Remove special case in schema dumper for decimal without scale

activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb

@@ -20,15 +20,8 @@ module ActiveRecord
       def prepare_column_options(column, types)
         spec = {}
         spec[:name]      = column.name.inspect
-
-        # AR has an optimization which handles zero-scale decimals as integers. This
-        # code ensures that the dumper still dumps the column as a decimal.
-        spec[:type]      = if column.type == :integer && /^(numeric|decimal)/ =~ column.sql_type
-                             'decimal'
-                           else
-                             column.type.to_s
-                           end
-        spec[:limit]     = column.limit.inspect if column.limit != types[column.type][:limit] && spec[:type] != 'decimal'
+        spec[:type]      = column.type.to_s
+        spec[:limit]     = column.limit.inspect if column.limit != types[column.type][:limit]
         spec[:precision] = column.precision.inspect if column.precision
         spec[:scale]     = column.scale.inspect if column.scale
         spec[:null]      = 'false' unless column.null

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -396,7 +396,7 @@ module ActiveRecord
           precision = extract_precision(sql_type)
 
           if scale == 0
-            Type::Integer.new(precision: precision)
+            Type::DecimalWithoutScale.new(precision: precision)
           else
             Type::Decimal.new(precision: precision, scale: scale)
           end

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -543,7 +543,7 @@ module ActiveRecord
             load_additional_types(type_map, [oid])
           end
 
-          type_map.fetch(normalize_oid_type(oid, fmod), sql_type) {
+          type_map.fetch(oid, fmod, sql_type) {
             warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
             Type::Value.new.tap do |cast_type|
               type_map.register_type(oid, cast_type)
@@ -551,23 +551,6 @@ module ActiveRecord
           }
         end
 
-        OID_FOR_DECIMAL_TREATED_AS_INT = 23 # :nodoc:
-
-        def normalize_oid_type(ftype, fmod)
-          # The type for the numeric depends on the width of the field,
-          # so we'll do something special here.
-          #
-          # When dealing with decimal columns:
-          #
-          # places after decimal  = fmod - 4 & 0xffff
-          # places before decimal = (fmod - 4) >> 16 & 0xffff
-          if ftype == 1700 && (fmod - 4 & 0xffff).zero?
-            OID_FOR_DECIMAL_TREATED_AS_INT
-          else
-            ftype
-          end
-        end
-
         def initialize_type_map(m)
           register_class_with_limit m, 'int2', OID::Integer
           m.alias_type 'int4', 'int2'
@@ -610,20 +593,27 @@ module ActiveRecord
           m.alias_type 'lseg', 'varchar'
           m.alias_type 'box', 'varchar'
 
-          m.register_type 'timestamp' do |_, sql_type|
+          m.register_type 'timestamp' do |_, _, sql_type|
             precision = extract_precision(sql_type)
             OID::DateTime.new(precision: precision)
           end
 
-          m.register_type 'numeric' do |_, sql_type|
+          m.register_type 'numeric' do |_, fmod, sql_type|
             precision = extract_precision(sql_type)
             scale = extract_scale(sql_type)
-            OID::Decimal.new(precision: precision, scale: scale)
-          end
 
-          m.register_type OID_FOR_DECIMAL_TREATED_AS_INT do |_, sql_type|
-            precision = extract_precision(sql_type)
-            OID::Integer.new(precision: precision)
+            # The type for the numeric depends on the width of the field,
+            # so we'll do something special here.
+            #
+            # When dealing with decimal columns:
+            #
+            # places after decimal  = fmod - 4 & 0xffff
+            # places before decimal = (fmod - 4) >> 16 & 0xffff
+            if fmod && (fmod - 4 & 0xffff).zero?
+              Type::DecimalWithoutScale.new(precision: precision)
+            else
+              OID::Decimal.new(precision: precision, scale: scale)
+            end
           end
 
           load_additional_types(m)

activerecord/lib/active_record/connection_adapters/type.rb

@@ -7,6 +7,7 @@ require 'active_record/connection_adapters/type/boolean'
 require 'active_record/connection_adapters/type/date'
 require 'active_record/connection_adapters/type/date_time'
 require 'active_record/connection_adapters/type/decimal'
+require 'active_record/connection_adapters/type/decimal_without_scale'
 require 'active_record/connection_adapters/type/float'
 require 'active_record/connection_adapters/type/integer'
 require 'active_record/connection_adapters/type/string'

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

@@ -0,0 +1,13 @@
+require 'active_record/connection_adapters/type/integer'
+
+module ActiveRecord
+  module ConnectionAdapters
+    module Type
+      class DecimalWithoutScale < Integer # :nodoc:
+        def type
+          :decimal
+        end
+      end
+    end
+  end
+end

activerecord/test/cases/connection_adapters/type_lookup_test.rb

@@ -77,12 +77,16 @@ module ActiveRecord
         assert_lookup_type :integer, 'tinyint'
         assert_lookup_type :integer, 'smallint'
         assert_lookup_type :integer, 'bigint'
-        assert_lookup_type :integer, 'decimal(2)'
-        assert_lookup_type :integer, 'decimal(2,0)'
-        assert_lookup_type :integer, 'numeric(2)'
-        assert_lookup_type :integer, 'numeric(2,0)'
-        assert_lookup_type :integer, 'number(2)'
-        assert_lookup_type :integer, 'number(2,0)'
+      end
+
+      def test_decimal_without_scale
+        types = %w{decimal(2) decimal(2,0) numeric(2) numeric(2,0) number(2) number(2,0)}
+        types.each do |type|
+          cast_type = @connection.type_map.lookup(type)
+
+          assert_equal :decimal, cast_type.type
+          assert_equal 2, cast_type.type_cast(2.1)
+        end
       end
 
       private