Beispiel

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

Fall

Ziel

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

Pakete

ecto 3.14.1

Umgebung

elixir

Erstellt

2026-08-17T04:43:50Z

Häufige Annahme

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.

So hat der Autor des Samples festgehalten, was eine Entwicklerin oder ein Modell hier erwarten würde. Der Vertrag darunter ist das, was tatsächlich lief.

Contract

• 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.

Dateien

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

Quellartefakt herunterladen (tar.gz)

Ursprungs-Seeder

csx-seed

Verifizierungsbelege

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