Allowing for indexes on STI subclasses when parents are indexed as well.

features/sti_searching.feature

@@ -12,3 +12,8 @@ Feature: Searching via STI model relationships
     Given Sphinx is running
     And I am searching on cats
     Then I should get as many results as there are cats
+
+  Scenario: Searching across super and subclass indexes
+    Given Sphinx is running
+    When I search for "fantastic"
+    Then I should get 1 result

features/support/db/fixtures/foxes.rb

@@ -0,0 +1,3 @@
+%w( fantastic ).each do |name|
+  Fox.create :name => name
+end

features/support/models/fox.rb

@@ -0,0 +1,5 @@
+class Fox < Animal
+  define_index do
+    indexes :name
+  end
+end

lib/thinking_sphinx.rb

@@ -63,6 +63,13 @@ def self.version
   def self.indexed_models
     Thread.current[:thinking_sphinx_indexed_models] ||= []
   end
+
+  def self.superclass_indexed_models
+    klasses = indexed_models.collect { |name| name.constantize }
+    klasses.reject { |klass|
+      klass.superclass.ancestors.any? { |ancestor| klasses.include?(ancestor) }
+    }.collect { |klass| klass.name }
+  end
 
   def self.unique_id_expression(offset = nil)
     "* #{indexed_models.size} + #{offset || 0}"

lib/thinking_sphinx/active_record.rb

@@ -127,6 +127,7 @@ def define_index(name = nil, &block)
 
         unless ThinkingSphinx.indexed_models.include?(self.name)
           ThinkingSphinx.indexed_models << self.name
+          ThinkingSphinx.indexed_models.sort!
         end
 
         add_sphinx_callbacks_and_extend(index.delta?)
@@ -166,11 +167,11 @@ def delta_index_names
         sphinx_indexes.select(&:delta?).collect(&:delta_name)
       end
 
-      def to_riddle(offset)
+      def to_riddle
         sphinx_database_adapter.setup
 
         local_sphinx_indexes.collect { |index|
-          index.to_riddle(offset)
+          index.to_riddle(sphinx_offset)
         }.flatten
       end
 
@@ -195,6 +196,10 @@ def delete_in_index(index, document_id)
         )
       end
 
+      def sphinx_offset
+        ThinkingSphinx.superclass_indexed_models.index eldest_indexed_ancestor
+      end
+
       private
 
       def local_sphinx_indexes
@@ -219,6 +224,12 @@ def add_sphinx_callbacks_and_extend(delta = false)
           after_commit  :index_delta
         end
       end
+
+      def eldest_indexed_ancestor
+        ancestors.reverse.detect { |ancestor|
+          ThinkingSphinx.indexed_models.include?(ancestor.name)
+        }.name
+      end
     end
 
     def in_index?(suffix)
@@ -263,7 +274,7 @@ def primary_key_for_sphinx
 
     def sphinx_document_id
       primary_key_for_sphinx * ThinkingSphinx.indexed_models.size +
-        ThinkingSphinx.indexed_models.index(self.class.source_of_sphinx_index.name)
+        self.class.sphinx_offset
     end
 
     private

lib/thinking_sphinx/configuration.rb

@@ -147,8 +147,8 @@ def build(file_path=nil)
 
       @configuration.indexes.clear
 
-      ThinkingSphinx.indexed_models.each_with_index do |model, model_index|
-        @configuration.indexes.concat model.constantize.to_riddle(model_index)
+      ThinkingSphinx.indexed_models.each do |model|
+        @configuration.indexes.concat model.constantize.to_riddle
       end
 
       open(file_path, "w") do |file|

spec/thinking_sphinx/active_record_spec.rb

@@ -365,19 +365,9 @@
     it "should return values with the expected offset" do
       person      = Person.find(:first)
       model_count = ThinkingSphinx.indexed_models.length
-      offset      = ThinkingSphinx.indexed_models.index("Person")
+      Person.stub!(:sphinx_offset => 3)
 
-      (person.id * model_count + offset).should == person.sphinx_document_id
-
-      alpha       = Alpha.find(:first)
-      offset      = ThinkingSphinx.indexed_models.index("Alpha")
-
-      (alpha.id * model_count + offset).should == alpha.sphinx_document_id
-
-      beta        = Beta.find(:first)
-      offset      = ThinkingSphinx.indexed_models.index("Beta")
-
-      (beta.id * model_count + offset).should == beta.sphinx_document_id
+      (person.id * model_count + 3).should == person.sphinx_document_id
     end
   end
 
@@ -510,4 +500,25 @@
       Alpha.delta_index_names.should == ['foo_delta']
     end
   end
+
+  describe '.sphinx_offset' do
+    it "should return the index of the model's name in all known indexed models" do
+      ThinkingSphinx.stub!(:indexed_models => ['Alpha', 'Beta'])
+
+      Alpha.sphinx_offset.should == 0
+      Beta.sphinx_offset.should  == 1
+    end
+
+    it "should ignore classes that have indexed superclasses" do
+      ThinkingSphinx.stub!(:indexed_models => ['Alpha', 'Parent', 'Person'])
+
+      Person.sphinx_offset.should == 1
+    end
+
+    it "should respect first known indexed parents" do
+      ThinkingSphinx.stub!(:indexed_models => ['Alpha', 'Parent', 'Person'])
+
+      Parent.sphinx_offset.should == 1
+    end
+  end
 end

spec/thinking_sphinx_spec.rb

@@ -91,6 +91,20 @@
     end
   end
 
+  describe '.superclass_indexed_models' do
+    it "should return indexed model names" do
+      ThinkingSphinx.stub!(:indexed_models => ['Alpha', 'Beta'])
+
+      ThinkingSphinx.superclass_indexed_models.should == ['Alpha', 'Beta']
+    end
+
+    it "should not include classes which have indexed superclasses" do
+      ThinkingSphinx.stub!(:indexed_models => ['Parent', 'Person'])
+
+      ThinkingSphinx.superclass_indexed_models.should == ['Person']
+    end
+  end
+
   describe "use_group_by_shortcut? method" do
     before :each do
       adapter = defined?(JRUBY_VERSION) ? :JdbcAdapter : :MysqlAdapter