flags: Drop `update_remote_mirror_inmemory` feature flag

The `udpate_remote_mirror_inmemory` feature flag has been enabled by
default since bfdf0dc2 (Default-enable :update_remote_mirror_inmemory
feature flag, 2021-06-23), which has been released as part of v14.1. We
can thus now remove this feature flag altogether.

Changelog: changed

app/models/remote_mirror.rb

@@ -100,11 +100,11 @@ class RemoteMirror < ApplicationRecord
     update_status == 'started'
   end
 
-  def update_repository(inmemory_remote:)
+  def update_repository
     Gitlab::Git::RemoteMirror.new(
       project.repository.raw,
       remote_name,
-      inmemory_remote ? remote_url : nil,
+      remote_url,
       **options_for_update
     ).update
   end

app/services/projects/update_remote_mirror_service.rb

@@ -43,12 +43,7 @@ module Projects
       # LFS objects must be sent first, or the push has dangling pointers
       send_lfs_objects!(remote_mirror)
 
-      response = if Feature.enabled?(:update_remote_mirror_inmemory, project, default_enabled: :yaml)
-                   remote_mirror.update_repository(inmemory_remote: true)
-                 else
-                   remote_mirror.ensure_remote!
-                   remote_mirror.update_repository(inmemory_remote: false)
-                 end
+      response = remote_mirror.update_repository
 
       if response.divergent_refs.any?
         message = "Some refs have diverged and have not been updated on the remote:"

config/feature_flags/development/update_remote_mirror_inmemory.yml

----
-name: update_remote_mirror_inmemory
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/63962
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/333517
-milestone: '14.0'
-type: development
-group: group::gitaly
-default_enabled: true

spec/models/remote_mirror_spec.rb

@@ -157,34 +157,20 @@ RSpec.describe RemoteMirror, :mailer do
   end
 
   describe '#update_repository' do
-    shared_examples 'an update' do
-      it 'performs update including options' do
-        git_remote_mirror = stub_const('Gitlab::Git::RemoteMirror', spy)
-        mirror = build(:remote_mirror)
-
-        expect(mirror).to receive(:options_for_update).and_return(keep_divergent_refs: true)
-        mirror.update_repository(inmemory_remote: inmemory)
-
-        expect(git_remote_mirror).to have_received(:new).with(
-          mirror.project.repository.raw,
-          mirror.remote_name,
-          inmemory ? mirror.url : nil,
-          keep_divergent_refs: true
-        )
-        expect(git_remote_mirror).to have_received(:update)
-      end
-    end
-
-    context 'with inmemory remote' do
-      let(:inmemory) { true }
-
-      it_behaves_like 'an update'
-    end
-
-    context 'with on-disk remote' do
-      let(:inmemory) { false }
-
-      it_behaves_like 'an update'
+    it 'performs update including options' do
+      git_remote_mirror = stub_const('Gitlab::Git::RemoteMirror', spy)
+      mirror = build(:remote_mirror)
+
+      expect(mirror).to receive(:options_for_update).and_return(keep_divergent_refs: true)
+      mirror.update_repository
+
+      expect(git_remote_mirror).to have_received(:new).with(
+        mirror.project.repository.raw,
+        mirror.remote_name,
+        mirror.url,
+        keep_divergent_refs: true
+      )
+      expect(git_remote_mirror).to have_received(:update)
     end
   end
 

spec/services/projects/update_remote_mirror_service_spec.rb

@@ -13,36 +13,21 @@ RSpec.describe Projects::UpdateRemoteMirrorService do
 
   describe '#execute' do
     let(:retries) { 0 }
-    let(:inmemory) { true }
 
     subject(:execute!) { service.execute(remote_mirror, retries) }
 
     before do
-      stub_feature_flags(update_remote_mirror_inmemory: inmemory)
       project.repository.add_branch(project.owner, 'existing-branch', 'master')
 
       allow(remote_mirror)
         .to receive(:update_repository)
-        .with(inmemory_remote: inmemory)
         .and_return(double(divergent_refs: []))
     end
 
-    context 'with in-memory remote disabled' do
-      let(:inmemory) { false }
+    it 'does not ensure the remote exists' do
+      expect(remote_mirror).not_to receive(:ensure_remote!)
 
-      it 'ensures the remote exists' do
-        expect(remote_mirror).to receive(:ensure_remote!)
-
-        execute!
-      end
-    end
-
-    context 'with in-memory remote enabled' do
-      it 'does not ensure the remote exists' do
-        expect(remote_mirror).not_to receive(:ensure_remote!)
-
-        execute!
-      end
+      execute!
     end
 
     it 'does not fetch the remote repository' do