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

9 files changed, 24 insertions, 16 deletions

diff --git a/activerecord/lib/active_record/association_relation.rb b/activerecord/lib/active_record/association_relation.rb
index 5a84792f45..f2b44913db 100644
--- a/activerecord/lib/active_record/association_relation.rb
+++ b/activerecord/lib/active_record/association_relation.rb
@@ -1,7 +1,7 @@
 module ActiveRecord
   class AssociationRelation < Relation
-    def initialize(klass, table, association)
-      super(klass, table)
+    def initialize(klass, table, predicate_builder, association)
+      super(klass, table, predicate_builder)
       @association = association
     end
 
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
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 94d1e07069..65ca1f6fd3 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -248,10 +248,14 @@ module ActiveRecord
           end
       end
 
+      def predicate_builder # :nodoc:
+        @predicate_builder ||= PredicateBuilder.new(self, arel_table)
+      end
+
       private
 
       def relation #:nodoc:
-        relation = Relation.create(self, arel_table)
+        relation = Relation.create(self, arel_table, predicate_builder)
 
         if finder_needs_type_condition?
           relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index a565e923d6..d76dbb43d6 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -147,6 +147,7 @@ module ActiveRecord
         @quoted_table_name = nil
         @arel_table        = nil
         @sequence_name     = nil unless defined?(@explicit_sequence_name) && @explicit_sequence_name
+        @predicate_builder = nil
       end
 
       # Returns a quoted version of the table name, used to construct SQL statements.
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index daafb0b645..2f067d867c 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -16,17 +16,17 @@ module ActiveRecord
 
     include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches, Explain, Delegation
 
-    attr_reader :table, :klass, :loaded
+    attr_reader :table, :klass, :loaded, :predicate_builder
     alias :model :klass
     alias :loaded? :loaded
 
-    def initialize(klass, table, values = {})
+    def initialize(klass, table, predicate_builder, values = {})
       @klass  = klass
       @table  = table
       @values = values
       @offsets = {}
       @loaded = false
-      @predicate_builder = PredicateBuilder.new(klass, table)
+      @predicate_builder = predicate_builder
     end
 
     def initialize_copy(other)
@@ -633,10 +633,6 @@ module ActiveRecord
       "#<#{self.class.name} [#{entries.join(', ')}]>"
     end
 
-    protected
-
-    attr_reader :predicate_builder
-
     private
 
     def exec_queries
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
index a27f990f74..afb0b208c3 100644
--- a/activerecord/lib/active_record/relation/merger.rb
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -22,7 +22,7 @@ module ActiveRecord
       # build a relation to merge in rather than directly merging
       # the values.
       def other
-        other = Relation.create(relation.klass, relation.table)
+        other = Relation.create(relation.klass, relation.table, relation.predicate_builder)
         hash.each { |k, v|
           if k == :joins
             if Hash === v
diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
index 57d66bce4b..01bddea6c9 100644
--- a/activerecord/lib/active_record/relation/spawn_methods.rb
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -67,7 +67,7 @@ module ActiveRecord
     private
 
       def relation_with(values) # :nodoc:
-        result = Relation.create(klass, table, values)
+        result = Relation.create(klass, table, predicate_builder, values)
         result.extend(*extending_values) if extending_values.any?
         result
       end