Merge pull request #31133 from mohsen-alizadeh/sanitize_empty_and_nil_parameters_passed_to_select

sanitize empty and nil parameters to select #31059

2 files changed, 16 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 86882c7ce7..3afa368575 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -231,6 +231,7 @@ module ActiveRecord
     end
 
     def _select!(*fields) # :nodoc:
+      fields.reject!(&:blank?)
       fields.flatten!
       fields.map! do |field|
         klass.attribute_alias?(field) ? klass.attribute_alias(field).to_sym : field
diff --git a/activerecord/test/cases/relation/select_test.rb b/activerecord/test/cases/relation/select_test.rb
new file mode 100644
index 0000000000..0577e6bfdb
--- /dev/null
+++ b/activerecord/test/cases/relation/select_test.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+
+module ActiveRecord
+  class SelectTest < ActiveRecord::TestCase
+    fixtures :posts
+
+    def test_select_with_nil_agrument
+      expected = Post.select(:title).to_sql
+      assert_equal expected, Post.select(nil).select(:title).to_sql
+    end
+  end
+end