missing_presence_validation: ignore counter cache columns

lib/active_record_doctor/detectors/missing_presence_validation.rb

@@ -30,6 +30,7 @@ def detect
           each_attribute(model, except: config(:ignore_attributes)) do |column|
             next unless validator_needed?(model, column)
             next if validator_present?(model, column)
+            next if counter_cache_column?(model, column)
 
             problem!(column: column.name, model: model.name)
           end
@@ -94,6 +95,12 @@ def presence_validator_present?(model, column)
       def inclusion_validator_items(validator)
         validator.options[:in] || validator.options[:within] || []
       end
+
+      def counter_cache_column?(model, column)
+        model.reflect_on_all_associations(:has_many).any? do |reflection|
+          reflection.has_cached_counter? && reflection.counter_cache_column == column.name
+        end
+      end
     end
   end
 end

test/active_record_doctor/detectors/missing_presence_validation_test.rb

@@ -139,6 +139,38 @@ def test_timestamps_are_not_reported
     refute_problems
   end
 
+  def test_counter_caches_are_not_reported
+    Context.create_table(:companies) do |t|
+      t.integer :users_count, default: 0, null: false
+    end.define_model do
+      has_many :users
+    end
+
+    Context.create_table(:users) do |t|
+      t.integer :company_id
+    end.define_model do
+      belongs_to :company, counter_cache: true
+    end
+
+    refute_problems
+  end
+
+  def test_counter_caches_with_custom_names_are_not_reported
+    Context.create_table(:companies) do |t|
+      t.integer :custom_users_count, default: 0, null: false
+    end.define_model do
+      has_many :users, counter_cache: :custom_users_count
+    end
+
+    Context.create_table(:users) do |t|
+      t.integer :company_id
+    end.define_model do
+      belongs_to :company, counter_cache: :custom_users_count
+    end
+
+    refute_problems
+  end
+
   def test_models_with_non_existent_tables_are_skipped
     Context.define_model(:User)