1 files changed, 40 insertions, 0 deletions
diff --git a/lib/gitlab/config/entry/inheritable.rb b/lib/gitlab/config/entry/inheritable.rb
new file mode 100644
index 00000000000..91ca82e6338
--- /dev/null
+++ b/lib/gitlab/config/entry/inheritable.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Config
+    module Entry
+      ##
+      # Entry that represents an inheritable configs.
+      #
+      module Inheritable
+        InheritError = Class.new(Gitlab::Config::Loader::FormatError)
+
+        def compose!(deps = nil, &blk)
+          super(deps, &blk)
+
+          inherit!(deps)
+        end
+
+        private
+
+        # We inherit config entries from `default:`
+        # if the entry has the `inherit: true` flag set
+        def inherit!(deps)
+          return unless deps
+
+          self.class.nodes.each do |key, factory|
+            next unless factory.inheritable?
+
+            new_entry = overwrite_entry(deps, key, self[key])
+
+            entries[key] = new_entry if new_entry&.specified?
+          end
+        end
+
+        def overwrite_entry(deps, key, current_entry)
+          raise NotImplementedError
+        end
+      end
+    end
+  end
+end