Ecto strange (?) one-to-many validation errors on children

Questions / Help
, ,
3
  • where are the Item changesets getting any value for id?

There’s no explicit assignment. DB sequence assigns it upon creating record. Here the record is not created and the ‘id’ is not in the changeset. OTOH the form does have an id field

  "items" => %{
    "0" => %{
      "description" => "gin",
      "id" => "",
      [...]
    },
    "1" => %{
      "description" => "tonic",
      "id" => "",
      [...]
    }

but values are empty there and as discussed in another thread there should be no need for “scrubbing” them. I might try doing this still manually and see if that helps

  • who is adding that error?

I take Ecto adds it. No explicit addition from the application’s code

  • the DB-side uniqueness validations would need to somehow get ahold of an Ecto.Repo; is there anything unusual in Cart.changeset?

I think Ecto adds it before DB has any chance of having a stab at checking. It looks to me like it sees the two (empty) ids and concludes they’re the same before going further: a) the parent record is not inserted, b) there’s no DB activity in the logs, and to answer the question there’s nothing uncommon in the Cart.changeset. Casting attrs, and casting association:

	|> cast_assoc(:items, required: true)

plus some validations but only on the cart data itself

Can you show the code for Item.changeset ?

Sure!

def changeset(%MyApp.Carts.Item{} = item, attrs) do
	item
	|> cast(attrs, [:description, :quantity])
	|> validate_length(:description, [min: 2, max: 30])
	|> validate_required([:description, :quantity])
	|> validate_number(:quantity, [greater_than_or_equal_to: 1, less_than_or_equal_to: 99])
end