Do not include variant_unit_with_scale in product update check. When saving products, save variant_unit and variant_unit_scale.

app/assets/javascripts/admin/bulk_product_update.js.coffee

@@ -252,7 +252,7 @@ productsApp.controller "AdminBulkProductsCtrl", [
         url: "/admin/products/bulk_update"
         data: productsToSubmit
       ).success((data) ->
-        if angular.toJson($scope.products) == angular.toJson(data)
+        if angular.toJson($scope.productsWithoutDerivedAttributes()) == angular.toJson(data)
           $scope.resetProducts data
           $scope.displaySuccess()
         else
@@ -266,6 +266,14 @@ productsApp.controller "AdminBulkProductsCtrl", [
       $scope.updateProducts productsToSubmit
 
 
+    $scope.productsWithoutDerivedAttributes = ->
+      products = []
+      if $scope.products
+        products.push angular.extend {}, product for product in $scope.products
+        angular.forEach products, (product) ->
+          delete product.variant_unit_with_scale
+      products
+
     $scope.setMessage = (model, text, style, timeout) ->
       model.text = text
       model.style = style
@@ -354,6 +362,11 @@ filterSubmitProducts = (productsToFilter) ->
         if product.hasOwnProperty("price")
           filteredProduct.price = product.price
           hasUpdatableProperty = true
+        if product.hasOwnProperty("variant_unit_with_scale")
+          match = product.variant_unit_with_scale.match(/^([^_]+)_([\d\.]+)$/)
+          filteredProduct.variant_unit = match[1]
+          filteredProduct.variant_unit_scale = parseFloat(match[2])
+          hasUpdatableProperty = true
         if product.hasOwnProperty("on_hand") and filteredVariants.length == 0 #only update if no variants present
           filteredProduct.on_hand = product.on_hand
           hasUpdatableProperty = true

spec/javascripts/unit/bulk_product_update_spec.js.coffee

@@ -128,9 +128,21 @@ describe "filtering products", ->
       price: 10
     ]
 
+  it 'returns variant_unit_with_scale as variant_unit and variant_unit_scale', ->
+    testProduct =
+      id: 1
+      variant_unit: 'weight'
+      variant_unit_scale: 1
+      variant_unit_with_scale: 'volume_1000'
+
+    expect(filterSubmitProducts([testProduct])).toEqual [
+      id: 1
+      variant_unit: 'volume'
+      variant_unit_scale: 1000
+    ]
   
   # TODO Not an exhaustive test, is there a better way to do this?
-  it "only returns properties the properties of products which ought to be updated", ->
+  it "only returns the properties of products which ought to be updated", ->
     testProduct =
       id: 1
       name: "TestProduct"
@@ -158,11 +170,17 @@ describe "filtering products", ->
         on_hand: 2
         price: 10.0
       ]
+      variant_unit: 'volume'
+      variant_unit_scale: 1
+      variant_unit_name: null
+      variant_unit_with_scale: 'weight_1000'
 
     expect(filterSubmitProducts([testProduct])).toEqual [
       id: 1
       name: "TestProduct"
       supplier_id: 5
+      variant_unit: 'weight'
+      variant_unit_scale: 1000
       available_on: new Date()
       variants_attributes: [
         id: 1
@@ -540,6 +558,23 @@ describe "AdminBulkProductsCtrl", ->
         expect(scope.displayFailure).toHaveBeenCalled()
 
 
+  describe 'fetching products without derived attributes', ->
+    beforeEach ->
+      ctrl "AdminBulkProductsCtrl",
+        $scope: scope
+
+    it 'returns products without the variant_unit_with_scale field', ->
+      scope.products = [{id: 123, variant_unit_with_scale: 'weight_1000'}]
+      expect(scope.productsWithoutDerivedAttributes()).toEqual([{id: 123}])
+
+    it 'returns an empty array when products are undefined', ->
+      expect(scope.productsWithoutDerivedAttributes()).toEqual([])
+
+    it 'does not alter products', ->
+      scope.products = [{id: 123, variant_unit_with_scale: 'weight_1000'}]
+      scope.productsWithoutDerivedAttributes()
+      expect(scope.products).toEqual [{id: 123, variant_unit_with_scale: 'weight_1000'}]
+
 
   describe "deleting products", ->
     beforeEach ->