Rename users that had their namespace renamed

db/post_migrate/20170518200835_rename_users_with_renamed_namespace.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RenameUsersWithRenamedNamespace < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  DISALLOWED_ROOT_PATHS = %w[
+    -
+    abuse_reports
+    api
+    autocomplete
+    explore
+    health_check
+    import
+    invites
+    jwt
+    koding
+    member
+    notification_settings
+    oauth
+    sent_notifications
+    unicorn_test
+    uploads
+    users
+  ]
+
+  def up
+    namespace_table = Arel::Table.new('namespaces')
+    users_table = Arel::Table.new('users')
+    matching_path = namespace_table.project(namespace_table[:path])
+                      .join(users_table).on(users_table[:id].eq(namespace_table[:owner_id]))
+                      .where(users_table[:username].not_eq(namespace_table[:path]))
+    path_name = Arel::Nodes::SqlLiteral.new("matching_path.path FROM (#{matching_path.to_sql}) as matching_path")
+
+    update_column_in_batches(:users, :username, path_name) do |table, query|
+      query.where(table[:username].matches_any(DISALLOWED_ROOT_PATHS))
+    end
+  end
+
+  def down
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
-ActiveRecord::Schema.define(version: 20170516183131) do
+ActiveRecord::Schema.define(version: 20170518200835) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"

spec/migrations/rename_users_with_renamed_namespace_spec.rb

+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20170518200835_rename_users_with_renamed_namespace.rb')
+
+describe RenameUsersWithRenamedNamespace, truncate: true do
+  it 'renames a user that had his namespace renamed to the namespace path' do
+    other_user = create(:user, username: 'kodingu')
+
+    user = create(:user, username: "Users0")
+    user.update_attribute(:username, 'Users')
+    user1 = create(:user, username: "import0")
+    user1.update_attribute(:username, 'import')
+
+    described_class.new.up
+
+    expect(user.reload.username).to eq('Users0')
+    expect(user1.reload.username).to eq('import0')
+    expect(other_user.reload.username).to eq('kodingu')
+  end
+end

[Toon Claes]

Could you include a user named api0 and has namespace api0 to ensure it's not renamed?

[Bob Van Landuyt :neckbeard:]

Sure, but that's basically the same test as using kodingu