Validation errors are not displaying at multipart form in rails

Question

I have a model BookingPost that has many Reservations. In booking_posts/show.html.erb I have:

<div class="card-action">
          <%= form_for([@reservation.booking_post, @reservation], html: {multipart: true}, class: "col s12") do |f| %>
          <% if @reservation.errors.any? %>
            <div id="error_explanation">
              <h2><%= pluralize(@reservation.errors.count, "error") %> prohibited this post from being saved:</h2>

              <ul>
              <% @reservation.errors.full_messages.each do |message| %>
                <li><%= message %></li>
              <% end %>
              </ul>
            </div>
          <% end %>

          <div class="col s6">
            <%= f.label :start %>
            <%= f.date_field :start, placeholder: "start time",  class: "datepicker" %>
          </div>
          <div class="col s6">
            <%= f.label :end %>
            <%= f.date_field :end, placeholder: "end time",  class: "datepicker" %>
          </div>
          <div class="col s6">
            <%= f.label :reservation_time %>
            <%= f.time_field :reservation_time, placeholder: "time", class: "timepicker", id: "timepicker", type: "time" %>
          </div>

          <div class="input-field col s6">
            <%= f.label :name %>
            <%= f.text_field :name, class: "validate" %>
          </div>
          <div class="input-field col s6">
            <%= f.label :email %>
            <%= f.text_field :email, class: "validate" %>
          </div>
          <div class="input-field col s6">
            <%= f.label :phone_number %>
            <%= f.text_field :phone_number, class: "validate" %>
          </div>

          <div class="waves-effect waves-light btn">
            <%= f.submit t(:submit_reservation)%>
          </div>  

        <% end %>
        <br>
        </div>   

booking_posts_controller:

  # GET /booking_posts/1
  # GET /booking_posts/1.json
  def show
    @booking_picture = @booking_post.booking_pictures.build
    @booking_pictures = @booking_post.booking_pictures
    @reservation = @booking_post.reservations.build
    @reservations = @booking_post.reservations
  end

reservations_controller:

  # GET /reservations/new
  def new
    @reservation = Reservation.new
  end

  def create
    @booking_post = BookingPost.find(params[:booking_post_id])
    @email= User.where(admin: true).first.email
    @reservation = @booking_post.reservations.build(reservation_params)

    respond_to do |format|
      if @reservation.save
        @saved_reservation = @reservation
        format.html { redirect_to :back, notice: 'Reservation was successfully created.' }
        format.json { render :show, status: :created, location: @reservation }
        ReservationMailer.fresh_message(@saved_reservation, @email).deliver_now
      else
        format.html {redirect_to :back
        flash[:info] = @reservation.errors.full_messages do |m|
          m
        end}
        format.json { render json: @reservation.errors, status: :unprocessable_entity }
      end
    end
  end

But I can't see any validation errors, even like presence: true. Seems like I don't have correct @reservation, because I have a deal with Array in my form_for. Help me please to solve this issue, thanks!

Answer 1

The reason you are not seeing validation errors is because you are issuing a redirect_to :back when validations fails instead of rendering :new action which already includes any errors you might have inside the @reservation instance object.

Also you were trying to add the error messages into the flash message while trying to display them using the @reservation object.

this should be the correct else clause

  else
    format.html { render :new }
    format.json { render json: @reservation.errors, status: :unprocessable_entity }
  end