Merge branch '41292-users-stuck-on-a-redirect-loop-after-transferring-project' into 'master'

Resolve "Users stuck on a redirect loop after transferring project"

Closes #41292

See merge request gitlab-org/gitlab-ce!21408

app/services/projects/transfer_service.rb

@@ -43,8 +43,8 @@ module Projects
       @new_path = File.join(@new_namespace.try(:full_path) || '', project.path)
       @old_namespace = project.namespace
 
-      if Project.where(path: project.path, namespace_id: @new_namespace.try(:id)).exists?
-        raise TransferError.new("Project with same path in target namespace already exists")
+      if Project.where(namespace_id: @new_namespace.try(:id)).where('path = ? or name = ?', project.path, project.name).exists?
+        raise TransferError.new("Project with same name or path in target namespace already exists")
       end
 
       if project.has_container_registry_tags?
@@ -118,6 +118,7 @@ module Projects
 
     def rollback_side_effects
       rollback_folder_move
+      project.reload
       update_namespace_and_visibility(@old_namespace)
       write_repository_config(@old_path)
     end

changelogs/unreleased/41292-users-stuck-on-a-redirect-loop-after-transferring-project.yml

+---
+title: Fix project transfer name validation issues causing a redirect loop
+merge_request: 21408
+author:
+type: fixed

spec/services/projects/transfer_service_spec.rb

@@ -169,6 +169,35 @@ describe Projects::TransferService do
     it { expect(project.errors[:new_namespace]).to include('Cannot move project') }
   end
 
+  context 'target namespace containing the same project name' do
+    before do
+      group.add_owner(user)
+      project.update(name: 'new_name')
+
+      create(:project, name: 'new_name', group: group, path: 'other')
+
+      @result = transfer_project(project, user, group)
+    end
+
+    it { expect(@result).to eq false }
+    it { expect(project.namespace).to eq(user.namespace) }
+    it { expect(project.errors[:new_namespace]).to include('Project with same name or path in target namespace already exists') }
+  end
+
+  context 'target namespace containing the same project path' do
+    before do
+      group.add_owner(user)
+
+      create(:project, name: 'other-name', path: project.path, group: group)
+
+      @result = transfer_project(project, user, group)
+    end
+
+    it { expect(@result).to eq false }
+    it { expect(project.namespace).to eq(user.namespace) }
+    it { expect(project.errors[:new_namespace]).to include('Project with same name or path in target namespace already exists') }
+  end
+
   def transfer_project(project, user, new_namespace)
     service = Projects::TransferService.new(project, user)