Define only one version of a method

lib/active_data/model/representation.rb

@@ -1,3 +1,4 @@
+require 'active_model/version'
 require 'active_data/model/attributes/reflections/represents'
 require 'active_data/model/attributes/represents'
 
@@ -71,19 +72,21 @@ def emerge_represented_attributes_errors!
         end
       end
 
-      def move_errors(from, to)
-        if ActiveModel.gem_version < Gem::Version.new('6.1.0')
-          # Rails 5 pollutes messages with an empty array on key data fetch attempt
-          return unless errors.messages.key?(from) && errors.messages[from].present?
-
-          errors[to].concat(errors.messages[from])
-          errors.delete(from)
-        else
+      case ActiveModel.version.to_s
+      when /^6\.1\./, /^7\./
+        def move_errors(from, to)
           errors[from].each do |error_message|
             errors.add(to, error_message)
             errors.delete(from)
           end
         end
+      else # up to 6.0.x
+        def move_errors(from, to)
+          return unless errors.messages.key?(from) && errors.messages[from].present?
+
+          errors[to].concat(errors.messages[from])
+          errors.delete(from)
+        end
       end
     end
   end

lib/active_data/model/scopes.rb

@@ -37,29 +37,39 @@ def respond_to_missing?(method, _)
           super || self.class._scope_model.respond_to?(method)
         end
 
-        def method_missing(method, *args, **kwargs, &block)
-          with_scope do
-            model = self.class._scope_model
-            if model.respond_to?(method)
-              # ruby 2.6 does not understand kwargs?
-              # Fixed in 2.7 - https://rubyreferences.github.io/rubychanges/2.7.html#keyword-argument-related-changes
-              #
-              # > empty hash splat doesn’t pass empty hash as a positional argument.
-              result = if kwargs.empty?
-                         model.public_send(method, *args, &block)
-                       else
-                         model.public_send(method, *args, **kwargs, &block)
-                       end
-
-              # ruby 3.0 returns plain arrays when subclasses receive standard methods
-              # so we need to wrap again.
-              # https://rubyreferences.github.io/rubychanges/3.0.html#array-always-returning-array
-              #
-              # > On custom classes inherited from `Array`, some methods previously were returning an instance of
-              # > this class, and others returned `Array`. Now they all do the latter.
-              result.is_a?(ActiveData::Model::Scopes) ? result : model.scope_class.new(result)
-            else
-              super
+        case RAILS_VERSION
+        when /\A3\./
+          def method_missing(method, *args, **kwargs, &block)
+            with_scope do
+              model = self.class._scope_model
+              if model.respond_to?(method)
+                result = model.public_send(method, *args, **kwargs, &block)
+                result.is_a?(ActiveData::Model::Scopes) ? result : model.scope_class.new(result)
+              else
+                super
+              end
+            end
+          end
+        when /\A2\.7\./
+          def method_missing(method, *args, **kwargs, &block)
+            with_scope do
+              model = self.class._scope_model
+              if model.respond_to?(method)
+                model.public_send(method, *args, **kwargs, &block)
+              else
+                super
+              end
+            end
+          end
+        else # up to 2.6.x
+          def method_missing(method, *args, &block)
+            with_scope do
+              model = self.class._scope_model
+              if model.respond_to?(method)
+                model.public_send(method, *args, &block)
+              else
+                super
+              end
             end
           end
         end

lib/active_data/model/validations/nested.rb

@@ -1,3 +1,5 @@
+require 'active_model/version'
+
 module ActiveData
   module Model
     module Validations
@@ -12,20 +14,21 @@ def self.validate_nested(record, name, value)
           end
         end
 
-        def self.import_errors(from, to, prefix)
-          if ActiveModel.gem_version < Gem::Version.new('6.1.0')
-            # legacy ActiveModel iterates over key/message pairs
+        case ActiveModel.version.to_s
+        when /^6\.1\./, /^7\./
+          def self.import_errors(from, to, prefix)
+            from.each do |error|
+              key = "#{prefix}.#{error.attribute}"
+              to.import(error, attribute: key) unless to.added?(key, error.type, error.options)
+            end
+          end
+        else # up to 6.0.x
+          def self.import_errors(from, to, prefix)
             from.each do |key, message|
               key = "#{prefix}.#{key}"
               to[key] << message
               to[key].uniq!
             end
-          else
-            # newer ActiveModel iterates over ActiveMode::Error instances
-            from.each do |error|
-              key = "#{prefix}.#{error.attribute}"
-              to.import(error, attribute: key) unless to.added?(key, error.type, error.options)
-            end
           end
         end