Merge pull request #5347 from rafaelfranca/fix-has_many_association-3-2

[3-2-stable] Fix has many through associations when mass_assignment_sanitizer is :strict

1 files changed, 7 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
index f95e5337c2..fd0e90aaf0 100644
--- a/activerecord/lib/active_record/associations/through_association.rb
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -37,9 +37,7 @@ module ActiveRecord
         # situation it is more natural for the user to just create or modify their join records
         # directly as required.
         def construct_join_attributes(*records)
-          if source_reflection.macro != :belongs_to
-            raise HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(owner, reflection)
-          end
+          ensure_mutable
 
           join_attributes = {
             source_reflection.foreign_key =>
@@ -73,6 +71,12 @@ module ActiveRecord
           !owner[through_reflection.foreign_key].nil?
         end
 
+        def ensure_mutable
+          if source_reflection.macro != :belongs_to
+            raise HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(owner, reflection)
+          end
+        end
+
         def ensure_not_nested
           if reflection.nested?
             raise HasManyThroughNestedAssociationsAreReadonly.new(owner, reflection)