Merge pull request #2999 from rs-pro/master

Fix "can't modify frozen array" exception under certain conditions

lib/rails_admin/config/has_fields.rb

@@ -130,7 +130,7 @@ def _fields(readonly = false)
           @_ro_fields = @_fields = RailsAdmin::Config::Fields.factory(self)
         else
           # parent is RailsAdmin::Config::Model, recursion is on Section's classes
-          @_ro_fields ||= parent.send(self.class.superclass.to_s.underscore.split('/').last)._fields(true).freeze
+          @_ro_fields ||= parent.send(self.class.superclass.to_s.underscore.split('/').last)._fields(true).clone.freeze
         end
         readonly ? @_ro_fields : (@_fields ||= @_ro_fields.collect(&:clone))
       end

spec/rails_admin/config_spec.rb

@@ -327,6 +327,44 @@ class RecursivelyEmbedsMany
       end
     end
   end
+
+  describe "field types code reloading" do
+    let(:config) { described_class.model(Team) }
+    let(:fields) { described_class.model(Team).edit.fields }
+
+    let(:team_config) do
+      proc do
+        field :id
+        field :wins, :boolean
+      end
+    end
+    let(:team_config2) do
+      proc do
+        field :wins, :toggle
+      end
+    end
+
+    it "allows code reloading" do
+      Team.send(:rails_admin, &team_config)
+
+      # This simulates the way RailsAdmin really does it
+      config.edit.send(:_fields, true)
+
+      module RailsAdmin
+        module Config
+          module Fields
+            module Types
+              class Toggle < RailsAdmin::Config::Fields::Base
+                RailsAdmin::Config::Fields::Types.register(self)
+              end
+            end
+          end
+        end
+      end
+      Team.send(:rails_admin, &team_config2)
+      expect(fields.map(&:name)).to match_array %i(id wins)
+    end
+  end
 end
 
 module ExampleModule