Prevent duplicating `where` clauses when model is extended from an abstract class

Fixes #19528

fix for mysql2 test

better test

1 files changed, 1 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
index 3590b8846e..a1adf8e3ee 100644
--- a/activerecord/lib/active_record/scoping/default.rb
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -100,6 +100,7 @@ module ActiveRecord
         end
 
         def build_default_scope(base_rel = relation) # :nodoc:
+          return if abstract_class?
           if !Base.is_a?(method(:default_scope).owner)
             # The user has defined their own default scope method, so call that
             evaluate_default_scope { default_scope }