make sure to evaluate client name since it might be a proc (#5906) (#5907)

Author: jamis

lib/mongoid/persistence_context.rb

@@ -138,7 +138,7 @@ def client
     # @return [ Symbol ] The client name for this persistence
     #   context.
     def client_name
-      @client_name ||= options[:client] ||
+      @client_name ||= __evaluate__(options[:client]) ||
                          Threaded.client_override ||
                          __evaluate__(storage_options[:client])
     end

spec/mongoid/persistence_context_spec.rb

@@ -584,6 +584,14 @@
         expect(persistence_context.client).to eq(Mongoid::Clients.with_name(:alternative))
       end
 
+      context 'when the client option is a proc' do
+        let(:options) { { client: -> { :alternative } } }
+
+        it 'evaluates the proc' do
+          expect(persistence_context.client).to eq(Mongoid::Clients.with_name(:alternative))
+        end
+      end
+
       context 'when there is a client override' do
         persistence_context_override :client, :other