Add new method Gitlab::Config::Loader::Yaml#load_raw!

- Create a separate method which returns stringified keys.

- Memoizes the return value of the load! method.

lib/gitlab/config/loader/yaml.rb

@@ -21,11 +21,15 @@ module Gitlab
           hash? && !too_big?
         end
 
-        def load!
+        def load_raw!
           raise DataTooLargeError, 'The parsed YAML is too big' if too_big?
           raise Loader::FormatError, 'Invalid configuration format' unless hash?
 
-          @config.deep_symbolize_keys
+          @config
+        end
+
+        def load!
+          @symbolized_config ||= load_raw!.deep_symbolize_keys
         end
 
         private

spec/lib/gitlab/config/loader/yaml_spec.rb

@@ -5,6 +5,16 @@ require 'spec_helper'
 describe Gitlab::Config::Loader::Yaml do
   let(:loader) { described_class.new(yml) }
 
+  let(:yml) do
+    <<~YAML
+    image: 'ruby:2.7'
+    texts:
+      nested_key: 'value1'
+      more_text:
+        more_nested_key: 'value2'
+    YAML
+  end
+
   context 'when yaml syntax is correct' do
     let(:yml) { 'image: ruby:2.7' }
 
@@ -61,6 +71,15 @@ describe Gitlab::Config::Loader::Yaml do
         expect(loader).not_to be_valid
       end
     end
+
+    describe '#load_raw!' do
+      it 'raises error' do
+        expect { loader.load_raw! }.to raise_error(
+          Gitlab::Config::Loader::FormatError,
+          'Invalid configuration format'
+        )
+      end
+    end
   end
 
   # Prevent Billion Laughs attack: https://gitlab.com/gitlab-org/gitlab-foss/issues/56018
@@ -123,4 +142,32 @@ describe Gitlab::Config::Loader::Yaml do
       end
     end
   end
+
+  describe '#load_raw!' do
+    it 'loads keys as strings' do
+      expect(loader.load_raw!).to eq(
+        'image' => 'ruby:2.7',
+        'texts' => {
+          'nested_key' => 'value1',
+          'more_text' => {
+            'more_nested_key' => 'value2'
+          }
+        }
+      )
+    end
+  end
+
+  describe '#load!' do
+    it 'symbolizes keys' do
+      expect(loader.load!).to eq(
+        image: 'ruby:2.7',
+        texts: {
+          nested_key: 'value1',
+          more_text: {
+            more_nested_key: 'value2'
+          }
+        }
+      )
+    end
+  end
 end