Getting some weird error after generating codes using "mix.gen.live" commands more than once in an app

Phoenix Forum Questions / Help
1

When generating codes using “mix.gen.live” more than once in the same app, there always is an error MAYBE generated by more than one “form_component.ex” modules which are using the same “core_component.ex”.

I am still confused whether it’s a bug in LiveView or that of my app.

** (KeyError) key :name not found in: %{__changed__: nil, __given__: %{__changed__: nil, field: %Phoenix.HTML.FormField{id: "demographic_gender", name: "demographic[gender]", errors: [], field: :gender, form: 

... omitted 

lib/market_web/components/core_components.ex:353: anonymous fn/2 in MarketWeb.CoreComponents."input (overridable 1)"/1 

--- omitted

Yesterday, I have spent eons of time to fix it, but in vain.

Thank you for reading, any comment shall be appreciated.

2

The CoreComponents are meant to be reused.
Most of the time I see an error like this is when I use a <.input ..> that has no name attribute.

3

Thank you for hint.
The error is clearly from the <.input …> field of FormComponent.ex, as commenting out those two <.input…> fields yields no error, but screen without input fields.

def render(assigns) do
    ~H"""
    <div>
      <.header>
        <%= @title %>
        <:subtitle>Use this form to manage demographic records in your database.</:subtitle>
      </.header>

      <.simple_form
        for={@form}
        id="demographic-form"
        phx-target={@myself}
        phx-change="validate"
        phx-submit="save"
      >
        <.input field={@form[:gender]} type="text" label="Gender" />
        <.input field={@form[:year_of_birth]} type="number" label="Year of birth" />
        <:actions>
          <.button phx-disable-with="Saving...">Save Demographic</.button>
        </:actions>
      </.simple_form>
    </div>
    """
  end

But, I can’t fix it.

4

Try with adding a :let={f} to the form and rewriting as field={f[:gender]}

5

Tried, but not working.

The render() function above was auto generated by “mix.gen.live”, so is expected to work as it is.

It seems a bug in the current LiveView 0.8.x.

Thank you ermanverschooten for help. :slightly_smiling_face:

6

Just wondering, do you have this in your core_components.ex?

  def input(%{field: %Phoenix.HTML.FormField{} = field} = assigns) do
    assigns
    |> assign(field: nil, id: assigns.id || field.id)
    |> assign(:errors, Enum.map(field.errors, &translate_error(&1)))
    |> assign_new(:name, fn -> if assigns.multiple, do: field.name <> "[]", else: field.name end)
    |> assign_new(:value, fn -> field.value end)
    |> input()
  end
7

Yes, there is, but slightly different version. I’m using {:phoenix_live_view, “~> 0.18.3”},

def input(%{field: {f, field}} = assigns) do
    assigns
    |> assign(field: nil)
    |> assign_new(:name, fn ->
      name = Phoenix.HTML.Form.input_name(f, field)
      if assigns.multiple, do: name <> "[]", else: name
    end)
    |> assign_new(:id, fn -> Phoenix.HTML.Form.input_id(f, field) end)
    |> assign_new(:value, fn -> Phoenix.HTML.Form.input_value(f, field) end)
    |> assign_new(:errors, fn -> translate_errors(f.errors || [], field) end)
    |> input()
  end

I have added your version too, but still not works. The error seems related to postgresql because sometimes the error message below shown when routing to a form_component.

[error] #PID<0.1420.0> running Phoenix.Endpoint.SyncCodeReloadPlug (connection #PID<0.1339.0>, stream id 3) terminated
Server: localhost:4000 (http)
Request: GET /demographics
** (exit) an exception was raised:
    ** (Protocol.UndefinedError) protocol Phoenix.Param not implemented for {"demographics-1", %Market.Survey.Demographic{__meta__: #Ecto.Schema.Metadata<:loaded, "demographics">, id: 1, gender: "prefer not to say", year_of_birth: 1989, user_id: 2, user: #Ecto.Association.NotLoaded<association :user is not loaded>, inserted_at: ~N[2023-04-12 13:10:21], updated_at: ~N[2023-04-12 13:10:21]}} of type Tuple. This protocol is implemented for the following type(s): Any, Atom, BitString, Float, Integer, Map
        (phoenix 1.7.2) lib/phoenix/param.ex:125: Phoenix.Param.Any.to_param/1
        (market 0.1.0) lib/market_web/components/core_components.ex:475: anonymous fn/4 in MarketWeb.CoreComponents."table (overridable 1)"/1
        (elixir 1.14.2) lib/enum.ex:4307: anonymous fn/3 in Enum.reduce/3
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/live_stream.ex:69: Enumerable.Phoenix.LiveView.LiveStream.do_reduce/3
        (elixir 1.14.2) lib/enum.ex:4307: Enum.reduce/3
        (market 0.1.0) lib/market_web/components/core_components.ex:474: anonymous fn/2 in MarketWeb.CoreComponents."table (overridable 1)"/1
        (market 0.1.0) /Users/x/market/lib/market_web/live/demographic_live/temp_auto_generated/index.html.heex:10: MarketWeb.DemographicLive.Index.render/1
        (elixir 1.14.2) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/diff.ex:396: Phoenix.LiveView.Diff.traverse/7
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/diff.ex:544: anonymous fn/4 in Phoenix.LiveView.Diff.traverse_dynamic/7
        (elixir 1.14.2) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/diff.ex:396: Phoenix.LiveView.Diff.traverse/7
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/diff.ex:139: Phoenix.LiveView.Diff.render/3
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/static.ex:252: Phoenix.LiveView.Static.to_rendered_content_tag/4
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/static.ex:135: Phoenix.LiveView.Static.render/3
        (phoenix_live_view 0.18.18) lib/phoenix_live_view/controller.ex:39: Phoenix.LiveView.Controller.live_render/3
        (phoenix 1.7.2) lib/phoenix/router.ex:430: Phoenix.Router.__call__/5
        (market 0.1.0) lib/market_web/endpoint.ex:9: MarketWeb.Endpoint.plug_builder_call/2

After mix.ecto.reset, some part of the form_component works again as long as commentting out <.input …> fields in the form_component.

8

Hmm, yes I am at version 0.18.18. But it seems to me there is a discrepancy in the way the input component is called, the method you’re showing seems to expect field={f, :gender}, where f is the form, as set with a :let.
I would create a new phx project with the latest version and the same app name in a different folder and see what’s different. Just to save some time.

1 Like
9

Surely, I will try and leave the result here.