How exactly i can add an error into nested/embedded changeset? Don’t think add_error can do this.
Context: regular changeset validation already happened and i’m doing some external check
e.g.
...
defmodule Thing do
schema "things" do
embeds_one :config, ThingConfig, on_replace: :update
end
end
...
defmodule ThingConfig do
@primary_key false
embedded_schema do
field :param, :string
end
end
# ??
ch1 = Ecto.Changeset.add_error(ch.changes.config, :param, "error")
# ??????
Ecto.Changeset.put_embed(ch, :config, ch1)
on insert it works, on update - error:
Since you have set :on_replace to :update, you are only allowed
to update the existing entry by giving updated fields as a map or
keyword list or set it to nil.
1 Like
update_in(ch.changes.config, fn changeset ->
Ecto.Changeset.add_error(changeset, :param, "error")
end)
Just be aware that this won’t make the parent become valid?: false.
3 Likes
Well, this use-case seems to be missing - it’s possible to make it work but requires some manual labor, e.g. it’s not guaranteed ch.changes.config will be actually set and various get_field, apply_changes etc will skip current validation info. valid?: false, as mentioned above. No issues though. Works for me.
And what would be the proper way to invalidate the parent changeset on the way?
Afaik it’s only manipulating valid? manually on all parent changesets to the one manipulated. I don’t think there’s more to it.
I see, TNX. BTW, that’s what I am doing right now but was hoping that there might be something I am not aware of that would do this for me.
My case is that I embed_many and all of them in their own context are valid, but the parent needs to check whether all embedded ones are unique (in some way) and mark those, which are not. So I traverse the embedded ones and add_error/4 to non-unique ones. It is used in conjunction with on_replace: :delete so not so much need for taking care of “unsafe-ness” of this uniqueness check, I reckon.
But maybe there’s a better approach to this problem in general?
UPDATE:
new_embedded_changesets = Enum.map(changeset.changes.my_embed_many, fn embedded_changeset ->
if !Enum.empty?(embedded_changeset.changes) && Enum.member?(duplicates, embedded_changeset.changes[field]), do: add_error(embedded_changeset, field, "has to be unique"), else: embedded_changeset
end)
# This (update_change/3) seems to do the trick so far
update_change(changeset, :tax_rates, fn _original_embedded_changesets -> new_embedded_changesets end)
where duplicates are found earlier, of course
