Exclude canceled inventory units from Shipment#to_package

core/app/models/spree/shipment.rb

@@ -262,7 +262,9 @@ def tax_total
     def to_package
       package = Stock::Package.new(stock_location)
       package.shipment = self
-      inventory_units.includes(variant: :product).joins(:variant).group_by(&:state).each do |state, state_inventory_units|
+      # Canceled units must not contribute to shipping rate calculation: every
+      # caller of this method feeds the result to the shipping estimator/calculators.
+      inventory_units.not_canceled.includes(variant: :product).joins(:variant).group_by(&:state).each do |state, state_inventory_units|
         package.add_multiple state_inventory_units, state.to_sym
       end
       package

core/spec/models/spree/shipment_spec.rb

@@ -304,7 +304,7 @@
         before do
           allow(line_item).to receive(:order) { order }
           shipment.inventory_units = inventory_units
-          allow(shipment.inventory_units).to receive_message_chain(:includes, :joins).and_return inventory_units
+          allow(shipment.inventory_units).to receive_message_chain(:not_canceled, :includes, :joins).and_return inventory_units
         end
 
         it "should use symbols for states when adding contents to package" do
@@ -316,6 +316,20 @@
         it "should set the shipment to itself" do
           expect(shipment.to_package.shipment).to eq(shipment)
         end
+
+        context "with a canceled inventory unit on the shipment" do
+          let(:order_with_units) { create(:order_ready_to_ship, line_items_count: 2) }
+          let(:real_shipment) { order_with_units.shipments.first }
+
+          it "excludes canceled inventory units from the package" do
+            kept_unit, canceled_unit = real_shipment.inventory_units.to_a
+            canceled_unit.update_columns(state: "canceled")
+
+            package = real_shipment.to_package
+
+            expect(package.contents.map(&:inventory_unit)).to contain_exactly(kept_unit)
+          end
+        end
       end
     end
   end