incorrect_length_validation: Consider inclusion validations as an alternative

lib/active_record_doctor/detectors/incorrect_length_validation.rb

@@ -33,28 +33,44 @@ def message(model:, attribute:, table:, database_maximum:, model_maximum:)
       def detect
         each_model(except: config(:ignore_models), existing_tables_only: true) do |model|
           each_attribute(model, except: config(:ignore_attributes), type: [:string, :text]) do |column|
-            model_maximum = maximum_allowed_by_validations(model, column.name.to_sym)
-            next if model_maximum == column.limit
+            model_maximum = maximum_allowed_by_length_validation(model, column.name.to_sym)
+            database_maximum = column.limit
+            next if model_maximum == database_maximum
+            next if database_maximum && covered_by_inclusion_validation?(model, column.name.to_sym, database_maximum)
 
             problem!(
               model: model.name,
               attribute: column.name,
               table: model.table_name,
-              database_maximum: column.limit,
+              database_maximum: database_maximum,
               model_maximum: model_maximum
             )
           end
         end
       end
 
-      def maximum_allowed_by_validations(model, column)
+      def maximum_allowed_by_length_validation(model, column)
         length_validator = model.validators.find do |validator|
           validator.kind == :length &&
             validator.options.include?(:maximum) &&
             validator.attributes.include?(column)
         end
         length_validator ? length_validator.options[:maximum] : nil
       end
+
+      def covered_by_inclusion_validation?(model, column, limit)
+        inclusion_validator = model.validators.find do |validator|
+          validator.kind == :inclusion &&
+            validator.attributes.include?(column) &&
+            [:if, :unless].none? { |option| validator.options.key?(option) } &&
+            [:allow_nil, :allow_blank].none? { |option| validator.options[option] == true }
+        end
+
+        return false if !inclusion_validator
+
+        values = inclusion_validator.options[:in] || inclusion_validator.options[:within]
+        values.is_a?(Array) && values.all? { |value| value.is_a?(String) && value.size <= limit }
+      end
     end
   end
 end

test/active_record_doctor/detectors/incorrect_length_validation_test.rb

@@ -61,6 +61,74 @@ def test_no_validation_and_no_limit_is_ok
     refute_problems
   end
 
+  def test_array_inclusion_validation_with_shorter_values_and_limit_is_ok
+    Context.create_table(:users) do |t|
+      t.string :status, limit: 64
+    end.define_model do
+      validates :status, inclusion: { in: ["new", "vip", "a" * 64] }
+    end
+
+    refute_problems
+  end
+
+  def test_array_inclusion_validation_with_longer_values_and_limit_is_error
+    Context.create_table(:users) do |t|
+      t.string :status, limit: 64
+    end.define_model do
+      validates :status, inclusion: { in: ["new", "vip", "a" * 65] }
+    end
+
+    assert_problems(<<~OUTPUT)
+      the schema limits users.status to 64 characters but there's no length validator on Context::User.status - remove the database limit or add the validator
+    OUTPUT
+  end
+
+  def test_proc_inclusion_validation_and_limit_is_error
+    Context.create_table(:users) do |t|
+      t.string :status, limit: 64
+    end.define_model do
+      validates :status, inclusion: { in: ->(user) {} }
+    end
+
+    assert_problems(<<~OUTPUT)
+      the schema limits users.status to 64 characters but there's no length validator on Context::User.status - remove the database limit or add the validator
+    OUTPUT
+  end
+
+  def test_array_inclusion_validation_with_shorter_values_and_if_is_error
+    Context.create_table(:users) do |t|
+      t.string :status, limit: 64
+    end.define_model do
+      validates :status, inclusion: { in: ["new", "vip"] }, if: :condition?
+    end
+
+    assert_problems(<<~OUTPUT)
+      the schema limits users.status to 64 characters but there's no length validator on Context::User.status - remove the database limit or add the validator
+    OUTPUT
+  end
+
+  def test_array_inclusion_validation_with_shorter_values_and_allow_nil_is_error
+    Context.create_table(:users) do |t|
+      t.string :status, limit: 64
+    end.define_model do
+      validates :status, inclusion: { in: ["new", "vip"] }, allow_nil: true
+    end
+
+    assert_problems(<<~OUTPUT)
+      the schema limits users.status to 64 characters but there's no length validator on Context::User.status - remove the database limit or add the validator
+    OUTPUT
+  end
+
+  def test_array_inclusion_validation_with_shorter_values_and_disallow_nil_is_ok
+    Context.create_table(:users) do |t|
+      t.string :status, limit: 64
+    end.define_model do
+      validates :status, inclusion: { in: ["new", "vip"] }, allow_nil: false
+    end
+
+    refute_problems
+  end
+
   def test_config_ignore_models
     Context.create_table(:users) do |t|
       t.string :email, limit: 64