Add version to auditable_index

CHANGELOG.md

@@ -15,7 +15,8 @@ Added
 
 Changed
 
-- None
+- Add version to auditable_index
+  [#427](https://github.com/collectiveidea/audited/pull/427)
 
 Fixed
 

lib/audited/audit.rb

@@ -171,7 +171,7 @@ def self.collection_cache_key(collection = all, timestamp_column = :created_at)
     private
 
     def set_version_number
-      max = self.class.auditable_finder(auditable_id, auditable_type).descending.first.try(:version) || 0
+      max = self.class.auditable_finder(auditable_id, auditable_type).maximum(:version) || 0
       self.version = max + 1
     end
 

lib/generators/audited/templates/add_version_to_auditable_index.rb

@@ -0,0 +1,21 @@
+class <%= migration_class_name %> < <%= migration_parent %>
+  def self.up
+    if index_exists?(:audits, [:auditable_type, :auditable_id], name: index_name)
+      remove_index :audits, name: index_name
+      add_index :audits, [:auditable_type, :auditable_id, :version], name: index_name
+    end
+  end
+
+  def self.down
+    if index_exists?(:audits, [:auditable_type, :auditable_id, :version], name: index_name)
+      remove_index :audits, name: index_name
+      add_index :audits, [:auditable_type, :auditable_id], name: index_name
+    end
+  end
+
+  private
+
+  def index_name
+    'auditable_index'
+  end
+end

lib/generators/audited/templates/install.rb

@@ -17,7 +17,7 @@ def self.up
       t.column :created_at, :datetime
     end
 
-    add_index :audits, [:auditable_type, :auditable_id], :name => 'auditable_index'
+    add_index :audits, [:auditable_type, :auditable_id, :version], :name => 'auditable_index'
     add_index :audits, [:associated_type, :associated_id], :name => 'associated_index'
     add_index :audits, [:user_id, :user_type], :name => 'user_index'
     add_index :audits, :request_uuid

lib/generators/audited/upgrade_generator.rb

@@ -58,6 +58,10 @@ def migrations_to_be_applied
         if indexes.any? { |i| i.columns == %w[associated_id associated_type] }
           yield :revert_polymorphic_indexes_order
         end
+
+        if indexes.any? { |i| i.columns == %w[auditable_type auditable_id] }
+          yield :add_version_to_auditable_index
+        end
       end
     end
   end

test/db/version_6.rb

@@ -14,4 +14,6 @@
     t.column :associated_id, :integer
     t.column :associated_type, :string
   end
+
+  add_index :audits, [:auditable_type, :auditable_id], name: 'auditable_index'
 end

test/upgrade_generator_test.rb

@@ -79,6 +79,16 @@ class UpgradeGeneratorTest < Rails::Generators::TestCase
     end
   end
 
+  test "should add 'version' to auditable_index" do
+    load_schema 6
+
+    run_generator %w(upgrade)
+
+    assert_migration "db/migrate/add_version_to_auditable_index.rb" do |content|
+      assert_match(/add_index :audits, \[:auditable_type, :auditable_id, :version\]/, content)
+    end
+  end
+
   test "generate migration with correct AR migration parent" do
     load_schema 1