Avoid passing unnecessary arguments to relation

Most of the time the table and predicate_builder
passed to Relation.new are exactly the
arel_table and predicate builder of the
given klass. This uses klass.arel_table
and klass.predicate_builder as the defaults,
so we don't have to pass them in most cases.

This does change the signaure of both Relation and
AssocationRelation. Are we ok with that?

8 files changed, 17 insertions, 9 deletions

diff --git a/activerecord/lib/active_record/association_relation.rb b/activerecord/lib/active_record/association_relation.rb
index 2b0b2864bc..403667fb70 100644
--- a/activerecord/lib/active_record/association_relation.rb
+++ b/activerecord/lib/active_record/association_relation.rb
@@ -2,8 +2,8 @@
 
 module ActiveRecord
   class AssociationRelation < Relation
-    def initialize(klass, table, predicate_builder, association)
-      super(klass, table, predicate_builder)
+    def initialize(klass, association)
+      super(klass)
       @association = association
     end
 
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index ca1f9f1650..7667c6ed8b 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -124,7 +124,7 @@ 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, klass.predicate_builder, self).merge!(klass.all)
+        AssociationRelation.create(klass, self).merge!(klass.all)
       end
 
       def extensions
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 8b4a48a38c..9a30198b95 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
     class CollectionProxy < Relation
       def initialize(klass, association) #:nodoc:
         @association = association
-        super klass, klass.arel_table, klass.predicate_builder
+        super klass
 
         extensions = association.extensions
         extend(*extensions) if extensions.any?
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 88810cb328..2c65f618dc 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -281,7 +281,7 @@ module ActiveRecord
         end
 
         def relation
-          relation = Relation.create(self, arel_table, predicate_builder)
+          relation = Relation.create(self)
 
           if finder_needs_type_condition? && !ignore_default_scope?
             relation.where!(type_condition)
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index c28e31a3da..e640d75d2f 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -291,7 +291,11 @@ module ActiveRecord
       end
 
       def build_scope(table, predicate_builder = predicate_builder(table))
-        Relation.create(klass, table, predicate_builder)
+        Relation.create(
+          klass,
+          table: table,
+          predicate_builder: predicate_builder
+        )
       end
 
       def join_primary_key(*)
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 10be583ef4..d71c430045 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -22,7 +22,7 @@ module ActiveRecord
     alias :loaded? :loaded
     alias :locked? :lock_value
 
-    def initialize(klass, table, predicate_builder, values = {})
+    def initialize(klass, table: klass.arel_table, predicate_builder: klass.predicate_builder, values: {})
       @klass  = klass
       @table  = table
       @values = values
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
index ebdd4144bb..25510d4a57 100644
--- a/activerecord/lib/active_record/relation/merger.rb
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -23,7 +23,11 @@ module ActiveRecord
       # build a relation to merge in rather than directly merging
       # the values.
       def other
-        other = Relation.create(relation.klass, relation.table, relation.predicate_builder)
+        other = Relation.create(
+          relation.klass,
+          table: relation.table,
+          predicate_builder: 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 617d8de8b2..562e04194c 100644
--- a/activerecord/lib/active_record/relation/spawn_methods.rb
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -69,7 +69,7 @@ module ActiveRecord
     private
 
       def relation_with(values)
-        result = Relation.create(klass, table, predicate_builder, values)
+        result = Relation.create(klass, values: values)
         result.extend(*extending_values) if extending_values.any?
         result
       end