Revert "Merge pull request #19500 from ccutrer/dry_sti_subclass_finding"

This reverts commit 5cfa6a8ab997089c3012a82052c8c317b2e095f5, reversing
changes made to bfd5bf8313e6ea0bb2eccb68ee5076bb63f0b2db.

Reason: This broken travis build.

1 files changed, 19 insertions, 19 deletions

diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index d3ef88288c..24098f72dc 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -55,7 +55,7 @@ module ActiveRecord
           subclass = subclass_from_attributes(attrs)
         end
 
-        if subclass && subclass != self
+        if subclass
           subclass.new(*args, &block)
         else
           super
@@ -167,23 +167,17 @@ module ActiveRecord
       end
 
       def find_sti_class(type_name)
-        subclass = begin
-          if store_full_sti_class
-            ActiveSupport::Dependencies.constantize(type_name)
-          else
-            compute_type(type_name)
-          end
-        rescue NameError
-          raise SubclassNotFound,
-            "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " +
-            "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
-            "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
-            "or overwrite #{name}.inheritance_column to use another column for that information."
-        end
-        unless subclass == self || descendants.include?(subclass)
-          raise SubclassNotFound, "Invalid single-table inheritance type: #{type_name} is not a subclass of #{name}"
+        if store_full_sti_class
+          ActiveSupport::Dependencies.constantize(type_name)
+        else
+          compute_type(type_name)
         end
-        subclass
+      rescue NameError
+        raise SubclassNotFound,
+          "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " +
+          "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
+          "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
+          "or overwrite #{name}.inheritance_column to use another column for that information."
       end
 
       def type_condition(table = arel_table)
@@ -204,8 +198,14 @@ module ActiveRecord
       def subclass_from_attributes(attrs)
         subclass_name = attrs.with_indifferent_access[inheritance_column]
 
-        if subclass_name.present?
-          find_sti_class(subclass_name)
+        if subclass_name.present? && subclass_name != self.name
+          subclass = subclass_name.safe_constantize
+
+          unless descendants.include?(subclass)
+            raise ActiveRecord::SubclassNotFound.new("Invalid single-table inheritance type: #{subclass_name} is not a subclass of #{name}")
+          end
+
+          subclass
         end
       end
     end