Add lazy evaluation for data via read_value

Author: goosys

lib/administrate/field/base.rb

@@ -65,18 +65,22 @@ def self.local_partial_prefixes(look: :default)
         end
       end
 
-      def initialize(attribute, data, page, options = {})
+      def initialize(attribute, raw_data, page, options = {})
         @attribute = attribute
         @page = page
         @resource = options.delete(:resource)
         @options = options
-        @data = read_value(data)
+        @raw_data = raw_data
       end
 
       def html_class
         self.class.html_class
       end
 
+      def data
+        read_value(@raw_data)
+      end
+
       def html_controller
         nil
       end
@@ -133,7 +137,7 @@ def required?
         end
       end
 
-      attr_reader :attribute, :data, :options, :page, :resource
+      attr_reader :attribute, :options, :page, :resource
       attr_accessor :context
     end
   end

lib/administrate/field/has_many.rb

@@ -78,7 +78,7 @@ def more_than_limit?
       end
 
       def data
-        @data ||= associated_class.none
+        super || associated_class.none
       end
 
       def order_from_params(params)

spec/lib/fields/base_spec.rb

@@ -300,5 +300,15 @@
         expect(field.data).to eq(nil)
       end
     end
+
+    context "when context is set and a getter block is provided" do
+      it "lazily reads the value from the context" do
+        resource = double("Model")
+        field = field_class.new(:attribute, :date, :page, resource: resource, getter: ->(f) { f.context.custom_value + " from block" })
+        field.context = double("Context", custom_value: "custom value")
+
+        expect(field.data).to eq("custom value from block")
+      end
+    end
   end
 end