• agents: remove unnecessary tools field (61731ec)
• deps: bump actions/cache from 4 to 5 (2db2fc8)
• deps: bump actions/checkout from 5 to 6 (beed6fc)
• deps: bump codecov/codecov-action from 5 to 6 (4a3c7a4)
• deps: bump crazy-max/ghaction-import-gpg from 6 to 7 (8522c7c)
• project: configure covertool coverdata properly (809ce64)
• rebar: add projection app to umbrella (25fce84)
• release: add escript to generate release BOM (dcaf2f4)
• release: categorize non-feature commits in changelog (ec7d421)

Continuous Integration

• codecov: ignore demo app coverage (4a597e2)
• workflow: addcoverage reporting job and upload to Codecov (22c0631)
• workflow: ensure injected demo snippet is up to date (884609c)
• workflow: fix example script path (deea666)

Chores

• project: add data directory to git ignore list (9cdf6a3)