Do not attempt to automatically find the inverse of a polymorphic `belongs_to` association

We can't automatically find the inverse of a polymorphic `belongs_to`
association without context.

[Ryuta Kamizono & Eric K Idema]

1 files changed, 4 insertions, 10 deletions

diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 101ac2d33a..8950be1ab7 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -611,13 +611,7 @@ module ActiveRecord
           if can_find_inverse_of_automatically?(self)
             inverse_name = ActiveSupport::Inflector.underscore(options[:as] || active_record.name.demodulize).to_sym
 
-            begin
-              reflection = klass._reflect_on_association(inverse_name)
-            rescue ArgumentError
-              # Give up: we couldn't compute the klass type so we won't be able
-              # to find any associations either.
-              reflection = false
-            end
+            reflection = klass._reflect_on_association(inverse_name)
 
             if valid_inverse_reflection?(reflection)
               return inverse_name
@@ -629,9 +623,6 @@ module ActiveRecord
         # +automatic_inverse_of+ method is a valid reflection. We must
         # make sure that the reflection's active_record name matches up
         # with the current reflection's klass name.
-        #
-        # Note: klass will always be valid because when there's a NameError
-        # from calling +klass+, +reflection+ will already be set to false.
         def valid_inverse_reflection?(reflection)
           reflection &&
             klass <= reflection.active_record &&
@@ -735,6 +726,9 @@ module ActiveRecord
       end
 
       private
+        def can_find_inverse_of_automatically?(_)
+          !polymorphic? && super
+        end
 
         def calculate_constructable(macro, options)
           !polymorphic?