Fix eager loading association with scope including joins

Fixes #28324.

2 files changed, 21 insertions, 11 deletions

diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
index d0c1848079..b14ddfeeeb 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_association.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -34,13 +34,19 @@ module ActiveRecord
             table = tables.shift
             klass = reflection.klass
 
-            join_scope = reflection.join_scope(table, foreign_table, foreign_klass)
-
-            binds.concat join_scope.bound_attributes
-            constraint = join_scope.arel.constraints
+            constraint = reflection.build_join_constraint(table, foreign_table)
 
             joins << table.create_join(table, table.create_on(constraint), join_type)
 
+            join_scope = reflection.join_scope(table, foreign_klass)
+
+            if join_scope.arel.constraints.any?
+              binds.concat join_scope.bound_attributes
+              joins.concat join_scope.arel.join_sources
+              right = joins.last.right
+              right.expr = right.expr.and(join_scope.arel.constraints)
+            end
+
             # The current table in this iteration becomes the foreign table in the next
             foreign_table, foreign_klass = table, klass
           end
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 8ff2f50fdb..a453ca55c7 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -185,19 +185,23 @@ module ActiveRecord
       end
       deprecate :scope_chain
 
-      def join_scope(table, foreign_table, foreign_klass)
-        predicate_builder = predicate_builder(table)
-        scope_chain_items = join_scopes(table, predicate_builder)
-        klass_scope       = klass_join_scope(table, predicate_builder)
-
+      def build_join_constraint(table, foreign_table)
         key         = join_keys.key
         foreign_key = join_keys.foreign_key
 
-        klass_scope.where!(table[key].eq(foreign_table[foreign_key]))
+        constraint = table[key].eq(foreign_table[foreign_key])
 
         if klass.finder_needs_type_condition?
-          klass_scope.where!(klass.send(:type_condition, table))
+          table.create_and([constraint, klass.send(:type_condition, table)])
+        else
+          constraint
         end
+      end
+
+      def join_scope(table, foreign_klass)
+        predicate_builder = predicate_builder(table)
+        scope_chain_items = join_scopes(table, predicate_builder)
+        klass_scope       = klass_join_scope(table, predicate_builder)
 
         if type
           klass_scope.where!(type => foreign_klass.base_class.sti_name)