Eliminate lease_connection call in Arel

Author: byroot

activerecord/lib/arel/nodes/node.rb

@@ -147,8 +147,9 @@ def invert
       # Maybe we should just use `Table.engine`?  :'(
       def to_sql(engine = Table.engine)
         collector = Arel::Collectors::SQLString.new
-        collector = engine.lease_connection.visitor.accept self, collector
-        collector.value
+        engine.with_connection do |connection|
+          connection.visitor.accept(self, collector).value
+        end
       end
 
       def fetch_attribute

activerecord/lib/arel/tree_manager.rb

@@ -52,8 +52,9 @@ def to_dot
 
     def to_sql(engine = Table.engine)
       collector = Arel::Collectors::SQLString.new
-      collector = engine.lease_connection.visitor.accept @ast, collector
-      collector.value
+      engine.with_connection do |connection|
+        engine.lease_connection.visitor.accept(@ast, collector).value
+      end
     end
 
     def initialize_copy(other)

activerecord/test/cases/arel/support/fake_record.rb

@@ -129,6 +129,10 @@ def initialize
       @connection_pool = ConnectionPool.new
     end
 
+    def with_connection(...)
+      connection_pool.with_connection(...)
+    end
+
     def lease_connection
       connection_pool.lease_connection
     end