load has_many associations keyed off a custom primary key if that key is present but the record is unsaved

2 files changed, 5 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 362f1053cd..af37909c89 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -235,7 +235,7 @@ module ActiveRecord
       # This method is abstract in the sense that it relies on
       # +count_records+, which is a method descendants have to provide.
       def size
-        if owner.new_record? || (loaded? && !options[:uniq])
+        if !find_target? || (loaded? && !options[:uniq])
           target.size
         elsif !loaded? && options[:group]
           load_target.size
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index 3353cdf1ef..c5b90e873a 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -103,6 +103,10 @@ module ActiveRecord
             end
           end
         end
+        
+        def foreign_key_present?
+          owner.attribute_present?(reflection.association_primary_key)
+        end
     end
   end
 end