Move extract_scale to decimal type

The only type that has a scale is decimal. There's a special case where
decimal columns with 0 scale are type cast to integers if the scale is
not specified. Appears to only affect schema dumping.

3 files changed, 5 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/type.rb b/activerecord/lib/active_record/connection_adapters/type.rb
index 763176cb2b..9103ae85c0 100644
--- a/activerecord/lib/active_record/connection_adapters/type.rb
+++ b/activerecord/lib/active_record/connection_adapters/type.rb
@@ -22,8 +22,8 @@ module ActiveRecord
       class << self
         def extract_scale(sql_type)
           case sql_type
-            when /^(numeric|decimal|number)\((\d+)\)/i then 0
-            when /^(numeric|decimal|number)\((\d+)(,(\d+))\)/i then $4.to_i
+            when /\((\d+)\)/ then 0
+            when /\((\d+)(,(\d+))\)/ then $3.to_i
           end
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/type/decimal.rb b/activerecord/lib/active_record/connection_adapters/type/decimal.rb
index ac5af4b963..a8cd1cf5b5 100644
--- a/activerecord/lib/active_record/connection_adapters/type/decimal.rb
+++ b/activerecord/lib/active_record/connection_adapters/type/decimal.rb
@@ -4,6 +4,8 @@ module ActiveRecord
       class Decimal < Value # :nodoc:
         include Numeric
 
+        delegate :extract_scale, to: Type
+
         def type
           :decimal
         end
diff --git a/activerecord/lib/active_record/connection_adapters/type/value.rb b/activerecord/lib/active_record/connection_adapters/type/value.rb
index 289c27f6d4..52d9ed9bc0 100644
--- a/activerecord/lib/active_record/connection_adapters/type/value.rb
+++ b/activerecord/lib/active_record/connection_adapters/type/value.rb
@@ -3,10 +3,7 @@ module ActiveRecord
     module Type
       class Value # :nodoc:
         def type; end
-
-        def extract_scale(sql_type)
-          Type.extract_scale(sql_type)
-        end
+        def extract_scale(sql_type); end
 
         def type_cast(value)
           cast_value(value) unless value.nil?