Running yarn install before running the update checkoer (#11011)

* Adding yarn install in file_fetcher.rb

* removing unused require

* fixing the sorbet error.

* Creating a .yarn/cache folder makes the cli run success.

* sorbet error fixes.

* Adding check for mono repo.

* Removed the monorepo check.

* Delete smoke.yml

---------

Co-authored-by: “Thavachelvam <“[email protected]”>

npm_and_yarn/lib/dependabot/npm_and_yarn/file_fetcher.rb

@@ -107,6 +107,7 @@ def yarn_files
         fetched_yarn_files << yarn_lock if yarn_lock
         fetched_yarn_files << yarnrc if yarnrc
         fetched_yarn_files << yarnrc_yml if yarnrc_yml
+        create_yarn_cache
         fetched_yarn_files
       end
 
@@ -655,6 +656,19 @@ def parsed_lerna_json
       rescue JSON::ParserError
         raise Dependabot::DependencyFileNotParseable, T.must(lerna_json).path
       end
+
+      sig { void }
+      def create_yarn_cache
+        if repo_contents_path.nil?
+          Dependabot.logger.info("Repository contents path is nil")
+        elsif Dir.exist?(T.must(repo_contents_path))
+          Dir.chdir(T.must(repo_contents_path)) do
+            FileUtils.mkdir_p(".yarn/cache")
+          end
+        else
+          Dependabot.logger.info("Repository contents path does not exist")
+        end
+      end
     end
   end
 end

npm_and_yarn/spec/dependabot/npm_and_yarn/file_fetcher_spec.rb

@@ -90,6 +90,9 @@
           File.join(repo_contents_path, ".pnp.cjs")
         )
       ).to start_with("version https://git-lfs.github.com/spec/v1")
+
+      # Ensure .yarn directory contains .cache directory
+      expect(Dir.exist?(File.join(repo_contents_path, ".yarn", "cache"))).to be true
     end
   end