repository: Remove `#ref_name_for_sha`

Remove the function `#ref_name_for_sha`, which isn't used anywhere since
fa0b4321 (Added validation to AfterCreateService, 2020-03-02) . This
removes the last callsite of Gitaly's FindRefName RPC.

lib/gitlab/git/repository.rb

@@ -491,13 +491,6 @@ module Gitlab
         []
       end
 
-      # Returns a RefName for a given SHA
-      def ref_name_for_sha(ref_path, sha)
-        raise ArgumentError, "sha can't be empty" unless sha.present?
-
-        gitaly_ref_client.find_ref_name(sha, ref_path)
-      end
-
       # Get refs hash which key is the commit id
       # and value is a Gitlab::Git::Tag or Gitlab::Git::Branch
       # Note that both inherit from Gitlab::Git::Ref

lib/gitlab/gitaly_client/ref_service.rb

@@ -52,16 +52,6 @@ module Gitlab
         consume_refs_response(response) { |name| Gitlab::Git.tag_name(name) }
       end
 
-      def find_ref_name(commit_id, ref_prefix)
-        request = Gitaly::FindRefNameRequest.new(
-          repository: @gitaly_repo,
-          commit_id: commit_id,
-          prefix: ref_prefix
-        )
-        response = GitalyClient.call(@storage, :ref_service, :find_ref_name, request, timeout: GitalyClient.medium_timeout)
-        encode!(response.name.dup)
-      end
-
       def list_new_blobs(newrev, limit = 0, dynamic_timeout: nil)
         request = Gitaly::ListNewBlobsRequest.new(
           repository: @gitaly_repo,

spec/lib/gitlab/git/repository_spec.rb

@@ -1132,28 +1132,6 @@ RSpec.describe Gitlab::Git::Repository, :seed_helper do
     end
   end
 
-  describe '#ref_name_for_sha' do
-    let(:ref_path) { 'refs/heads' }
-    let(:sha) { repository.find_branch('master').dereferenced_target.id }
-    let(:ref_name) { 'refs/heads/master' }
-
-    it 'returns the ref name for the given sha' do
-      expect(repository.ref_name_for_sha(ref_path, sha)).to eq(ref_name)
-    end
-
-    it "returns an empty name if the ref doesn't exist" do
-      expect(repository.ref_name_for_sha(ref_path, "000000")).to eq("")
-    end
-
-    it "raise an exception if the ref is empty" do
-      expect { repository.ref_name_for_sha(ref_path, "") }.to raise_error(ArgumentError)
-    end
-
-    it "raise an exception if the ref is nil" do
-      expect { repository.ref_name_for_sha(ref_path, nil) }.to raise_error(ArgumentError)
-    end
-  end
-
   describe '#branches' do
     subject { repository.branches }
 

spec/lib/gitlab/gitaly_client/ref_service_spec.rb

@@ -189,13 +189,6 @@ RSpec.describe Gitlab::GitalyClient::RefService do
     end
   end
 
-  describe '#find_ref_name', :seed_helper do
-    subject { client.find_ref_name(SeedRepo::Commit::ID, 'refs/heads/master') }
-
-    it { is_expected.to be_utf8 }
-    it { is_expected.to eq('refs/heads/master') }
-  end
-
   describe '#ref_exists?', :seed_helper do
     it 'finds the master branch ref' do
       expect(client.ref_exists?('refs/heads/master')).to eq(true)

spec/models/repository_spec.rb

@@ -142,15 +142,6 @@ RSpec.describe Repository do
     end
   end
 
-  describe '#ref_name_for_sha' do
-    it 'returns the ref' do
-      allow(repository.raw_repository).to receive(:ref_name_for_sha)
-        .and_return('refs/environments/production/77')
-
-      expect(repository.ref_name_for_sha('bla', '0' * 40)).to eq 'refs/environments/production/77'
-    end
-  end
-
   describe '#ref_exists?' do
     context 'when ref exists' do
       it 'returns true' do