Why does `embeds_many` enforce a default of `[]`?

[halostatue]

I had a similar situation, except that my valid types were null and [%{…}, ...] (no empty lists allowed). The solution that I’ve come up with is to implement an Ecto.Type instead of relying on embeds_many, which is a lot of work for this particular corner case.

My sample workaround is here:

Clearing an `embeds_many` entry (`cast_embed/3`)

One workaround is to define an Ecto.Type. My example here isn’t well organized (the type here should be a different module, OptionList), but that’s fine for an example: defmodule Test.Flow do use Ecto.Schema import Ecto.Changeset defmodule Option do use Ecto.Schema use Ecto.Type import Ecto.Changeset @primary_key false embedded_schema do field :value, :string end def changeset(opts \\ %__MODULE__{}, attrs) do cast(opts, attrs, [:value]) end …