After switch callback not working with nil argument

[jonian]

Hi @rpbaltazar, thank you for maintaining and improving apartment. I found an issue with the after switch callback when passing nil to switch method.

Steps to reproduce

Apartment::Adapters::AbstractAdapter.set_callback :switch, :before do
  puts("Before tenant switch from: #{current}")
end

Apartment::Adapters::AbstractAdapter.set_callback :switch, :after do
  puts("After tenant switch to: #{current}")
end

Apartment::Tenant.switch!(Apartment.default_tenant)
# Before tenant switch from: public
# After tenant switch to: public
# => nil

Apartment::Tenant.switch!
# Before tenant switch from: public
# => "public"

Proposed fixes

module Apartment
  module Adapters
    class AbstractAdapter
      # Original method
      def switch!(tenant = nil)
        run_callbacks :switch do
          return reset if tenant.nil?

          connect_to_new(tenant).tap do
            Apartment.connection.clear_query_cache
          end
        end
      end

      # Proposal 1
      def switch!(tenant = nil)
        run_callbacks :switch do
          if tenant.nil?
            reset
          else
            connect_to_new(tenant).tap do
              Apartment.connection.clear_query_cache
            end
          end
        end
      end

      # Proposal 2
      def switch!(tenant = nil)
        run_callbacks :switch do
          connect_to_new(tenant || default_tenant).tap do
            Apartment.connection.clear_query_cache
          end
        end
      end
    end
  end
end

If you want, I can make a PR with the solution you prefer.

[rpbaltazar]

@jonian thank you for the feedback and nicely spotted. If we sort the sqlite3 adapter connect_to_new receiving nil we can actually just call connect_to_new(tenant) and skip the if else block as all the other adapters handle the scenario in which the tenant is nil