Merge pull request rails#52797 from fatkodima/fix-nested-attributes-for-cpk

Fix updating nested attributes for models with composite primary keys

Author: kamipo

activerecord/lib/active_record/nested_attributes.rb

@@ -524,12 +524,12 @@ def assign_nested_attributes_for_collection_association(association_name, attrib
             unless reject_new_record?(association_name, attributes)
               association.reader.build(attributes.except(*UNASSIGNABLE_KEYS))
             end
-          elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes["id"].to_s }
+          elsif existing_record = find_record_by_id(existing_records, attributes["id"])
             unless call_reject_if(association_name, attributes)
               # Make sure we are operating on the actual object which is in the association's
               # proxy_target array (either by finding it, or adding it if not found)
               # Take into account that the proxy_target may have changed due to callbacks
-              target_record = association.target.detect { |record| record.id.to_s == attributes["id"].to_s }
+              target_record = find_record_by_id(association.target, attributes["id"])
               if target_record
                 existing_record = target_record
               else
@@ -620,5 +620,16 @@ def raise_nested_attributes_record_not_found!(association_name, record_id)
         raise RecordNotFound.new("Couldn't find #{model} with ID=#{record_id} for #{self.class.name} with ID=#{id}",
                                  model, "id", record_id)
       end
+
+      def find_record_by_id(records, id)
+        return if records.empty?
+
+        if records.first.class.composite_primary_key?
+          id = Array(id).map(&:to_s)
+          records.find { |record| Array(record.id).map(&:to_s) == id }
+        else
+          records.find { |record| record.id.to_s == id.to_s }
+        end
+      end
   end
 end

activerecord/test/cases/nested_attributes_test.rb

@@ -14,6 +14,7 @@
 require "models/pet"
 require "models/entry"
 require "models/message"
+require "models/cpk"
 require "active_support/hash_with_indifferent_access"
 
 class TestNestedAttributesInGeneral < ActiveRecord::TestCase
@@ -232,6 +233,15 @@ def test_should_not_create_duplicates_with_create_with
       )
     end
   end
+
+  def test_updating_models_with_cpk_provided_as_strings
+    book = Cpk::Book.create!(id: [1, 2], shop_id: 3)
+    book.chapters.create!(id: [1, 3], title: "Title")
+
+    book.update!(chapters_attributes: { id: ["1", "3"], title: "New title" })
+    assert_equal 1, book.reload.chapters.count
+    assert_equal "New title", book.chapters.first.title
+  end
 end
 
 class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase

activerecord/test/models/cpk/book.rb

@@ -10,6 +10,7 @@ class Book < ActiveRecord::Base
     belongs_to :author, class_name: "Cpk::Author"
 
     has_many :chapters, foreign_key: [:author_id, :book_id]
+    accepts_nested_attributes_for :chapters
 
     before_destroy :prevent_destroy_if_set