Merge branch 'fix/import-user-validation-error' into 'master'

Fix user validation error in Import/Export

Closes #23833

See merge request !8909

changelogs/unreleased/fix-import-user-validation-error.yml

@@ -0,0 +1,4 @@
+---
+title: Remove old project members when retrying an export
+merge_request: 
+author: 

lib/gitlab/import_export/members_mapper.rb

@@ -41,6 +41,8 @@ module Gitlab
       end
 
       def ensure_default_member!
+        @project.project_members.destroy_all
+
         ProjectMember.create!(user: @user, access_level: ProjectMember::MASTER, source_id: @project.id, importing: true)
       end
 

spec/lib/gitlab/import_export/members_mapper_spec.rb

@@ -92,5 +92,29 @@ describe Gitlab::ImportExport::MembersMapper, services: true do
         expect(members_mapper.map[exported_user_id]).to eq(user2.id)
       end
     end
+
+    context 'importer same as group member' do
+      let(:user2) { create(:admin, authorized_projects_populated: true) }
+      let(:group) { create(:group) }
+      let(:project) { create(:empty_project, :public, name: 'searchable_project', namespace: group) }
+      let(:members_mapper) do
+        described_class.new(
+          exported_members: exported_members, user: user2, project: project)
+      end
+
+      before do
+        group.add_users([user, user2], GroupMember::DEVELOPER)
+      end
+
+      it 'maps the project member' do
+        expect(members_mapper.map[exported_user_id]).to eq(user2.id)
+      end
+
+      it 'maps the project member if it already exists' do
+        project.add_master(user2)
+
+        expect(members_mapper.map[exported_user_id]).to eq(user2.id)
+      end
+    end
   end
 end