Eliminate lease_connection call in JoinAssociation

Author: byroot

activerecord/lib/active_record/associations/join_dependency/join_association.rb

@@ -37,39 +37,41 @@ def join_constraints(foreign_table, foreign_klass, join_type, alias_tracker)
             chain << [reflection, table]
           end
 
-          # The chain starts with the target table, but we want to end with it here (makes
-          # more sense in this context), so we reverse
-          chain.reverse_each do |reflection, table|
-            klass = reflection.klass
+          base_klass.with_connection do |connection|
+            # The chain starts with the target table, but we want to end with it here (makes
+            # more sense in this context), so we reverse
+            chain.reverse_each do |reflection, table|
+              klass = reflection.klass
 
-            scope = reflection.join_scope(table, foreign_table, foreign_klass)
+              scope = reflection.join_scope(table, foreign_table, foreign_klass)
 
-            unless scope.references_values.empty?
-              associations = scope.eager_load_values | scope.includes_values
+              unless scope.references_values.empty?
+                associations = scope.eager_load_values | scope.includes_values
 
-              unless associations.empty?
-                scope.joins! scope.construct_join_dependency(associations, Arel::Nodes::OuterJoin)
+                unless associations.empty?
+                  scope.joins! scope.construct_join_dependency(associations, Arel::Nodes::OuterJoin)
+                end
               end
-            end
 
-            arel = scope.arel(alias_tracker.aliases)
-            nodes = arel.constraints.first
+              arel = scope.arel(alias_tracker.aliases)
+              nodes = arel.constraints.first
 
-            if nodes.is_a?(Arel::Nodes::And)
-              others = nodes.children.extract! do |node|
-                !Arel.fetch_attribute(node) { |attr| attr.relation.name == table.name }
+              if nodes.is_a?(Arel::Nodes::And)
+                others = nodes.children.extract! do |node|
+                  !Arel.fetch_attribute(node) { |attr| attr.relation.name == table.name }
+                end
               end
-            end
 
-            joins << join_type.new(table, Arel::Nodes::On.new(nodes))
+              joins << join_type.new(table, Arel::Nodes::On.new(nodes))
 
-            if others && !others.empty?
-              joins.concat arel.join_sources
-              append_constraints(joins.last, others)
-            end
+              if others && !others.empty?
+                joins.concat arel.join_sources
+                append_constraints(connection, joins.last, others)
+              end
 
-            # The current table in this iteration becomes the foreign table in the next
-            foreign_table, foreign_klass = table, klass
+              # The current table in this iteration becomes the foreign table in the next
+              foreign_table, foreign_klass = table, klass
+            end
           end
 
           joins
@@ -88,10 +90,10 @@ def strict_loading?
         end
 
         private
-          def append_constraints(join, constraints)
+          def append_constraints(connection, join, constraints)
             if join.is_a?(Arel::Nodes::StringJoin)
               join_string = Arel::Nodes::And.new(constraints.unshift join.left)
-              join.left = Arel.sql(base_klass.lease_connection.visitor.compile(join_string))
+              join.left = Arel.sql(connection.visitor.compile(join_string))
             else
               right = join.right
               right.expr = Arel::Nodes::And.new(constraints.unshift right.expr)