Use form hash structure

The array format is generally fine, but to properly support checkboxes, we need this format with hash keys.
https://guides.rubyonrails.org/form_helpers.html#understanding-parameter-naming-conventions

app/reflexes/products_reflex.rb

@@ -167,18 +167,26 @@ class ProductsReflex < ApplicationReflex
     # Form field names:
     #   '[products][0][id]' (hidden field)
     #   '[products][0][name]'
+    #   '[products][0][variants_attributes][0][id]' (hidden field)
+    #   '[products][0][variants_attributes][0][display_name]'
     #
     # Resulting in params:
     #     "products" => {
-    #       "<i>" =>  {
+    #       "0" =>  {
     #         "id" => "123"
     #         "name" => "Pommes",
+    #         "variants_attributes" => {
+    #           "0" => {
+    #           "id" => "1234",
+    #           "display_name" => "Large box",
+    #         }
     #       }
     #     }
-
-    collection_hash = products_bulk_params[:products].each_with_index
-      .to_h { |p, i|
-        [i, p]
+    collection_hash = products_bulk_params[:products]
+      .transform_values { |product|
+        # Convert variants_attributes form hash to an array if present
+        product[:variants_attributes] &&= product[:variants_attributes].values
+        product
       }.with_indifferent_access
     Sets::ProductSet.new(collection_attributes: collection_hash)
   end

app/views/admin/products_v3/_table.html.haml

@@ -38,8 +38,8 @@
         %th.align-left= t('admin.products_page.columns.tax_category')
         %th.align-left= t('admin.products_page.columns.inherits_properties')
         %th.align-right= t('admin.products_page.columns.actions')
-    - products.each do |product|
-      = form.fields_for("products", product, index: nil) do |product_form|
+    - products.each_with_index do |product, product_index|
+      = form.fields_for("products", product, index: product_index) do |product_form|
         %tbody.relaxed{ 'data-record-id': product_form.object.id }
           %tr
             %td.field.align-left.header
@@ -70,8 +70,8 @@
                 = link_to t('admin.products_page.actions.edit'), edit_admin_product_path(product)
                 = link_to t('admin.products_page.actions.clone'), clone_admin_product_path(product)
 
-          - product.variants.each do |variant|
-            = form.fields_for("products][][variants_attributes][", variant, index: nil) do |variant_form|
+          - product.variants.each_with_index do |variant, variant_index|
+            = form.fields_for("products][#{product_index}][variants_attributes][", variant, variant_index:) do |variant_form|
               %tr.condensed
                 %td.field
                   = variant_form.hidden_field :id

spec/reflexes/products_reflex_spec.rb

@@ -39,14 +39,14 @@ describe ProductsReflex, type: :reflex, feature: :admin_style_v3 do
 
     it "saves valid changes" do
       params = {
-        # '[products][][name]'
-        "products" => [
-          {
+        # '[products][0][name]'
+        "products" => {
+          "0" => {
             "id" => product_a.id.to_s,
             "name" => "Pommes",
             "sku" => "POM-00",
-          }
-        ]
+          },
+        },
       }
 
       expect{
@@ -57,24 +57,27 @@ describe ProductsReflex, type: :reflex, feature: :admin_style_v3 do
     end
 
     it "saves valid changes to products and nested variants" do
+      # Form field names:
+      #   '[products][0][id]' (hidden field)
+      #   '[products][0][name]'
+      #   '[products][0][variants_attributes][0][id]' (hidden field)
+      #   '[products][0][variants_attributes][0][display_name]'
       params = {
-        # '[products][][name]'
-        # '[products][][variants_attributes][][display_name]'
-        "products" => [
-          {
+        "products" => {
+          "0" => {
             "id" => product_a.id.to_s,
             "name" => "Pommes",
-            "variants_attributes" => [
-              {
+            "variants_attributes" => {
+              "0" => {
                 "id" => variant_a1.id.to_s,
                 "display_name" => "Large box",
                 "sku" => "POM-01",
                 "price" => "10.25",
                 "on_hand" => "6",
-              }
-            ],
-          }
-        ]
+              },
+            },
+          },
+        },
       }
 
       expect{
@@ -91,15 +94,15 @@ describe ProductsReflex, type: :reflex, feature: :admin_style_v3 do
     describe "sorting" do
       let(:params) {
         {
-          "products" => [
-            {
+          "products" => {
+            "0" => {
               "id" => product_a.id.to_s,
               "name" => "Pommes",
             },
-            {
+            "1" => {
               "id" => product_b.id.to_s,
             },
-          ]
+          },
         }
       }
       subject{ run_reflex(:bulk_update, params:) }
@@ -115,20 +118,20 @@ describe ProductsReflex, type: :reflex, feature: :admin_style_v3 do
     describe "error messages" do
       it "summarises error messages" do
         params = {
-          "products" => [
-            {
+          "products" => {
+            "0" => {
               "id" => product_a.id.to_s,
               "name" => "Pommes",
             },
-            {
+            "1" => {
               "id" => product_b.id.to_s,
               "name" => "", # Name can't be blank
             },
-            {
+            "2" => {
               "id" => product_c.id.to_s,
               "name" => "", # Name can't be blank
             },
-          ]
+          },
         }
 
         reflex = run_reflex(:bulk_update, params:)

spec/system/admin/products_v3/products_spec.rb

@@ -225,8 +225,7 @@ describe 'As an admin, I can see the new product page', feature: :admin_style_v3
         .and change{ variant_a1.sku }.to("POM-01")
         .and change{ variant_a1.price }.to(10.25)
         .and change{ variant_a1.on_hand }.to(6)
-      pending "Array parameters do not play well with the check_box helper."
-        # .and change{ variant_a1.on_demand }.to(true)
+        .and change{ variant_a1.on_demand }.to(true)
 
       within row_containing_name("Pommes") do
         expect(page).to have_field "Name", with: "Pommes"