1 files changed, 8 insertions, 25 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 01a9fd8763..863d8d3b8f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -31,8 +31,6 @@ module ActiveRecord
         def extract_default
           if blob_or_text_column?
             @default = null || strict ? nil : ''
-          elsif missing_default_forged_as_empty_string?(default)
-            @default = nil
           end
         end
 
@@ -59,17 +57,6 @@ module ActiveRecord
 
         private
 
-        # MySQL misreports NOT NULL column default when none is given.
-        # We can't detect this for columns which may have a legitimate ''
-        # default (string) but we can for others (integer, datetime, boolean,
-        # and the rest).
-        #
-        # Test whether the column has default '', is not null, and is not
-        # a type allowing default ''.
-        def missing_default_forged_as_empty_string?(default)
-          type != :string && !null && default == ''
-        end
-
         def assert_valid_default(default)
           if blob_or_text_column? && default.present?
             raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
@@ -106,12 +93,11 @@ module ActiveRecord
 
       ##
       # :singleton-method:
-      # By default, the MysqlAdapter will consider all columns of type <tt>tinyint(1)</tt>
-      # as boolean. If you wish to disable this emulation (which was the default
-      # behavior in versions 0.13.1 and earlier) you can add the following line
+      # By default, the Mysql2Adapter will consider all columns of type <tt>tinyint(1)</tt>
+      # as boolean. If you wish to disable this emulation you can add the following line
       # to your application.rb file:
       #
-      #   ActiveRecord::ConnectionAdapters::Mysql[2]Adapter.emulate_booleans = false
+      #   ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = false
       class_attribute :emulate_booleans
       self.emulate_booleans = true
 
@@ -400,10 +386,10 @@ module ActiveRecord
         log(sql, name) { @connection.query(sql) }
       end
 
-      # MysqlAdapter has to free a result after using it, so we use this method to write
-      # stuff in an abstract way without concerning ourselves about whether it needs to be
-      # explicitly freed or not.
-      def execute_and_free(sql, name = nil) #:nodoc:
+      # Mysql2Adapter doesn't have to free a result after using it, but we use this method
+      # to write stuff in an abstract way without concerning ourselves about whether it
+      # needs to be explicitly freed or not.
+      def execute_and_free(sql, name = nil) # :nodoc:
         yield execute(sql, name)
       end
 
@@ -432,7 +418,7 @@ module ActiveRecord
       # In the simple case, MySQL allows us to place JOINs directly into the UPDATE
       # query. However, this does not allow for LIMIT, OFFSET and ORDER. To support
       # these, we must use a subquery.
-      def join_to_update(update, select) #:nodoc:
+      def join_to_update(update, select, key) # :nodoc:
         if select.limit || select.offset || select.orders.any?
           super
         else
@@ -1105,11 +1091,8 @@ module ActiveRecord
         end
       end
 
-      ActiveRecord::Type.register(:json, MysqlJson, adapter: :mysql)
       ActiveRecord::Type.register(:json, MysqlJson, adapter: :mysql2)
-      ActiveRecord::Type.register(:string, MysqlString, adapter: :mysql)
       ActiveRecord::Type.register(:string, MysqlString, adapter: :mysql2)
-      ActiveRecord::Type.register(:unsigned_integer, Type::UnsignedInteger, adapter: :mysql)
       ActiveRecord::Type.register(:unsigned_integer, Type::UnsignedInteger, adapter: :mysql2)
     end
   end