Why does Phoenix Core Components generate an inner_block that's not used?

Hi all,

Using the latest phx_new (1.7.12), when a new project is generated, the input/1 function in core_components.ex declares a slot :inner_block, but then does not use this block anywhere in the following function clauses, at least not in an obvious way if it is being used. I’m just trying to understand if this is a mistake or oversight, or is it intentional? If so, why? As far as I can tell all this does is silently swallow the error if you do happen to pass a block to <.input>, which seems… Undesirable. I’m happy to submit a PR removing this from the generators if it’s accidental, and if it’s not accidental perhaps a comment explaining the purpose.

If you need to refresh your memory, here’s the entire input/1 definition from a freshly generated Phoenix 1.7.12 project:

  attr :id, :any, default: nil
  attr :name, :any
  attr :label, :string, default: nil
  attr :value, :any

  attr :type, :string,
    default: "text",
    values: ~w(checkbox color date datetime-local email file month number password
               range search select tel text textarea time url week)

  attr :field, Phoenix.HTML.FormField,
    doc: "a form field struct retrieved from the form, for example: @form[:email]"

  attr :errors, :list, default: []
  attr :checked, :boolean, doc: "the checked flag for checkbox inputs"
  attr :prompt, :string, default: nil, doc: "the prompt for select inputs"
  attr :options, :list, doc: "the options to pass to Phoenix.HTML.Form.options_for_select/2"
  attr :multiple, :boolean, default: false, doc: "the multiple flag for select inputs"

  attr :rest, :global,
    include: ~w(accept autocomplete capture cols disabled form list max maxlength min minlength
                multiple pattern placeholder readonly required rows size step)

  slot :inner_block

  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

  def input(%{type: "checkbox"} = assigns) do
    assigns =
      assign_new(assigns, :checked, fn ->
        Phoenix.HTML.Form.normalize_value("checkbox", assigns[:value])
      end)

    ~H"""
    <div phx-feedback-for={@name}>
      <label class="flex items-center gap-4 text-sm leading-6 text-zinc-600">
        <input type="hidden" name={@name} value="false" />
        <input
          type="checkbox"
          id={@id}
          name={@name}
          value="true"
          checked={@checked}
          class="rounded border-zinc-300 text-zinc-900 focus:ring-0"
          {@rest}
        />
        <%= @label %>
      </label>
      <.error :for={msg <- @errors}><%= msg %></.error>
    </div>
    """
  end

  def input(%{type: "select"} = assigns) do
    ~H"""
    <div phx-feedback-for={@name}>
      <.label for={@id}><%= @label %></.label>
      <select
        id={@id}
        name={@name}
        class="mt-2 block w-full rounded-md border border-gray-300 bg-white shadow-sm focus:border-zinc-400 focus:ring-0 sm:text-sm"
        multiple={@multiple}
        {@rest}
      >
        <option :if={@prompt} value=""><%= @prompt %></option>
        <%= Phoenix.HTML.Form.options_for_select(@options, @value) %>
      </select>
      <.error :for={msg <- @errors}><%= msg %></.error>
    </div>
    """
  end

  def input(%{type: "textarea"} = assigns) do
    ~H"""
    <div phx-feedback-for={@name}>
      <.label for={@id}><%= @label %></.label>
      <textarea
        id={@id}
        name={@name}
        class={[
          "mt-2 block w-full rounded-lg text-zinc-900 focus:ring-0 sm:text-sm sm:leading-6",
          "min-h-[6rem] phx-no-feedback:border-zinc-300 phx-no-feedback:focus:border-zinc-400",
          @errors == [] && "border-zinc-300 focus:border-zinc-400",
          @errors != [] && "border-rose-400 focus:border-rose-400"
        ]}
        {@rest}
      ><%= Phoenix.HTML.Form.normalize_value("textarea", @value) %></textarea>
      <.error :for={msg <- @errors}><%= msg %></.error>
    </div>
    """
  end

  # All other inputs text, datetime-local, url, password, etc. are handled here...
  def input(assigns) do
    ~H"""
    <div phx-feedback-for={@name}>
      <.label for={@id}><%= @label %></.label>
      <input
        type={@type}
        name={@name}
        id={@id}
        value={Phoenix.HTML.Form.normalize_value(@type, @value)}
        class={[
          "mt-2 block w-full rounded-lg text-zinc-900 focus:ring-0 sm:text-sm sm:leading-6",
          "phx-no-feedback:border-zinc-300 phx-no-feedback:focus:border-zinc-400",
          @errors == [] && "border-zinc-300 focus:border-zinc-400",
          @errors != [] && "border-rose-400 focus:border-rose-400"
        ]}
        {@rest}
      />
      <.error :for={msg <- @errors}><%= msg %></.error>
    </div>
    """
  end