Omit meaningless markup from hidden input in core components

[bopm]

Motivation

The current version of core components given

<.input type="hidden" field={@form[:user_id]} value={@current_user.id} />

produces next markup

<div phx-feedback-for="message[user_id]" data-phx-id="..." class="phx-no-feedback">
  <label for="message_user_id" class="block text-sm font-semibold leading-6 text-zinc-800" data-phx-id="..."></label>
  <input type="hidden" name="message[user_id]" id="message_user_id" value="2" 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 border-zinc-300 focus:border-zinc-400">
</div>

Most of that is completely meaningless for hidden fields.

Change

After implementing these changes, it'll generate next markup:

<input type="hidden" name="message[user_id]" id="message_user_id" value="2" data-phx-id="...">

[Gazler]

We probably want a {@rest} in here to capture any additional provided attributes.

[bopm]

Rest consists of things that should not be in hidden input as well. At least to my understanding. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/hidden

[SteffenDE]

Passing something like form can still be relevant for hidden inputs, therefore rest should be included in my opinion.

[bopm]

Added.

[josevalim]

For what is worth, I don’t think we should support :hidden through <.input. Instead, I would just write the input directly.

[josevalim]

In other words, I would remove hidden from here: https://github.com/phoenixframework/phoenix/blob/main/priv/templates/phx.gen.live/core_components.ex#L277

[josevalim]

We should remove radio as well to solve #5506 .

[bopm]

For what is worth, I don’t think we should support :hidden through <.input. Instead, I would just write the input directly.

I tried it too, leading to an unsafe input error. I am AFK to reproduce that error exactly, but it is something like that.

[bopm]

Yep, the exact error is

Phoenix.HTML.Safe not implemented for %Phoenix.HTML.FormField

[SteffenDE]

@bopm you will have to do something like this when using <input> directly:

<input type="hidden" id={@form[:field].id} name={@form[:field].name} value={@form[:field}.value} />

You cannot pass the form field to a plain input tag, that's where the error comes from.

[bopm]

@SteffenDE That works, but do I understand correctly that this way I am losing things like Phoenix.HTML.Form.normalize_value?

[SteffenDE]

That's right, but normalize_value does nothing for "hidden" inputs anyway. As this PR is only about what is generated in new applications, you can of course keep the "hidden" case for the <.input> component in your app. That's what I do as well, as I see a benefit in not always writing out the attributes.

[bopm]

That makes sense too, my other concern is that this general approach that @josevalim is offering will push developers to remember that some field types require different notation than others. For me, don't make me think feels like a better approach, as Phoenix is already complex enough, but I am unsure if I am getting it all right.

[josevalim]

I squeezed it all into a one liner, so maybe it is more amenable for merging.