Don't modify the columns hash to set defaults from the attributes API

Nothing is directly using the columns for the default values anymore.
This step helps us get closer not not mutating the columns hash.

2 files changed, 25 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/attributes.rb b/activerecord/lib/active_record/attributes.rb
index 890a1314d9..3288108a6a 100644
--- a/activerecord/lib/active_record/attributes.rb
+++ b/activerecord/lib/active_record/attributes.rb
@@ -6,7 +6,9 @@ module ActiveRecord
 
     included do
       class_attribute :user_provided_columns, instance_accessor: false # :internal:
+      class_attribute :user_provided_defaults, instance_accessor: false # :internal:
       self.user_provided_columns = {}
+      self.user_provided_defaults = {}
     end
 
     module ClassMethods # :nodoc:
@@ -77,7 +79,11 @@ module ActiveRecord
         name = name.to_s
         clear_caches_calculated_from_columns
         # Assign a new hash to ensure that subclasses do not share a hash
-        self.user_provided_columns = user_provided_columns.merge(name => connection.new_column(name, options[:default], cast_type))
+        self.user_provided_columns = user_provided_columns.merge(name => cast_type)
+
+        if options.key?(:default)
+          self.user_provided_defaults = user_provided_defaults.merge(name => options[:default])
+        end
       end
 
       # Returns an array of column objects for the table associated with this class.
@@ -99,11 +105,18 @@ module ActiveRecord
 
       def add_user_provided_columns(schema_columns)
         existing_columns = schema_columns.map do |column|
-          user_provided_columns[column.name] || column
+          new_type = user_provided_columns[column.name]
+          if new_type
+            column.with_type(new_type)
+          else
+            column
+          end
         end
 
         existing_column_names = existing_columns.map(&:name)
-        new_columns = user_provided_columns.except(*existing_column_names).values
+        new_columns = user_provided_columns.except(*existing_column_names).map do |(name, type)|
+          connection.new_column(name, nil, type)
+        end
 
         existing_columns + new_columns
       end
@@ -117,6 +130,10 @@ module ActiveRecord
         @content_columns = nil
         @default_attributes = nil
       end
+
+      def raw_default_values
+        super.merge(user_provided_defaults)
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index 31ff08a89d..a444aac23c 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -252,7 +252,7 @@ module ActiveRecord
 
       def _default_attributes # :nodoc:
         @default_attributes ||= attributes_builder.build_from_database(
-          columns_hash.transform_values(&:default))
+          raw_default_values)
       end
 
       # Returns an array of column names as strings.
@@ -331,6 +331,10 @@ module ActiveRecord
           base.table_name
         end
       end
+
+      def raw_default_values
+        columns_hash.transform_values(&:default)
+      end
     end
   end
 end