Fix breaking with has_many and custom primary key. Fixes #1878

lib/rails_admin/config/actions/index.rb

@@ -49,7 +49,7 @@ class Index < RailsAdmin::Config::Actions::Base
               format.json do
                 output = begin
                   if params[:compact]
-                    primary_key_method = @association ? @association.associated_primary_key : @model_config.abstract_model.primary_key
+                    primary_key_method = @model_config.abstract_model.primary_key
                     label_method = @model_config.object_label_method
                     @objects.collect { |o| {id: o.send(primary_key_method).to_s, label: o.send(label_method).to_s} }
                   else

lib/rails_admin/config/fields/association.rb

@@ -78,7 +78,7 @@ def associated_object_label_method
 
         # Reader for associated primary key
         def associated_primary_key
-          @associated_primary_key ||= association.primary_key
+          @associated_primary_key ||= associated_model_config.abstract_model.primary_key
         end
 
         # Reader for the association's key

spec/controllers/rails_admin/main_controller_spec.rb

@@ -204,14 +204,15 @@ def get(action, params)
   end
 
   describe 'index' do
-    it "uses source association's primary key with :compact, not target model's default primary key", skip_mongoid: true do
+    it "uses target model's primary key", skip_mongoid: true do
+      @player = FactoryBot.create(:player, number: 123)
       class TeamWithNumberedPlayers < Team
         has_many :numbered_players, class_name: 'Player', primary_key: :number, foreign_key: 'team_id'
       end
       FactoryBot.create :team
-      TeamWithNumberedPlayers.first.numbered_players = [FactoryBot.create(:player, number: 123)]
+      TeamWithNumberedPlayers.first.numbered_players = [@player]
       get :index, model_name: 'player', source_object_id: Team.first.id, source_abstract_model: 'team_with_numbered_players', associated_collection: 'numbered_players', current_action: :create, compact: true, format: :json
-      expect(response.body).to match(/\"id\":\"123\"/)
+      expect(response.body).to match(/\"id\":\"#{@player.id}\"/)
     end
 
     context 'as JSON' do

spec/integration/fields/belongs_to_association_spec.rb

@@ -40,4 +40,23 @@
       is_expected.to have_css("a[href='/admin/team/#{@team.id}']")
     end
   end
+
+  context 'with custom primary_key option', active_record: true do
+    let(:user) { FactoryBot.create :user }
+    let!(:teams) { [FactoryBot.create(:team, manager: user.email), FactoryBot.create(:team)] }
+    before do
+      class ManagedTeam < Team
+        belongs_to :user, foreign_key: :manager, primary_key: :email
+      end
+      RailsAdmin.config.included_models = [ManagedTeam]
+      RailsAdmin.config ManagedTeam do
+        field :user
+      end
+    end
+
+    it 'picks up associated primary key correctly' do
+      visit edit_path(model_name: 'managed_team', id: teams[0].id)
+      expect(page).to have_css("select#managed_team_manager option[value=\"#{user.id}\"]")
+    end
+  end
 end

spec/integration/fields/has_many_association_spec.rb

@@ -248,4 +248,34 @@
       is_expected.to have_selector('a.ra-multiselect-item-remove-all')
     end
   end
+
+  context 'with custom primary_key option', active_record: true do
+    let(:user) { FactoryBot.create :user }
+    let!(:teams) { [FactoryBot.create(:team, manager: user.email), FactoryBot.create(:team)] }
+    before do
+      class ManagingUser < User
+        has_many :teams, foreign_key: :manager, primary_key: :email
+      end
+      RailsAdmin.config.included_models = [ManagingUser, Team]
+      RailsAdmin.config ManagingUser do
+        field(:teams) { associated_collection_cache_all false }
+      end
+    end
+
+    it "picks up associated model's primary key correctly" do
+      visit edit_path(model_name: 'managing_user', id: user.id)
+      expect(find("select#managing_user_team_ids option[value=\"#{teams[0].id}\"]")).to have_content teams[0].name
+    end
+
+    it "allows update with fetching associated objects via xhr", js: true do
+      visit edit_path(model_name: 'managing_user', id: user.id)
+      find('input.ra-multiselect-search').set('T')
+      page.execute_script("$('input.ra-multiselect-search').trigger('focus')")
+      page.execute_script("$('input.ra-multiselect-search').trigger('keydown')")
+      find('.ra-multiselect-collection option', text: teams[1].name).select_option
+      find('.ra-multiselect-item-add').click
+      click_button 'Save'
+      expect(ManagingUser.first.teams).to match_array teams
+    end
+  end
 end