Require explicit counter_cache option for has_many

Previously has_many associations assumed a counter_cache was to be used
based on the presence of an appropriately named column. This is
inconsistent, since the inverse belongs_to association will not make
this assumption. See issues #19042 #8446.
This commit checks for the presence of the counter_cache key in the
options of either the has_many or belongs_to association as well as
ensuring that the *_count column is present.

1 files changed, 8 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index ca27c9fdde..794eb9e183 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -80,8 +80,15 @@ module ActiveRecord
           [association_scope.limit_value, count].compact.min
         end
 
+
+        # Returns whether a counter cache should be used for this association.
+        #
+        # The counter_cache option must be given on either the owner or inverse
+        # association, and the column must be present on the owner.
         def has_cached_counter?(reflection = reflection())
-          owner.attribute_present?(cached_counter_attribute_name(reflection))
+          if reflection.options[:counter_cache] || (inverse = inverse_which_updates_counter_cache(reflection)) && inverse.options[:counter_cache]
+            owner.attribute_present?(cached_counter_attribute_name(reflection))
+          end
         end
 
         def cached_counter_attribute_name(reflection = reflection())