Remove `case macro` from `calculate_constructable`

Rails has abstract Reflection classes (`MacroReflection`,
`AssociationReflection` etc.) and concrete Reflection classes
(e.g. `HasManyReflection`, `HasOneReflection` etc.).
In many case `calculate_constructable` returns `true`, so
change `calculate_constructable` to always return `true` and
override this method if necessary.

1 files changed, 13 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index cbb5b99a05..823ca1f54f 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -501,14 +501,7 @@ module ActiveRecord
       private
 
         def calculate_constructable(macro, options)
-          case macro
-          when :belongs_to
-            !polymorphic?
-          when :has_one
-            !options[:through]
-          else
-            true
-          end
+          true
         end
 
         # Attempts to find the inverse association name automatically.
@@ -634,6 +627,12 @@ module ActiveRecord
           Associations::HasOneAssociation
         end
       end
+
+      private
+
+        def calculate_constructable(macro, options)
+          !options[:through]
+        end
     end
 
     class BelongsToReflection < AssociationReflection # :nodoc:
@@ -661,6 +660,12 @@ module ActiveRecord
       def join_id_for(owner) # :nodoc:
         owner[foreign_key]
       end
+
+      private
+
+        def calculate_constructable(macro, options)
+          !polymorphic?
+        end
     end
 
     class HasAndBelongsToManyReflection < AssociationReflection # :nodoc: