Allow a V2 view to specify its parent, regardless of how it's nested

lib/blueprinter/v2/dsl.rb

@@ -8,12 +8,13 @@ module DSL
       # Define a new child view, which is a subclass of self.
       #
       # @param name [Symbol] Name of the view
+      # @param inherit [Symbol] Name of view to inherit from (default is the immediate inherit)
       # @yield Define the view in the block
       #
-      def view(name, &definition)
+      def view(name, inherit: nil, &definition)
         raise Errors::InvalidBlueprint, "View name may not contain '.'" if name.to_s =~ /\./
 
-        views[name.to_sym] = definition
+        views[name.to_sym] = ViewBuilder::Definition.new(definition, inherit)
       end
 
       #

lib/blueprinter/v2/view_builder.rb

@@ -11,6 +11,8 @@ module V2
     class ViewBuilder
       include Enumerable
 
+      Definition = Struct.new(:definition, :parent_override)
+
       # @param parent [Class] A subclass of Blueprinter::V2::Base
       def initialize(parent)
         @parent = parent
@@ -23,7 +25,7 @@ def initialize(parent)
       # Add a view definition.
       #
       # @param name [Symbol]
-      # @param definition [Proc]
+      # @param definition [Blueprinter::V2::ViewBuilder::Definition]
       #
       def []=(name, definition)
         @pending[name.to_sym] = definition
@@ -37,13 +39,15 @@ def []=(name, definition)
       #
       def [](name)
         name = name.to_sym
-        if [email protected]?(name) and @pending.key?(name)
+        if [email protected]?(name) and (pending = @pending[name])
+          parent = pending.parent_override ? root_blueprint[pending.parent_override] : @parent
+
           @mut.synchronize do
             next if @views.key?(name)
 
-            view = Class.new(@parent)
+            view = Class.new(parent)
             view.append_name(name)
-            view.class_eval(&@pending[name]) if @pending[name]
+            view.class_eval(&pending.definition) if pending.definition
             view.eval!(false)
             @views[name] = view
           end
@@ -63,6 +67,18 @@ def each(&block)
         end
         block ? enum.each(&block) : enum
       end
+
+      private
+
+      # Finds and returns the "root" blueprint view class (i.e. one named :default).
+      # The view "inherit" option needs this so it can inherit using a fully-qualified view name.
+      def root_blueprint
+        return @root_blueprint if @root_blueprint
+
+        blueprint = @parent
+        blueprint = blueprint.superclass until blueprint.view_name == :default
+        @root_blueprint = blueprint
+      end
     end
   end
 end

spec/v2/view_builder_spec.rb

@@ -19,22 +19,24 @@
 
   it "should store, but not evaluate, a view" do
     calls = 0
-    builder[:foo] =
+    builder[:foo] = Blueprinter::V2::ViewBuilder::Definition.new(
       proc do
         field :description
         calls += 1
       end
+    )
 
     expect(calls).to eq 0
   end
 
   it "should evaluate a view on first access" do
     calls = 0
-    builder[:foo] =
+    builder[:foo] = Blueprinter::V2::ViewBuilder::Definition.new(
       proc do
         field :description
         calls += 1
       end
+    )
 
     view = builder[:foo]
     builder[:foo]
@@ -43,7 +45,7 @@
   end
 
   it "should fetch a view" do
-    builder[:foo] = proc { field :description }
+    builder[:foo] = Blueprinter::V2::ViewBuilder::Definition.new(proc { field :description })
 
     view = builder.fetch(:foo)
     expect(view.reflections[:default].fields.keys.sort).to eq %i(id name description).sort
@@ -54,10 +56,33 @@
   end
 
   it "should iterate over each view" do
-    builder[:foo] = proc { field :description }
-    builder[:bar] = proc { field :description }
+    builder[:foo] = Blueprinter::V2::ViewBuilder::Definition.new(proc { field :description })
+    builder[:bar] = Blueprinter::V2::ViewBuilder::Definition.new(proc { field :description })
 
     keys = builder.each.map { |name, _| name }
     expect(keys.sort).to eq %i(default foo bar).sort
   end
+
+  it 'should inherit from a different parent' do
+    blueprint = Class.new(Blueprinter::V2::Base) do
+      view :normal do
+        field :foo
+      end
+
+      view :normal2, inherit: :normal do
+        field :foo2
+      end
+
+      view :expanded do
+        field :bar
+
+        view :foo, inherit: :normal do
+          field :foo2
+        end
+      end
+    end
+
+    expect(blueprint.reflections[:normal2].fields.keys).to eq %i(foo foo2)
+    expect(blueprint.reflections[:"expanded.foo"].fields.keys).to eq %i(foo foo2)
+  end
 end