remove the nil check from set_inverse_instance

methods that call set_inverse_instance with a record will not have to
pay the cost of a nil check on every call

4 files changed, 7 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index ce7d41cf54..67ea489b22 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -104,11 +104,12 @@ module ActiveRecord
 
       # Set the inverse association, if possible
       def set_inverse_instance(record)
-        if record && invertible_for?(record)
+        if invertible_for?(record)
           inverse = record.association(inverse_reflection_for(record).name)
           inverse.target = owner
           inverse.inversed = true
         end
+        record
       end
 
       # Returns the class of the target. belongs_to polymorphic overrides this to look at the
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index e1fa5225b5..5ddff13711 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -12,7 +12,7 @@ module ActiveRecord
 
         update_counters(record)
         replace_keys(record)
-        set_inverse_instance(record)
+        set_inverse_instance(record) if record
 
         @updated = true if record
 
diff --git a/activerecord/lib/active_record/associations/preloader/singular_association.rb b/activerecord/lib/active_record/associations/preloader/singular_association.rb
index 2b5cfda8ce..f60647a81e 100644
--- a/activerecord/lib/active_record/associations/preloader/singular_association.rb
+++ b/activerecord/lib/active_record/associations/preloader/singular_association.rb
@@ -11,7 +11,7 @@ module ActiveRecord
 
             association = owner.association(reflection.name)
             association.target = record
-            association.set_inverse_instance(record)
+            association.set_inverse_instance(record) if record
           end
         end
 
diff --git a/activerecord/lib/active_record/associations/singular_association.rb b/activerecord/lib/active_record/associations/singular_association.rb
index 02dc464536..e4500af5b2 100644
--- a/activerecord/lib/active_record/associations/singular_association.rb
+++ b/activerecord/lib/active_record/associations/singular_association.rb
@@ -39,7 +39,9 @@ module ActiveRecord
         end
 
         def find_target
-          scope.first.tap { |record| set_inverse_instance(record) }
+          if record = scope.first
+            set_inverse_instance record
+          end
         end
 
         def replace(record)