1 files changed, 22 insertions, 21 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 4333cd1f57..003ba6eff5 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -384,11 +384,11 @@ module ActiveRecord
               mysql_index_type = row[:Index_type].downcase.to_sym
               index_type  = INDEX_TYPES.include?(mysql_index_type)  ? mysql_index_type : nil
               index_using = INDEX_USINGS.include?(mysql_index_type) ? mysql_index_type : nil
-              indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], [], nil, nil, index_type, index_using, row[:Index_comment].presence)
+              indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], {}, nil, nil, index_type, index_using, row[:Index_comment].presence)
             end
 
             indexes.last.columns << row[:Column_name]
-            indexes.last.lengths << row[:Sub_part]
+            indexes.last.lengths.merge!(row[:Column_name] => row[:Sub_part]) if row[:Sub_part]
           end
         end
 
@@ -509,7 +509,7 @@ module ActiveRecord
       end
 
       def add_sql_comment!(sql, comment) # :nodoc:
-        sql << " COMMENT #{quote(comment)}" if comment
+        sql << " COMMENT #{quote(comment)}" if comment.present?
         sql
       end
 
@@ -570,22 +570,23 @@ module ActiveRecord
 
       # Maps logical Rails types to MySQL-specific data types.
       def type_to_sql(type, limit = nil, precision = nil, scale = nil, unsigned = nil)
-        sql = case type.to_s
-              when "integer"
-                integer_to_sql(limit)
-              when "text"
-                text_to_sql(limit)
-              when "blob"
-                binary_to_sql(limit)
-              when "binary"
-                if (0..0xfff) === limit
-                  "varbinary(#{limit})"
-                else
-                  binary_to_sql(limit)
-                end
-        else
-                super(type, limit, precision, scale)
-        end
+        sql = \
+          case type.to_s
+          when "integer"
+            integer_to_sql(limit)
+          when "text"
+            text_to_sql(limit)
+          when "blob"
+            binary_to_sql(limit)
+          when "binary"
+            if (0..0xfff) === limit
+              "varbinary(#{limit})"
+            else
+              binary_to_sql(limit)
+            end
+          else
+            super(type, limit, precision, scale)
+          end
 
         sql << " unsigned" if unsigned && type != :primary_key
         sql
@@ -817,8 +818,8 @@ module ActiveRecord
 
       private
 
-      # MySQL is too stupid to create a temporary table for use subquery, so we have
-      # to give it some prompting in the form of a subsubquery. Ugh!
+        # MySQL is too stupid to create a temporary table for use subquery, so we have
+        # to give it some prompting in the form of a subsubquery. Ugh!
         def subquery_for(key, select)
           subsubselect = select.clone
           subsubselect.projections = [key]