Support dot notation for :only keys in partial reloads

lib/inertia_rails/renderer.rb

@@ -74,25 +74,21 @@ def merge_props(shared_data, props)
     end
 
     def computed_props
-      _props = merge_props(shared_data, props).select do |key, prop|
-        if rendering_partial_component?
-          partial_keys.none? || key.in?(partial_keys) || prop.is_a?(AlwaysProp)
-        else
-          !prop.is_a?(LazyProp)
-        end
-      end
+      _props = merge_props(shared_data, props)
 
-      drop_partial_except_keys(_props) if rendering_partial_component?
+      deep_transform_props _props do |prop, path|
+        next [:dont_keep] unless keep_prop?(prop, path)
 
-      deep_transform_values _props do |prop|
-        case prop
+        transformed_prop = case prop
         when BaseProp
           prop.call(controller)
         when Proc
           controller.instance_exec(&prop)
         else
           prop
         end
+
+        [:keep, transformed_prop]
       end
     end
 
@@ -105,6 +101,22 @@ def page
       }
     end
 
+    def deep_transform_props(props, parent_path = '', &block)
+      props.reduce({}) do |transformed_props, (key, prop)|
+        current_path = [parent_path, key].reject(&:empty?).join('.')
+
+        if prop.is_a?(Hash)
+          nested = deep_transform_props(prop, current_path, &block)
+          transformed_props.merge!(key => nested) unless nested.empty?
+        else
+          action, transformed_prop = block.call(prop, current_path)
+          transformed_props.merge!(key => transformed_prop) if action == :keep
+        end
+
+        transformed_props
+      end
+    end
+
     def deep_transform_values(hash, &block)
       return block.call(hash) unless hash.is_a? Hash
 
@@ -138,5 +150,35 @@ def resolve_component(component)
 
       configuration.component_path_resolver(path: controller.controller_path, action: controller.action_name)
     end
+
+    def keep_prop?(prop, path)
+      return true if prop.is_a?(AlwaysProp)
+
+      if rendering_partial_component?
+        path_with_prefixes = path_prefixes(path)
+        return false if excluded_by_only_partial_keys?(path_with_prefixes)
+        return false if excluded_by_except_partial_keys?(path_with_prefixes)
+      end
+
+      # Precedence: Evaluate LazyProp only after partial keys have been checked
+      return false if prop.is_a?(LazyProp) && !rendering_partial_component?
+
+      true
+    end
+
+    def path_prefixes(path)
+      parts = path.split('.')
+      (0...parts.length).map do |i|
+        parts[0..i].join('.')
+      end
+    end
+
+    def excluded_by_only_partial_keys?(path_with_prefixes)
+      partial_keys.present? && (path_with_prefixes & partial_keys.map(&:to_s)).empty?
+    end
+
+    def excluded_by_except_partial_keys?(path_with_prefixes)
+      partial_except_keys.present? && (path_with_prefixes & partial_except_keys.map(&:to_s)).any?
+    end
   end
 end

spec/dummy/app/controllers/inertia_render_test_controller.rb

@@ -24,6 +24,30 @@ def except_props
     }
   end
 
+  def deeply_nested_props
+    render inertia: 'TestComponent', props: {
+      flat: 'flat param',
+      lazy: InertiaRails.lazy('lazy param'),
+      nested_lazy: InertiaRails.lazy do
+        {
+          first: 'first nested lazy param',
+        }
+      end,
+      nested: {
+        first: 'first nested param',
+        second: 'second nested param',
+        deeply_nested: {
+          first: 'first deeply nested param',
+          second: false,
+          what_about_nil: nil,
+          deeply_nested_always: InertiaRails.always { 'deeply nested always prop' },
+          deeply_nested_lazy: InertiaRails.lazy { 'deeply nested lazy prop' }
+        }
+      },
+      always: InertiaRails.always { 'always prop' }
+    }
+  end
+
   def view_data
     render inertia: 'TestComponent', view_data: {
       name: 'Brian',

spec/dummy/config/routes.rb

@@ -33,6 +33,7 @@
   get 'always_props' => 'inertia_render_test#always_props'
   get 'except_props' => 'inertia_render_test#except_props'
   get 'non_inertiafied' => 'inertia_test#non_inertiafied'
+  get 'deeply_nested_props' => 'inertia_render_test#deeply_nested_props'
 
   get 'instance_props_test' => 'inertia_rails_mimic#instance_props_test'
   get 'default_render_test' => 'inertia_rails_mimic#default_render_test'

spec/inertia/rendering_spec.rb

@@ -111,6 +111,32 @@
         is_expected.to include('Brandon')
       end
     end
+
+    context 'with dot notation' do
+      let(:headers) do
+        {
+          'X-Inertia' => true,
+          'X-Inertia-Partial-Data' => 'nested.first,nested.deeply_nested.second,nested.deeply_nested.what_about_nil',
+          'X-Inertia-Partial-Component' => 'TestComponent',
+        }
+      end
+
+      before { get deeply_nested_props_path, headers: headers }
+
+      it 'only renders the dot notated props' do
+        expect(response.parsed_body['props']).to eq(
+          'always' => 'always prop',
+          'nested' => {
+            'first' => 'first nested param',
+            'deeply_nested' => {
+              'second' => false,
+              'what_about_nil' => nil,
+              'deeply_nested_always' => 'deeply nested always prop',
+            },
+          },
+        )
+      end
+    end
   end
 
   context 'partial except rendering' do