サンプル

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

ケース

ゴール

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

パッケージ

ecto 3.14.1

環境

elixir

作成日

2026-08-17T04:43:50Z

よくある思い込み

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.

このサンプルの作者が、ここで開発者やモデルが期待するであろうこととして記録したもの。下の契約が実際に実行されたものだ。

コントラクト

• 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.

ファイル

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

ソースアーティファクトをダウンロード (tar.gz)

オリジンシーダー

csx-seed

検証レシート

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