Fix Ruby 2.7 keyword args on Repository model

This change improves the `method_missing` implementation.

- The `lookup` delegation is extracted out of `method_missing` to a
separate method and handle caching for `nil` value.
- Other method delegation is handled by `delegate_missing_to` which can
handle keyword arguments for both Ruby 2.7 and 3.0.

app/models/repository.rb

@@ -24,10 +24,10 @@ class Repository
 
   attr_accessor :full_path, :shard, :disk_path, :container, :repo_type
 
-  delegate :ref_name_for_sha, to: :raw_repository
-  delegate :bundle_to_disk, to: :raw_repository
   delegate :lfs_enabled?, to: :container
 
+  delegate_missing_to :raw_repository
+
   CreateTreeError = Class.new(StandardError)
   AmbiguousRefError = Class.new(StandardError)
 
@@ -386,10 +386,6 @@ class Repository
     raw_repository.expire_has_local_branches_cache
   end
 
-  def lookup_cache
-    @lookup_cache ||= {}
-  end
-
   def expire_exists_cache
     expire_method_caches(%i(exists?))
   end
@@ -494,19 +490,12 @@ class Repository
     expire_branches_cache if expire_cache
   end
 
-  def method_missing(msg, *args, &block)
-    if msg == :lookup && !block_given?
-      lookup_cache[msg] ||= {}
-      lookup_cache[msg][args.join(":")] ||= raw_repository.__send__(msg, *args, &block) # rubocop:disable GitlabSecurity/PublicSend
-    else
-      raw_repository.__send__(msg, *args, &block) # rubocop:disable GitlabSecurity/PublicSend
+  def lookup(sha)
+    strong_memoize("lookup_#{sha}") do
+      raw_repository.lookup(sha)
     end
   end
 
-  def respond_to_missing?(method, include_private = false)
-    raw_repository.respond_to?(method, include_private) || super
-  end
-
   def blob_at(sha, path)
     blob = Blob.decorate(raw_repository.blob_at(sha, path), container)
 

spec/models/repository_spec.rb

@@ -123,7 +123,7 @@ RSpec.describe Repository do
           options = { message: 'test tag message\n',
                       tagger: { name: 'John Smith', email: 'john@gmail.com' } }
 
-          rugged_repo(repository).tags.create(annotated_tag_name, 'a48e4fc218069f68ef2e769dd8dfea3991362175', options)
+          rugged_repo(repository).tags.create(annotated_tag_name, 'a48e4fc218069f68ef2e769dd8dfea3991362175', **options)
 
           double_first = double(committed_date: Time.current - 1.second)
           double_last = double(committed_date: Time.current)
@@ -2028,6 +2028,22 @@ RSpec.describe Repository do
     end
   end
 
+  describe '#lookup' do
+    before do
+      allow(repository.raw_repository).to receive(:lookup).and_return('interesting_blob')
+    end
+
+    it 'uses the lookup cache' do
+      2.times.each { repository.lookup('sha1') }
+
+      expect(repository.raw_repository).to have_received(:lookup).once
+    end
+
+    it 'returns the correct value' do
+      expect(repository.lookup('sha1')).to eq('interesting_blob')
+    end
+  end
+
   describe '#after_create' do
     it 'calls expire_status_cache' do
       expect(repository).to receive(:expire_status_cache)