Fix async queries to work with query cache and other cached async queries

Author: fatkodima

activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb

@@ -629,7 +629,7 @@ def select(sql, name = nil, binds = [], prepare: false, async: false)
 
           result = internal_exec_query(sql, name, binds, prepare: prepare)
           if async
-            FutureResult::Complete.new(result)
+            FutureResult.wrap(result)
           else
             result
           end

activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb

@@ -107,7 +107,7 @@ def select_all(arel, name = nil, binds = [], preparable: nil, async: false) # :n
 
           if async
             result = lookup_sql_cache(sql, name, binds) || super(sql, name, binds, preparable: preparable, async: async)
-            FutureResult::Complete.new(result)
+            FutureResult.wrap(result)
           else
             cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable, async: async) }
           end

activerecord/lib/active_record/future_result.rb

@@ -47,6 +47,15 @@ def flush
 
     Canceled = Class.new(ActiveRecordError)
 
+    def self.wrap(result)
+      case result
+      when self, Complete
+        result
+      else
+        Complete.new(result)
+      end
+    end
+
     delegate :empty?, :to_a, to: :result
     delegate_missing_to :result
 

activerecord/lib/active_record/relation.rb

@@ -1040,7 +1040,7 @@ def exec_queries(&block)
       def exec_main_query(async: false)
         if @none
           if async
-            return FutureResult::Complete.new([])
+            return FutureResult.wrap([])
           else
             return []
           end

activerecord/lib/active_record/result.rb

@@ -195,7 +195,7 @@ def hash_rows
       EMPTY = new([].freeze, [].freeze, {}.freeze).freeze
       private_constant :EMPTY
 
-      EMPTY_ASYNC = FutureResult::Complete.new(EMPTY).freeze
+      EMPTY_ASYNC = FutureResult.wrap(EMPTY).freeze
       private_constant :EMPTY_ASYNC
   end
 end

activerecord/test/cases/calculations_test.rb

@@ -1242,6 +1242,11 @@ def test_calculation_with_query_cache
       count = ShipPart.count
       assert_async_equal count, ShipPart.async_count
     end
+
+    ShipPart.cache do
+      count = ShipPart.async_count
+      assert_async_equal count.value, ShipPart.async_count
+    end
   end
 
   def test_pluck_joined_with_polymorphic_relation