Correct errors in counter cache updating

The cache name should be converted to a string when given, not compared
as a symbol. This edge case is already adequately covered by our tests,
but was masked by another issue where we were incorrectly updating the
counter cache twice. When paired with a bug where we didn't update the
counter cache because we couldn't find a match with the name, this made
it look like everything was working fine.

Fixes #10865.

1 files changed, 5 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 b574185561..ca27c9fdde 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -85,7 +85,11 @@ module ActiveRecord
         end
 
         def cached_counter_attribute_name(reflection = reflection())
-          options[:counter_cache] || "#{reflection.name}_count"
+          if reflection.options[:counter_cache]
+            reflection.options[:counter_cache].to_s
+          else
+            "#{reflection.name}_count"
+          end
         end
 
         def update_counter(difference, reflection = reflection())