Work directly from a clean checkout and keep changes focused on one behavior. New behavior starts with a test that fails for the intended reason.

The test suite requires a dedicated PostgreSQL 18 database on 127.0.0.1:18841. The suite fails closed unless DATABASE_URL points at exactly that database and port; it rejects any other name or port.

Before creating the container, verify that neither a container named ash-onetime-postgres nor a listener on port 18841 already exists. Reuse the existing container across sessions; do not start a second database on another port.

docker run --name ash-onetime-postgres \
  -e POSTGRES_USER=postgres \
  -e POSTGRES_PASSWORD=postgres \
  -e POSTGRES_DB=ash_onetime_test \
  -p 127.0.0.1:18841:5432 \
  -d postgres:18

export DATABASE_URL=ecto://postgres:postgres@127.0.0.1:18841/ash_onetime_test
mix deps.get
mix test

Before reporting a change complete, run:

mix format --check-formatted
mix compile --warnings-as-errors
mix test
mix credo --strict
mix dialyzer
mix deps.audit
mix hex.audit
mix spark.cheat_sheets --check --extensions AshOnetime.Resource
mix docs --warnings-as-errors
DATABASE_URL=ecto://postgres:postgres@127.0.0.1:18841/ash_onetime_test \
  MIX_ENV=test mix run scripts/check_mutations.exs -- all
mix hex.build
mix run scripts/check_package.exs

Inspect the Hex archive by exact file allowlist and compile/test an unpacked archive consumer; building an archive alone is not package proof. Remove the generated tar after verification.

Run the gate battery on the runtime pinned in .tool-versions (Elixir 1.20.2, Erlang/OTP 29), which is the supported and released runtime.

Every mutation row must name one exact source edit, one owned test and assertion, demonstrate RED, restore the exact source bytes, and demonstrate GREEN. New public modules or dependencies must update the exact architecture census. Public documentation changes must regenerate the Spark reference and pass warnings as errors.

Never commit secrets, provider-specific signature implementations, reference-project dependencies, or project-owned version suffixes in durable identifiers.

Dependency compatibility

The published mix.exs bounds (ash_postgres ~> 2.11, spark ~> 2.7, and the Ash floor >= 3.31.1) allow forward drift within their major lines. They are NOT the primary guard against a transitive semantic shift — a future ash_postgres 2.x or spark 2.x minor that changes transaction-visibility semantics the fail-closed logic depends on would still satisfy the bound. The real guard is the CI compatibility matrix in .github/workflows/ci.yml:

  • the declared Ash floor (3.31.1, CVE-justified per ADR-0004);
  • a floating latest cell that resolves the newest published Ash 3.x on every run via deps.unlock ash / deps.update ash and re-runs the full gate battery against it.

Forward drift that breaks the fail-closed surface surfaces as a red latest cell, not as a bound violation. When updating a dependency bound, ensure the matrix still covers the new range; tightening a bound without matrix coverage is a regression in the guard. A breaking major bump of ash_postgres or spark (3.x for either) is a matrix-extension event first — add the cell, confirm green, then update the bound.

Never commit secrets, provider-specific signature implementations, reference-project dependencies, or project-owned version suffixes in durable identifiers.