1 files changed, 70 insertions, 0 deletions
diff --git a/lib/gitlab/changelog/template/context.rb b/lib/gitlab/changelog/template/context.rb
new file mode 100644
index 00000000000..8a0796d767e
--- /dev/null
+++ b/lib/gitlab/changelog/template/context.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Changelog
+    module Template
+      # Context is used to provide a binding/context to ERB templates used for
+      # rendering changelogs.
+      #
+      # This class extends BasicObject so that we only expose the bare minimum
+      # needed to render the ERB template.
+      class Context < BasicObject
+        MAX_NESTED_LOOPS = 4
+
+        def initialize(variables)
+          @variables = variables
+          @loop_nesting = 0
+        end
+
+        def get_binding
+          ::Kernel.binding
+        end
+
+        def each(value, &block)
+          max = MAX_NESTED_LOOPS
+
+          if @loop_nesting == max
+            ::Kernel.raise(
+              ::Template::TemplateError.new("You can only nest up to #{max} loops")
+            )
+          end
+
+          @loop_nesting += 1
+          result = value.each(&block) if value.respond_to?(:each)
+          @loop_nesting -= 1
+
+          result
+        end
+
+        # rubocop: disable Style/TrivialAccessors
+        def variables
+          @variables
+        end
+        # rubocop: enable Style/TrivialAccessors
+
+        def read(source, *steps)
+          current = source
+
+          steps.each do |step|
+            case current
+            when ::Hash
+              current = current[step]
+            when ::Array
+              return '' unless step.is_a?(::Integer)
+
+              current = current[step]
+            else
+              break
+            end
+          end
+
+          current
+        end
+
+        def truthy?(value)
+          value.respond_to?(:any?) ? value.any? : !!value
+        end
+      end
+    end
+  end
+end