Move TagNames to mandatory through Gitaly

Closes: https://gitlab.com/gitlab-org/gitaly/issues/220

lib/gitlab/git/repository.rb

@@ -150,12 +150,8 @@ module Gitlab
       # Returns an Array of branch names
       # sorted by name ASC
       def branch_names
-        gitaly_migrate(:branch_names, status: Gitlab::GitalyClient::MigrationStatus::OPT_OUT) do |is_enabled|
-          if is_enabled
+        wrapped_gitaly_errors do
           gitaly_ref_client.branch_names
-          else
-            branches.map(&:name)
-          end
         end
       end
 
@@ -268,8 +264,10 @@ module Gitlab
 
       # Returns an Array of tag names
       def tag_names
+        wrapped_gitaly_errors do
           gitaly_ref_client.tag_names
         end
+      end
 
       # Returns an Array of Tags
       #
@@ -1420,6 +1418,16 @@ module Gitlab
         raise CommandError.new(e)
       end
 
+      def wrapped_gitaly_errors(&block)
+        yield block
+      rescue GRPC::NotFound => e
+        raise NoRepository.new(e)
+      rescue GRPC::InvalidArgument => e
+        raise ArgumentError.new(e)
+      rescue GRPC::BadStatus => e
+        raise CommandError.new(e)
+      end
+
       def clean_stale_repository_files
         gitaly_migrate(:repository_cleanup, status: Gitlab::GitalyClient::MigrationStatus::OPT_OUT) do |is_enabled|
           gitaly_repository_client.cleanup if is_enabled && exists?