3 files changed, 14 insertions, 7 deletions
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 54215cf88d..862ff201de 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -174,8 +174,6 @@ module ActiveRecord
       # association, it will be used for the query. Otherwise, construct options and pass them with
       # scope to the target class's +count+.
       def count(column_name = nil, count_options = {})
-        return 0 if owner.new_record?
-
         column_name, count_options = nil, column_name if column_name.is_a?(Hash)
 
         if options[:counter_sql] || options[:finder_sql]
@@ -366,6 +364,16 @@ module ActiveRecord
         record
       end
 
+      def scope(opts = {})
+        scope = super()
+        scope.none! if opts.fetch(:nullify, true) && null_scope?
+        scope
+      end
+
+      def null_scope?
+        owner.new_record? && !foreign_key_present?
+      end
+
       private
 
         def custom_counter_sql
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 536e108f0e..50f9fca7c0 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -31,7 +31,7 @@ module ActiveRecord
       def initialize(association) #:nodoc:
         @association = association
         super association.klass, association.klass.arel_table
-        merge! association.scope
+        merge! association.scope(nullify: false)
       end
 
       def target
@@ -835,9 +835,8 @@ module ActiveRecord
       # Returns a <tt>Relation</tt> object for the records in this association
       def scope
         association = @association
-        scope = @association.scope
-        scope.none! if @association.owner.new_record?
-        scope.extending! do
+
+        @association.scope.extending! do
           define_method(:proxy_association) { association }
         end
       end
diff --git a/activerecord/lib/active_record/null_relation.rb b/activerecord/lib/active_record/null_relation.rb
index 4c1c91e3df..f8f7a6c976 100644
--- a/activerecord/lib/active_record/null_relation.rb
+++ b/activerecord/lib/active_record/null_relation.rb
@@ -46,7 +46,7 @@ module ActiveRecord
       {}
     end
 
-    def count
+    def count(*)
       0
     end