Exemplo

Manage unloaded association state with Ecto.Association.NotLoaded, handle put_assoc exceptions on uninitialized associations, and track retained parent state across build_assoc and apply_changes

sha256:273ee8a646360bca1986c52809ca47909c22e94a5026a62c46b23c56c2eefb3d

Caso

Objetivo

Manage unloaded association state with Ecto.Association.NotLoaded, handle put_assoc exceptions on uninitialized associations, and track retained parent state across build_assoc and apply_changes HOW

Pacotes

ecto 3.14.1

Ambiente

elixir

Criado

2026-08-17T04:43:50Z

O que costuma-se supor

A competent developer expects put_assoc/4 to associate child records directly onto any struct or changeset, assuming schema association fields default to empty collections or nil when newly constructed.

O autor da amostra registrou aqui o que um desenvolvedor ou um modelo esperaria. O contrato abaixo é o que de fato rodou.

Contrato

• Calling put_assoc/4 on a loaded struct with unloaded associations raises RuntimeError because uninitialized associations hold an %Ecto.Association.NotLoaded{} struct rather than nil or [], and Ecto.assoc_loaded?/1 returns false.
• Explicitly initializing the association field on the struct to [] (for has_many) or nil (for has_one/belongs_to) marks the association as loaded with Ecto.assoc_loaded?/1 returning true, allowing put_assoc/4 to succeed on loaded structs.
• Calling Ecto.build_assoc/3 constructs the child schema struct with the parent's primary key mapped to foreign keys, but leaves the parent struct's association field retained as %Ecto.Association.NotLoaded{}.
• Executing apply_changes/1 updates fields and embeds into structs while preserving %Ecto.Association.NotLoaded{} on untouched associations, and leaves prepare_changes/2 lifecycle callbacks unexecuted.
• Passing parameters with unpermitted fields to cast/4 populates changeset.changes with permitted fields only, but retains all unpermitted and sensitive keys in changeset.params.

Arquivos

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

Baixar o artefato de código-fonte (tar.gz)

Seeder de origem

csx-seed

Recibos de verificação

• elixir 1 · linux alpine/x64 · docker · CONTAINER_RUN · compile:PASS · contract:PASS · load:PASS · resolve:PASS · hex@1 · 2026-08-17 · ed25519:d91480838ac982c9