Fix FinderMethods#last unscoped primary key

Fixes table.joins(:relation).last(N) breaking on sqlite

Conflicts:
	activerecord/CHANGELOG.md
	activerecord/test/cases/finder_test.rb

actionpack/CHANGELOG.md

@@ -12,7 +12,6 @@
 
     *Kassio Borges*
 
-
 *   Fix `ActionDispatch::Assertions::ResponseAssertions#assert_redirected_to`
     does not show user-supplied message.
 

activerecord/CHANGELOG.md

@@ -1,4 +1,9 @@
 ## unreleased ##
+*   Fix `FinderMethods#last` unscoped primary key.
+
+    Fixes #11917.
+
+    *Eugene Kalenkovich*
 
 *   Load fixtures from linked folders.
 

activerecord/lib/active_record/relation/finder_methods.rb

@@ -134,8 +134,8 @@ module ActiveRecord
     def last(*args)
       if args.any?
         if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash))
-          if order_values.empty?
-            order("#{primary_key} DESC").limit(*args).reverse
+          if order_values.empty? && primary_key
+            order("#{quoted_table_name}.#{quoted_primary_key} DESC").limit(*args).reverse
           else
             to_a.last(*args)
           end

activerecord/test/cases/finder_test.rb

@@ -305,10 +305,24 @@ class FinderTest < ActiveRecord::TestCase
     assert_sql(/LIMIT 5|ROWNUM <= 5/) { Topic.last(5).entries }
   end
 
+  def test_last_should_use_default_order
+    assert_sql(/ORDER BY .topics.\..id. DESC/) { Topic.last }
+  end
+
+  def test_last_with_integer_should_use_default_order
+    assert_sql(/ORDER BY .topics.\..id. DESC/) { Topic.last(5).entries }
+  end
+
   def test_last_with_integer_and_order_should_keep_the_order
     assert_equal Topic.order("title").to_a.last(2), Topic.order("title").last(2)
   end
 
+  def test_last_with_integer_should_work_with_joins
+    assert_nothing_raised do
+      Post.joins(:comments).last(2)
+    end
+  end
+
   def test_last_with_integer_and_order_should_not_use_sql_limit
     query = assert_sql { Topic.order("title").last(5).entries }
     assert_equal 1, query.length