fix: belongs_to field should use association primary_key

db/factories.rb

@@ -138,12 +138,18 @@
   end
 
   factory :event do
+    uuid { SecureRandom.uuid }
     location { create :location }
     name { Faker::Lorem.sentence }
     event_time { DateTime.now }
     body { Faker::Lorem.paragraphs(number: rand(1...3)).join("\n") }
   end
 
+  factory :volunteer do
+    name { Faker::Name.name }
+    role { Faker::Job.title }
+  end
+
   factory :store do
     name { Faker::Company.name }
     size { ["small", "medium", "large"].sample }

lib/avo/fields/belongs_to_field.rb

@@ -115,6 +115,10 @@ def options
         values_for_type
       end
 
+      def primary_key
+        @primary_key ||= reflection.association_primary_key
+      end
+
       def values_for_type(model = nil)
         resource = target_resource
         resource = Avo.resource_manager.get_resource_by_model_class model if model.present?
@@ -212,12 +216,14 @@ def fill_field(record, key, value, params)
           if valid_model_class.blank? || id_from_param.blank?
             record.send(:"#{polymorphic_as}_id=", nil)
           else
-            record_id = target_resource(record:, polymorphic_model_class: value.safe_constantize).find_record(id_from_param).id
+            record_id = target_resource(record:, polymorphic_model_class: value.safe_constantize)
+              .find_record(id_from_param)
+              .send(primary_key.presence || :id)
 
             record.send(:"#{polymorphic_as}_id=", record_id)
           end
         else
-          record_id = value.blank? ? value : target_resource(record:).find_record(value).id
+          record_id = value.blank? ? value : target_resource(record:).find_record(value).send(primary_key.presence || :id)
 
           record.send(:"#{key}=", record_id)
         end

spec/dummy/app/avo/resources/volunteer.rb

@@ -0,0 +1,8 @@
+class Avo::Resources::Volunteer < Avo::BaseResource
+  def fields
+    field :id, as: :id
+    field :name, as: :text
+    field :role, as: :text
+    field :event, as: :belongs_to, foreign_key: :event_uuid, primary_key: :uuid, placeholder: "—"
+  end
+end

spec/dummy/app/controllers/avo/volunteers_controller.rb

@@ -0,0 +1,4 @@
+# This controller has been generated to enable Rails' resource routes.
+# More information on https://docs.avohq.io/3.0/controllers.html
+class Avo::VolunteersController < Avo::ResourcesController
+end

spec/dummy/app/models/event.rb

@@ -14,7 +14,7 @@ class Event < ApplicationRecord
   has_rich_text :body
 
   belongs_to :location, optional: true
-
+  has_many :volunteers, foreign_key: :event_uuid, primary_key: :uuid
   has_one_attached :profile_photo
   has_one_attached :cover_photo
 

spec/dummy/app/models/volunteer.rb

@@ -0,0 +1,3 @@
+class Volunteer < ApplicationRecord
+  belongs_to :event, foreign_key: "event_uuid", primary_key: "uuid"
+end

spec/dummy/db/migrate/20250310175239_add_uuid_to_events.rb

@@ -0,0 +1,6 @@
+class AddUuidToEvents < ActiveRecord::Migration[6.1]
+  def change
+    add_column :events, :uuid, :uuid
+    add_index :events, :uuid, unique: true
+  end
+end

spec/dummy/db/migrate/20250310175357_create_volunteers.rb

@@ -0,0 +1,12 @@
+class CreateVolunteers < ActiveRecord::Migration[6.1]
+  def change
+    create_table :volunteers do |t|
+      t.string :name
+      t.string :role
+      t.uuid :event_uuid, null: false
+
+      t.timestamps
+    end
+    add_index :volunteers, :event_uuid
+  end
+end

spec/dummy/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_01_03_192051) do
+ActiveRecord::Schema[8.0].define(version: 2025_03_10_175357) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
 
@@ -114,7 +114,9 @@
     t.datetime "updated_at", null: false
     t.text "body"
     t.bigint "location_id"
+    t.uuid "uuid"
     t.index ["location_id"], name: "index_events_on_location_id"
+    t.index ["uuid"], name: "index_events_on_uuid", unique: true
   end
 
   create_table "fish", force: :cascade do |t|
@@ -297,6 +299,15 @@
     t.index ["team_id"], name: "index_users_on_team_id"
   end
 
+  create_table "volunteers", force: :cascade do |t|
+    t.string "name"
+    t.string "role"
+    t.uuid "event_uuid", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["event_uuid"], name: "index_volunteers_on_event_uuid"
+  end
+
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
   add_foreign_key "comments", "users"

spec/features/avo/belongs_to_spec.rb

@@ -159,6 +159,21 @@
     end
   end
 
+  describe "with custom primary key set" do
+    let(:event) { create(:event, name: "Sample Event") }
+
+    let!(:volunteer) { create(:volunteer, event_uuid: event.uuid) }
+
+    it "displays the event link using the UUID and stores the correct foreign key" do
+      visit "/admin/resources/volunteers/#{volunteer.id}"
+
+      expect(page).to have_link event.name, href: "/admin/resources/events/#{event.id}?via_record_id=#{volunteer.id}&via_resource_class=Avo%3A%3AResources%3A%3AVolunteer"
+
+      expect(volunteer.event_uuid).to eq(event.uuid)
+      expect(volunteer.event).to eq(event)
+    end
+  end
+
   describe "hidden columns if current polymorphic association" do
     let!(:user) { create :user }
     let!(:project) { create :project, name: "Haha project" }