Initialize `column.table_name` immediately for `column.serial?` correctly working

Currently the results of `column.serial?` is not correct. For
`column.serial?` correctly working, initialize `column.table_name`
immediately.

1 files changed, 16 insertions, 9 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 50f461b746..4bb2672bab 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -421,15 +421,16 @@ module ActiveRecord
 
       # Returns an array of +Column+ objects for the table specified by +table_name+.
       def columns(table_name) # :nodoc:
-        sql = "SHOW FULL FIELDS FROM #{quote_table_name(table_name)}"
-        execute_and_free(sql, 'SCHEMA') do |result|
-          each_hash(result).map do |field|
-            type_metadata = fetch_type_metadata(field[:Type], field[:Extra])
-            if type_metadata.type == :datetime && field[:Default] == "CURRENT_TIMESTAMP"
-              new_column(field[:Field], nil, type_metadata, field[:Null] == "YES", field[:Default], field[:Collation])
-            else
-              new_column(field[:Field], field[:Default], type_metadata, field[:Null] == "YES", nil, field[:Collation])
-            end
+        table_name = table_name.to_s
+        column_definitions(table_name).map do |field|
+          type_metadata = fetch_type_metadata(field[:Type], field[:Extra])
+          if type_metadata.type == :datetime && field[:Default] == "CURRENT_TIMESTAMP"
+            default, default_function = nil, field[:Default]
+          else
+            default, default_function = field[:Default], nil
+          end
+          new_column(field[:Field], default, type_metadata, field[:Null] == "YES", default_function, field[:Collation]).tap do |column|
+            column.instance_variable_set(:@table_name, table_name)
           end
         end
       end
@@ -874,6 +875,12 @@ module ActiveRecord
         @connection.query  "SET #{encoding} #{variable_assignments}"
       end
 
+      def column_definitions(table_name) # :nodoc:
+        execute_and_free("SHOW FULL FIELDS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
+          each_hash(result)
+        end
+      end
+
       def extract_foreign_key_action(structure, name, action) # :nodoc:
         if structure =~ /CONSTRAINT #{quote_column_name(name)} FOREIGN KEY .* REFERENCES .* ON #{action} (CASCADE|SET NULL|RESTRICT)/
           case $1