3 files changed, 12 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 91d486e902..4533f3263f 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -655,6 +655,10 @@ module ActiveRecord
     #    # SELECT `posts`.* FROM `posts`  WHERE (('id = 1' OR 'author_id = 3'))
     #
     def or(other)
+      unless other.is_a? Relation
+        raise ArgumentError, "You have passed #{other.class.name} object to #or. Pass an ActiveRecord::Relation object instead."
+      end
+
       spawn.or!(other)
     end
 
diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
index 3602ee7ba2..84aac3e721 100644
--- a/activerecord/test/cases/batches_test.rb
+++ b/activerecord/test/cases/batches_test.rb
@@ -108,7 +108,7 @@ class EachTest < ActiveRecord::TestCase
     end
   end
 
-  def test_find_in_batches_should_finish_the_end_option
+  def test_find_in_batches_should_end_at_the_finish_option
     assert_queries(6) do
       Post.find_in_batches(batch_size: 1, finish: 5) do |batch|
         assert_kind_of Array, batch
@@ -316,7 +316,7 @@ class EachTest < ActiveRecord::TestCase
     end
   end
 
-  def test_in_batches_should_finish_the_end_option
+  def test_in_batches_should_end_at_the_finish_option
     post = Post.order('id DESC').where('id <= ?', 5).first
     assert_queries(7) do
       relation = Post.in_batches(of: 1, finish: 5, load: true).reverse_each.first
diff --git a/activerecord/test/cases/relation/or_test.rb b/activerecord/test/cases/relation/or_test.rb
index 28a0862f91..ce8c5ca489 100644
--- a/activerecord/test/cases/relation/or_test.rb
+++ b/activerecord/test/cases/relation/or_test.rb
@@ -82,5 +82,11 @@ module ActiveRecord
       assert_equal p.loaded?, true
       assert_equal expected, p.or(Post.where('id = 2')).to_a
     end
+
+    def test_or_with_non_relation_object_raises_error
+      assert_raises ArgumentError do
+        Post.where(id: [1, 2, 3]).or(title: 'Rails')
+      end
+    end
   end
 end