`scope` now raises on "dangerous" name conflicts

Similar to dangerous attribute methods, a scope name conflict is
dangerous if it conflicts with an existing class method defined within
`ActiveRecord::Base` but not its ancestors.

See also #13389.

*Godfrey Chan*, *Philippe Creux*

1 files changed, 57 insertions, 0 deletions

diff --git a/activerecord/test/cases/scoping/named_scoping_test.rb b/activerecord/test/cases/scoping/named_scoping_test.rb
index 086977d9a2..9dc26cfd4d 100644
--- a/activerecord/test/cases/scoping/named_scoping_test.rb
+++ b/activerecord/test/cases/scoping/named_scoping_test.rb
@@ -266,6 +266,63 @@ class NamedScopingTest < ActiveRecord::TestCase
     assert_equal 'lifo', topic.author_name
   end
 
+  def test_reserved_scope_names
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "topics"
+
+      scope :approved, -> { where(approved: true) }
+
+      class << self
+        public
+          def pub; end
+
+        private
+          def pri; end
+
+        protected
+          def pro; end
+      end
+    end
+
+    subklass = Class.new(klass)
+
+    conflicts = [
+      :create,        # public class method on AR::Base
+      :relation,      # private class method on AR::Base
+      :new,           # redefined class method on AR::Base
+      :all,           # a default scope
+    ]
+
+    non_conflicts = [
+      :find_by_title, # dynamic finder method
+      :approved,      # existing scope
+      :pub,           # existing public class method
+      :pri,           # existing private class method
+      :pro,           # existing protected class method
+      :open,          # a ::Kernel method
+    ]
+
+    conflicts.each do |name|
+      assert_raises(ArgumentError, "scope `#{name}` should not be allowed") do
+        klass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+
+      assert_raises(ArgumentError, "scope `#{name}` should not be allowed") do
+        subklass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+    end
+
+    non_conflicts.each do |name|
+      assert_nothing_raised do
+        klass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+
+      assert_nothing_raised do
+        subklass.class_eval { scope name, ->{ where(approved: true) } }
+      end
+    end
+  end
+
   # Method delegation for scope names which look like /\A[a-zA-Z_]\w*[!?]?\z/
   # has been done by evaluating a string with a plain def statement. For scope
   # names which contain spaces this approach doesn't work.