Prompt appears for only 2 of 3 Rails form (collection

I'm a Rails beginner. I have a form with several collection_select elements (Category, Bank Account, Vendor). The fields for Category and Bank Account correctly display the supplied prompt, but the Vendor field does not display its prompt. Instead the first Vendor is shown, and the prompt does not appear in that drop down list at all.

I'm very confused because the Bank Account field is very similar but it works correctly.

Here's a picture:

app/views/register_transactions/new.html.erb

<div>
   <h1>New Register Transaction</h1>
   <%= render 'form', register_transaction: @register_transaction %>
</div>

app/views/register_transactions/_form.html.erb

<%= form_with(model: @register_transaction) do |f| %>

  <%= f.label :date %>
  <%= f.date_field :date %>

  <%= f.label :category_id %>
  <%= f.grouped_collection_select(:category_id, 
                                  Category.top_level, 
                                  :subcategories, 
                                  :name, 
                                  :id, 
                                  :name,
                                  { prompt: 'Select a category'}) %>

  <%= f.label :vendor_id %>
  <%= f.collection_select :vendor_id, 
                          Vendor.order(:name), 
                          :id, 
                          :name, 
                          {prompt: 'Select a vendor'} %>

  <%= f.label :amount %>
  <%= f.text_field :amount %>

  <%= f.label :bank_account_id%>
  <%= f.collection_select :bank_account_id, 
                          BankAccount.order(:name), 
                          :id, 
                          :name, 
                          {prompt: 'Select an account'} %>

  <%= f.label :memo %>
  <%= f.text_field :memo %>

  <%= f.submit %>
<% end %>

app/controllers/register_transactions_controller.rb

class RegisterTransactionsController < ApplicationController

  ... abbrieviated...

  def new
    @register_transaction = RegisterTransaction.new
  end
  
  private
    def register_transaction_params
      params.require(:register_transaction).permit(:date, :category_id, :vendor_id, :amount, :bank_account_id, :memo)
    end
end

app/models/vendor.rb

class Vendor < ApplicationRecord
  validates :name, uniqueness: true, presence: true
  has_many :register_transactions, dependent: :nullify
end

app/models/bank_account.rb

class BankAccount < ApplicationRecord
  ACCOUNT_TYPES = %w(On-Budget Off-Budget Closed).freeze
  validates :name, uniqueness: true, presence: true
  validates :account_type, presence: true
  validates :account_type, inclusion: ACCOUNT_TYPES
  has_many :register_transactions, dependent: :nullify
  attr_accessor :date

end

app/models/category.rb

class Category < ApplicationRecord
  belongs_to :parent, class_name: "Category", optional: true
  has_many :subcategories, class_name: "Category", foreign_key: :parent_id
  scope :top_level, -> { where(parent_id: nil) }

  validates :name, uniqueness: true, presence: true

  has_many :budget_transactions, dependent: :nullify
  has_many :register_transactions, dependent: :nullify

end

The server response when I load the page 'register_transactions/new'

Started GET "/register_transactions/new" for 127.0.0.1 at 2022-05-28 17:41:08 -0700
Processing by RegisterTransactionsController#new as HTML
  Rendering layout layouts/application.html.erb
  Rendering register_transactions/new.html.erb within layouts/application
  Category Load (0.3ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" IS NULL
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.2ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 1]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.1ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 2]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.2ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 3]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.2ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 4]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.1ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 5]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (1.8ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 6]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.1ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 7]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.3ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 8]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Category Load (0.1ms)  SELECT "categories".* FROM "categories" WHERE "categories"."parent_id" = ?  [["parent_id", 9]]
  ↳ app/views/register_transactions/_form.html.erb:7
  Vendor Load (0.3ms)  SELECT "vendors".* FROM "vendors" ORDER BY "vendors"."name" ASC
  ↳ app/views/register_transactions/_form.html.erb:16
  BankAccount Load (0.3ms)  SELECT "bank_accounts".* FROM "bank_accounts" ORDER BY "bank_accounts"."name" ASC
  ↳ app/views/register_transactions/_form.html.erb:26
  Rendered register_transactions/_form.html.erb (Duration: 35.7ms | Allocations: 15908)
  Rendered register_transactions/new.html.erb within layouts/application (Duration: 36.9ms | Allocations: 16216)
  Rendered layout layouts/application.html.erb (Duration: 40.3ms | Allocations: 18683)
Completed 200 OK in 43ms (Views: 38.4ms | ActiveRecord: 4.1ms | Allocations: 19653)

CodePudding user response：

prompt text is only shown if there is no value set for the attribute. You can check if there is any default value set to the vendor_id.