Inject the `PredicateBuilder` into the `Relation` instance

Construction of relations can be a hotspot, we don't want to create one
of these in the constructor. This also allows us to do more expensive
things in the predicate builder's constructor, since it's created once
per AR::Base subclass

3 files changed, 11 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index f1c36cd047..0d8e4ba870 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -121,7 +121,7 @@ module ActiveRecord
       # Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the
       # through association's scope)
       def target_scope
-        AssociationRelation.create(klass, klass.arel_table, self).merge!(klass.all)
+        AssociationRelation.create(klass, klass.arel_table, klass.predicate_builder, self).merge!(klass.all)
       end
 
       # Loads the \target if needed and returns it.
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 060b2278d9..e1c01cfe06 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -32,7 +32,7 @@ module ActiveRecord
 
       def initialize(klass, association) #:nodoc:
         @association = association
-        super klass, klass.arel_table
+        super klass, klass.arel_table, klass.predicate_builder
         merge! association.scope(nullify: false)
       end
 
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
index 5dede5527d..1d7b3e90c0 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_association.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -43,16 +43,23 @@ module ActiveRecord
 
             constraint = build_constraint(klass, table, key, foreign_table, foreign_key)
 
+            predicate_builder = PredicateBuilder.new(klass, table)
             scope_chain_items = scope_chain[scope_chain_index].map do |item|
               if item.is_a?(Relation)
                 item
               else
-                ActiveRecord::Relation.create(klass, table).instance_exec(node, &item)
+                ActiveRecord::Relation.create(klass, table, predicate_builder)
+                  .instance_exec(node, &item)
               end
             end
             scope_chain_index += 1
 
-            scope_chain_items.concat [klass.send(:build_default_scope, ActiveRecord::Relation.create(klass, table))].compact
+            relation = ActiveRecord::Relation.create(
+              klass,
+              table,
+              predicate_builder,
+            )
+            scope_chain_items.concat [klass.send(:build_default_scope, relation)].compact
 
             rel = scope_chain_items.inject(scope_chain_items.shift) do |left, right|
               left.merge right