Fix table name collision due to incorrect alias count on certain joins.

[#6423 state:committed]

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>

2 files changed, 11 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
index 3fea24ebf8..856d826d67 100644
--- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
+++ b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
@@ -82,12 +82,12 @@ module ActiveRecord
               connection = active_record.connection
 
               name = connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}"
-              table_index = aliases[name] + 1
-              name = name[0, connection.table_alias_length-3] + "_#{table_index}" if table_index > 1
+              aliases[name] += 1
+              name = name[0, connection.table_alias_length-3] + "_#{aliases[name]}" if aliases[name] > 1
+            else
+              aliases[name] += 1
             end
 
-            aliases[name] += 1
-
             name
           end
 
diff --git a/activerecord/test/cases/associations/inner_join_association_test.rb b/activerecord/test/cases/associations/inner_join_association_test.rb
index da2a81e98a..8f32902c19 100644
--- a/activerecord/test/cases/associations/inner_join_association_test.rb
+++ b/activerecord/test/cases/associations/inner_join_association_test.rb
@@ -16,6 +16,13 @@ class InnerJoinAssociationTest < ActiveRecord::TestCase
     assert_equal authors(:david), result.first
   end
 
+  def test_construct_finder_sql_does_not_table_name_collide_on_duplicate_associations
+    assert_nothing_raised do
+      sql = Person.joins(:agents => {:agents => :agents}).joins(:agents => {:agents => {:primary_contact => :agents}}).to_sql
+      assert_match(/agents_people_4/i, sql)
+    end
+  end
+
   def test_construct_finder_sql_ignores_empty_joins_hash
     sql = Author.joins({}).to_sql
     assert_no_match(/JOIN/i, sql)