Fix a false positive for Rails/DynamicFindBy

CHANGELOG.md

@@ -9,6 +9,7 @@
 * [#338](https://github.com/rubocop-hq/rubocop-rails/issues/338): Fix a false positive for `Rails/IndexBy` and `Rails/IndexWith` when the `each_with_object` hash is used in the transformed key or value. ([@eugeneius][])
 * [#351](https://github.com/rubocop-hq/rubocop-rails/pull/351): Add `<>` operator to `Rails/WhereNot` cop. ([@Tietew][])
 * [#352](https://github.com/rubocop-hq/rubocop-rails/pull/352): Do not register offense if given a splatted hash. ([@dvandersluis][])
+* [#346](https://github.com/rubocop-hq/rubocop-rails/pull/346): Fix a false positive for `Rails/DynamicFindBy` when any of the arguments are splat argument. ([@koic][])
 
 ## 2.8.0 (2020-09-04)
 

lib/rubocop/cop/rails/dynamic_find_by.rb

@@ -41,6 +41,7 @@ def on_send(node)
           method_name = node.method_name
           static_name = static_method_name(method_name)
           return unless static_name
+          return if node.arguments.any?(&:splat_type?)
 
           add_offense(node,
                       message: format(MSG, static_name: static_name,

spec/rubocop/cop/rails/dynamic_find_by_spec.rb

@@ -133,6 +133,14 @@
     expect_no_offenses('User.find_by(name: name)')
   end
 
+  it 'accepts splat argument' do
+    expect_no_offenses('User.find_by_scan(*args)')
+  end
+
+  it 'accepts any of the arguments are splat argument' do
+    expect_no_offenses('User.find_by_foo_and_bar(arg, *args)')
+  end
+
   it 'accepts method in whitelist' do
     expect_no_offenses(<<~RUBY)
       User.find_by_sql(["select * from users where name = ?", name])