Sample

Verify that start_link eagerly checks worker module existence and validates pool_size type

sha256:f3bdf79601e6d0cb079ae5187e83d3ea06e4b2ed2c35f223db15ccb9dd6be4d8

Case

Goal

Verify that start_link eagerly checks worker module existence and validates pool_size type HOW

Packages

nimble_pool 1.1.0

Environment

elixir

Created

2026-08-16T15:08:03Z

Commonly assumed

A model expects that starting a lazy pool with lazy: true defers worker module validation until checkout, allowing start_link to return {:ok, pid} even when given an unresolvable worker module or an atom :infinity for pool_size.

The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.

Contract

• NimblePool.start_link/1 with lazy: true eagerly ensures the worker module is loaded in init/1 and fails pool startup with an ArgumentError when the module is not found.
• NimblePool.start_link/1 strictly validates that :pool_size is a positive integer, raising an ArgumentError when passed atom options like :infinity that passed comparison in earlier versions.
• NimblePool.start_link/1 raises an ArgumentError when the required :worker option is omitted.

Files

• NOTES.md
• csx.json
• mix.exs
• mix.lock
• test/contract_test.exs
• test/test_helper.exs

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• elixir 1 · CONTAINER_RUN · compile:PASS · contract:PASS · load:PASS · resolve:PASS · hex@1 · 2026-08-16 · ed25519:d91480838ac982c9