Merge pull request rails#47836 from Shopify/pm/cpk-relation-handler

Only default to select primary key when non-composite

Author: eileencodes

activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb

@@ -9,7 +9,11 @@ def call(attribute, value)
         end
 
         if value.select_values.empty?
-          value = value.select(value.table[value.klass.primary_key])
+          if value.klass.composite_primary_key?
+            raise ArgumentError, "Cannot map composite primary key #{value.klass.primary_key} to #{attribute.name}"
+          else
+            value = value.select(value.table[value.klass.primary_key])
+          end
         end
 
         attribute.in(value.arel)

activerecord/test/cases/relations_test.rb

@@ -27,9 +27,10 @@
 require "models/categorization"
 require "models/edge"
 require "models/subscriber"
+require "models/cpk"
 
 class RelationTest < ActiveRecord::TestCase
-  fixtures :authors, :author_addresses, :topics, :entrants, :developers, :people, :companies, :developers_projects, :accounts, :categories, :categorizations, :categories_posts, :posts, :comments, :tags, :taggings, :cars, :minivans
+  fixtures :authors, :author_addresses, :topics, :entrants, :developers, :people, :companies, :developers_projects, :accounts, :categories, :categorizations, :categories_posts, :posts, :comments, :tags, :taggings, :cars, :minivans, :cpk_orders
 
   def test_do_not_double_quote_string_id
     van = Minivan.last
@@ -945,6 +946,21 @@ def test_find_all_using_where_with_relation_and_alternate_primary_key
     }
   end
 
+  def test_find_all_using_where_with_relation_with_no_selects_and_composite_primary_key_raises
+    order = cpk_orders(:cpk_groceries_order_1)
+    subquery = Cpk::Order.where(Cpk::Order.primary_key => [order.id])
+
+    assert_nothing_raised do
+      Cpk::Order.where(id: subquery.select(:id)).to_a
+    end
+
+    error = assert_raise(ArgumentError) do
+      Cpk::Order.where(id: subquery).to_a
+    end
+
+    assert_equal "Cannot map composite primary key [\"shop_id\", \"id\"] to id", error.message
+  end
+
   def test_find_all_using_where_with_relation_does_not_alter_select_values
     david = authors(:david)