Ruby on rails 5 问题“集合”未定义方法`to_a' 你的意思是？ to_s

Question

I'm having trouble passing this object to the partial, I can't figure out if the problem is that this project was initially developed on a version of Rails <5 This is the error:

undefined method `to_a' for #EmptySearch:0x00007fd53c037d70 Did you mean? to_s

view:

<div class="col-12 col-lg-8 search-results-container">

  <%#= render partial: 'search_bar' %>
  
  <div class="container-fluid search-results">

    <div class="row py-5" id="search-results">

      <%= render partial: "components/v2/eatery_card", collection: @page.eateries %>

    </div>

  </div>

</div>

the problem occurs to me in this line:

 <%= render partial: "components/v2/eatery_card", collection: @page.eateries %>

this is the controller:

  def show
    redirect_to controller: 'cities', action: 'show', location: searchkick_params[:location] if searchkick_params[:location]
    @page = SearchPage.new(current_user, request, searchkick_params)
    @sarray=@page.eateries

    js search_results: @page.eateries, map_center: @page.map_center, ajax_results_url: api_v1_search_map_results_path, search_allergens: @page.allergen_ids, search_food_typologies: @page.food_typology_ids
  end

render partial:

<div class="col-12 col-md-6">
  <div id="eatery-card" class="eatery_result_<%= eatery_card.id %>">
    <% if signed_in? && current_user.favorite_eateries.ids.include?(eatery_card.id) %>
      <div class="eatery-favorite active eatery_toggle_favorite" data-id="<%= eatery_card.id %>"></div>
    <% else %>
      <div class="eatery-favorite eatery_toggle_favorite" data-id="<%= eatery_card.id %>"></div>
    <% end %>

    <% if @page %>
      <%= link_to '', eatery_path(eatery_card.id, allergens: @page.allergen_ids , food_typologies: @page.food_typology_ids, searched: true), class:'eatery-link' %>
    <% else %>
      <%= link_to '', eatery_path(eatery_card.id), class:'eatery-link' %>
    <% end %>

    <div class="eatery-image" style="background-image: url(<%= eatery_card.image.url(:medium)%>);"></div>

    <h5 class="eatery-name p-0 pt-3 mb-2">
      <%= eatery_card.name %>
      <span class="eatery-category text-success ml-1">
        <%= eatery_card.category.name %>
      </span>
    </h5>
    <h6 class="eatery-address p-0 m-0 mb-2 small"><%= eatery_card.complete_address %></h6>

    <div class="eatery-rating">
      <div class="er-stars mr-1 pull-left">
        <%= rate_to_stars(eatery_card.reviews_score) %>
      </div>
      <span class="er-reviews-count text-muted small"><%= eatery_card.reviews.approved.count %> recensioni</span>
    </div>
  </div>
</div>

EmptySearch class:

class EmptySearch
  def total_count
    0
  end

  def took
    0
  end
end

Answer 1

I'd guess that you're getting an EmptySearch instance from @page.eateries and then you're passing that EmptySearch to something is expected something Enumerable-ish (such as an array, ActiveRecord query, ...), then that something calls to_a to get an array that it can iterate over.

A quick fix is to add to_a to EmptySearch :

class EmptySearch
  #...
  def to_a
    []
  end
end

A better solution would be to make EmptySearch Enumerable. A possibly even better solution would be to get rid of EmptySearch entirely and have @page.eateries give you a query of some sort that doesn't match anything.