fix initial count

activerecord/lib/active_record/associations/alias_tracker.rb

@@ -33,7 +33,7 @@ def self.initial_count_for(connection, name, table_joins)
           elsif join.respond_to? :left
             join.left.name == name ? 1 : 0
           elsif join.is_a?(Hash)
-            join[name]
+            join.fetch(name, 0)
           else
             # this branch is reached by two tests:
             #

activerecord/test/cases/associations/has_many_through_associations_test.rb

@@ -1258,6 +1258,10 @@ def test_has_many_through_with_unscope_should_affect_to_through_scope
     assert_equal [comments(:eager_other_comment1)], authors(:mary).unordered_comments
   end
 
+  def test_has_many_trough_with_scope_should_accept_string_and_hash_join
+    assert_equal authors(:david), Author.joins({ comments_for_first_author: :post }, "inner join posts posts_alias on authors.id = posts_alias.author_id").eager_load(:categories).take
+  end
+
   def test_has_many_through_with_scope_should_respect_table_alias
     family = Family.create!
     users = 3.times.map { User.create! }