From 85ff6fe4a506d34222a7b59b8f4778298e27ee32 Mon Sep 17 00:00:00 2001
From: aharpervc <aharper@breuer.com>
Date: Wed, 24 Oct 2018 16:55:26 -0400
Subject: [PATCH] Fix unhandled exception when starting subtotals with an index
 > 0 - the `collection` is empty and you set `collection[1] = {}`, then
 `collection[0]` will be `nil` and that'll cause things to blow up

---
 lib/data-table/table.rb |  8 ++++++--
 spec/table_spec.rb      | 13 +++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/data-table/table.rb b/lib/data-table/table.rb
index e2c6aa7..d264fab 100644
--- a/lib/data-table/table.rb
+++ b/lib/data-table/table.rb
@@ -339,7 +339,9 @@ def calculate_subtotals!
           @collection.each_pair_with_parents(@groupings.count) do |group_name, group_data, parents|
             path = parents + [group_name]
             result = calculate(group_data, subtotal[0], subtotal[1], path)
-            @subtotal_calculations[path][index] ||= {}
+            (0..index).each do |index|
+              @subtotal_calculations[path][index] ||= {}
+            end
             @subtotal_calculations[path][index][subtotal[0]] = {subtotal[1] => result}
           end
         end
@@ -436,7 +438,9 @@ def calculate_min(collection, column_name)
     def total_row(collection, column_name, function = nil, index = nil, &block)
       function_or_block = function || block
       f = function && block_given? ? [function, block] : function_or_block
-      collection[index] = {} if collection[index].nil?
+      (0..index).each do |index|
+        collection[index] = {} if collection[index].nil?
+      end
       collection[index][column_name] = f
     end
   end
diff --git a/spec/table_spec.rb b/spec/table_spec.rb
index eb60edd..e82e099 100644
--- a/spec/table_spec.rb
+++ b/spec/table_spec.rb
@@ -72,6 +72,19 @@
       expect(data_table.subtotal_calculations).to eq({["Star Wars"]=>[{:power_level=>{:sum=>145.0}}], ["Middle Earth"]=>[{:power_level=>{:sum=>9081.0}}]})
     end
 
+    it "should do sub-totaling starting with indexes > 0" do
+      data_table.group_by :world, level: 0
+      data_table.column :power_level
+      data_table.subtotal :power_level, :sum, 1
+
+      data_table.prepare_data
+
+      expect(data_table.subtotal_calculations).to eq({
+        ["Star Wars"] => [{}, {:power_level => {:sum => 145.0}}],
+        ["Middle Earth"] => [{}, {:power_level => {:sum => 9081.0}}]
+      })
+    end
+
     it "should render a custom header" do
       data_table.custom_header do
         th 'Two Columns', :colspan => 2