Correctly dump `:options` on `create_table` for MySQL

3 files changed, 18 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index c4a37f8538..654ed0250e 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -14,6 +14,10 @@ module ActiveRecord
         {}
       end
 
+      def table_options(table_name)
+        nil
+      end
+
       # Truncates a table alias according to the limits of the current adapter.
       def table_alias_for(table_name)
         table_name[0...table_alias_length].tr('.', '_')
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 76aee452ca..75c81cadfa 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -686,6 +686,16 @@ module ActiveRecord
         end
       end
 
+      def table_options(table_name)
+        create_table_info = select_one("SHOW CREATE TABLE #{quote_table_name(table_name)}")["Create Table"]
+
+        # strip create_definitions and partition_options
+        raw_table_options = create_table_info.sub(/\A.*\n\) /m, '').sub(/\n\/\*!.*\*\/\n\z/m, '').strip
+
+        # strip AUTO_INCREMENT
+        raw_table_options.sub(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')
+      end
+
       # Maps logical Rails types to MySQL-specific data types.
       def type_to_sql(type, limit = nil, precision = nil, scale = nil)
         case type.to_s
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index eaeaf0321b..321611d6c9 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -131,6 +131,10 @@ HEADER
             tbl.print ", id: false"
           end
           tbl.print ", force: :cascade"
+
+          table_options = @connection.table_options(table)
+          tbl.print ", options: #{table_options.inspect}" unless table_options.blank?
+
           tbl.puts " do |t|"
 
           # then dump all non-primary key columns