Error "must exist" when creating registration in Rails 5.2

Question

I’m creating a Teacher model that has a contact:

ActiveAdmin.register Teacher do
  permit_params :name, :contact_id

form do |f|
    f.semantic_errors *f.object.errors.keys

    f.inputs "Details" do
      f.input :name
      f.input :contact_id, :as => :select, :collection => Contact.all.collect {|contact| [contact.email] }
    end
    f.actions
  end

end

here is the model contact

ActiveAdmin.register Contact do
  permit_params :phone, :email
end

Here is the schema:

ActiveRecord::Schema.define(version: 2019_11_12_175353) do

  create_table "active_admin_comments", force: :cascade do |t|
    t.string "namespace"
    t.text "body"
    t.string "resource_type"
    t.integer "resource_id"
    t.string "author_type"
    t.integer "author_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["author_type", "author_id"], name: "index_active_admin_comments_on_author_type_and_author_id"
    t.index ["namespace"], name: "index_active_admin_comments_on_namespace"
    t.index ["resource_type", "resource_id"], name: "index_active_admin_comments_on_resource_type_and_resource_id"
  end

  create_table "admin_users", force: :cascade do |t|
    t.string "email", default: "", null: false
    t.string "encrypted_password", default: "", null: false
    t.string "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["email"], name: "index_admin_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_admin_users_on_reset_password_token", unique: true
  end

  create_table "contacts", force: :cascade do |t|
    t.string "phone"
    t.string "email"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "groups", force: :cascade do |t|
    t.string "description"
    t.integer "teacher_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["teacher_id"], name: "index_groups_on_teacher_id"
  end

  create_table "students", force: :cascade do |t|
    t.string "name"
    t.integer "teacher_id"
    t.integer "contact_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["contact_id"], name: "index_students_on_contact_id"
    t.index ["teacher_id"], name: "index_students_on_teacher_id"
  end

  create_table "subjects", force: :cascade do |t|
    t.string "description"
    t.integer "teacher_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["teacher_id"], name: "index_subjects_on_teacher_id"
  end

  create_table "teachers", force: :cascade do |t|
    t.string "name"
    t.integer "contact_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["contact_id"], name: "index_teachers_on_contact_id"
  end

end

I’m having a contact error must exist even with contact data appearing on Teacher.

Ruby 2.4, active admin and wicked_pdf, and sqlite, if relevant.

I’ve tried to https://github.com/rails/rails/issues/24518 but does not work, returns another error.

Answer 1

You probably have this error because in select for the :contact_id the id is missing from the collection.

f.input :contact_id, :as => :select, :collection => Contact.all.collect {|contact| [contact.email, contact.id] }

The above code will set the id for each item in the collection. Check the generated HTML for the attribute value is being correctly set to the id of contact.