Merge pull request rails#47889 from aharpole/fix-foreign-key-infinite-recursion

fix infinite recursion with foreign_key

Author: matthewd

activerecord/lib/active_record/reflection.rb

@@ -493,12 +493,12 @@ def join_table
         @join_table ||= -(options[:join_table]&.to_s || derive_join_table)
       end
 
-      def foreign_key
+      def foreign_key(infer_from_inverse_of: true)
         @foreign_key ||= if options[:query_constraints]
           # composite foreign keys support
           options[:query_constraints].map { |fk| fk.to_s.freeze }.freeze
         else
-          -(options[:foreign_key]&.to_s || derive_foreign_key)
+          -(options[:foreign_key]&.to_s || derive_foreign_key(infer_from_inverse_of: infer_from_inverse_of))
         end
       end
 
@@ -726,13 +726,13 @@ def derive_class_name
           class_name.camelize
         end
 
-        def derive_foreign_key
+        def derive_foreign_key(infer_from_inverse_of: true)
           if belongs_to?
             "#{name}_id"
           elsif options[:as]
             "#{options[:as]}_id"
-          elsif options[:inverse_of]
-            inverse_of.foreign_key
+          elsif options[:inverse_of] && infer_from_inverse_of
+            inverse_of.foreign_key(infer_from_inverse_of: false)
           else
             active_record.model_name.to_s.foreign_key
           end

activerecord/test/cases/reflection_test.rb

@@ -3,6 +3,7 @@
 require "cases/helper"
 require "models/topic"
 require "models/customer"
+require "models/comment"
 require "models/company"
 require "models/company_in_module"
 require "models/ship"
@@ -461,6 +462,7 @@ def test_never_validate_association_if_explicit
   def test_foreign_key
     assert_equal "author_id", Author.reflect_on_association(:posts).foreign_key.to_s
     assert_equal "category_id", Post.reflect_on_association(:categorizations).foreign_key.to_s
+    assert_equal "comment_id", FirstPost.reflect_on_association(:comment_with_inverse).foreign_key.to_s
   end
 
   def test_foreign_key_is_inferred_from_model_name

activerecord/test/models/comment.rb

@@ -23,6 +23,8 @@ class Comment < ActiveRecord::Base
   belongs_to :first_post, foreign_key: :post_id
   belongs_to :special_post_with_default_scope, foreign_key: :post_id
 
+  has_one :post_with_inverse, ->(comment) { where(id: comment.post_id) }, class_name: "FirstPost", inverse_of: :comment_with_inverse
+
   has_many :children, class_name: "Comment", inverse_of: :parent
   belongs_to :parent, class_name: "Comment", counter_cache: :children_count, inverse_of: :children
 

activerecord/test/models/post.rb

@@ -234,6 +234,7 @@ class FirstPost < ActiveRecord::Base
 
   has_many :comments, foreign_key: :post_id
   has_one  :comment,  foreign_key: :post_id
+  has_one  :comment_with_inverse, class_name: "Comment", inverse_of: :post_with_inverse
 end
 
 class PostWithDefaultSelect < ActiveRecord::Base