Merge pull request #15200 from sgrif/sg-type-map-mysql

Use the generic type map object for mysql field lookups

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -297,23 +297,17 @@ def cast_value(value)
           end
         end
 
-        TYPES = {}
+        class << self
+          TYPES = ConnectionAdapters::Type::HashLookupTypeMap.new # :nodoc:
 
-        # Register an MySQL +type_id+ with a typecasting object in
-        # +type+.
-        def self.register_type(type_id, type)
-          TYPES[type_id] = type
-        end
-
-        def self.alias_type(new, old)
-          TYPES[new] = TYPES[old]
-        end
+          delegate :register_type, :alias_type, to: :TYPES
 
-        def self.find_type(field)
+          def find_type(field)
             if field.type == Mysql::Field::TYPE_TINY && field.length > 1
-            TYPES[Mysql::Field::TYPE_LONG]
+              TYPES.lookup(Mysql::Field::TYPE_LONG)
             else
-            TYPES.fetch(field.type) { Type::Value.new }
+              TYPES.lookup(field.type)
+            end
           end
         end
 
@@ -322,18 +316,10 @@ def self.find_type(field)
         alias_type Mysql::Field::TYPE_LONGLONG,   Mysql::Field::TYPE_LONG
         alias_type Mysql::Field::TYPE_NEWDECIMAL, Mysql::Field::TYPE_LONG
 
-        register_type Mysql::Field::TYPE_VAR_STRING, Type::Value.new
-        register_type Mysql::Field::TYPE_BLOB, Type::Value.new
         register_type Mysql::Field::TYPE_DATE, Type::Date.new
         register_type Mysql::Field::TYPE_DATETIME, Fields::DateTime.new
         register_type Mysql::Field::TYPE_TIME, Fields::Time.new
         register_type Mysql::Field::TYPE_FLOAT, Type::Float.new
-
-        Mysql::Field.constants.grep(/TYPE/).map { |class_name|
-          Mysql::Field.const_get class_name
-        }.reject { |const| TYPES.key? const }.each do |const|
-          register_type const, Type::Value.new
-        end
       end
 
       def initialize_type_map(m) # :nodoc:

activerecord/lib/active_record/connection_adapters/type.rb

@@ -11,7 +11,9 @@
 require 'active_record/connection_adapters/type/string'
 require 'active_record/connection_adapters/type/text'
 require 'active_record/connection_adapters/type/time'
+
 require 'active_record/connection_adapters/type/type_map'
+require 'active_record/connection_adapters/type/hash_lookup_type_map'
 
 module ActiveRecord
   module ConnectionAdapters

activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb

+module ActiveRecord
+  module ConnectionAdapters
+    module Type
+      class HashLookupTypeMap < TypeMap # :nodoc:
+        def lookup(type)
+          @mapping.fetch(type, proc { default_value }).call(type)
+        end
+
+        def alias_type(type, alias_type)
+          register_type(type) { lookup(alias_type) }
+        end
+      end
+    end
+  end
+end

activerecord/test/cases/connection_adapters/type/type_map_test.rb

@@ -95,6 +95,19 @@ def test_requires_value_or_block
             mapping.register_type(/only key/i)
           end
         end
+
+        def test_lookup_non_strings
+          mapping = HashLookupTypeMap.new
+
+          mapping.register_type(1, 'string')
+          mapping.register_type(2, 'int')
+          mapping.alias_type(3, 1)
+
+          assert_equal mapping.lookup(1), 'string'
+          assert_equal mapping.lookup(2), 'int'
+          assert_equal mapping.lookup(3), 'string'
+          assert_kind_of Type::Value, mapping.lookup(4)
+        end
       end
     end
   end