decide per index to reconcile class name field

Presently we only remove the class name field
if there's no index with inheritance at all
among the ones defined. This commit reconciles
all possible indices, skipping only the ones
where this field is needed.

lib/thinking_sphinx/configuration/minimum_fields.rb

@@ -6,8 +6,6 @@ def initialize(indices)
   end
 
   def reconcile
-    return unless no_inheritance_columns?
-
     field_collections.each do |collection|
       collection.fields.delete_if do |field|
         field.name == 'sphinx_internal_class_name'
@@ -20,18 +18,19 @@ def reconcile
   attr_reader :indices
 
   def field_collections
-    indices_of_type('plain').collect(&:sources).flatten +
+    plain_indices_without_inheritance.collect(&:sources).flatten +
     indices_of_type('rt')
   end
 
   def indices_of_type(type)
     indices.select { |index| index.type == type }
   end
 
-  def no_inheritance_columns?
-    indices.select { |index|
-      index.model.table_exists? &&
-      index.model.column_names.include?(index.model.inheritance_column)
-    }.empty?
+  def inheritance_columns?(index)
+    index.model.table_exists? && index.model.column_names.include?(index.model.inheritance_column)
+  end
+
+  def plain_indices_without_inheritance
+    indices_of_type('plain').reject(&method(:inheritance_columns?))
   end
 end

spec/thinking_sphinx/configuration/minimum_fields_spec.rb

@@ -38,13 +38,13 @@
     expect(index_b.fields).to eq([field_b2])
   end
 
-  it 'keeps the class name fields when one index model has a type column' do
+  it 'removes the class name fields only for the indices without type column' do
     allow(model_a).to receive(:column_names).and_return(['id', 'name', 'type'])
     allow(model_b).to receive(:column_names).and_return(['id', 'name'])
 
     subject.reconcile
 
     expect(index_a.sources.first.fields).to eq([field_a1, field_a2])
-    expect(index_b.fields).to eq([field_b1, field_b2])
+    expect(index_b.fields).to eq([field_b2])
   end
 end