Fix deleting through records when using has_many through with `source_type`

Currently deleting through records doesn't respect `source_type`. It
should not be ignored in that case.

Related #23209.
Fixes #24116.

1 files changed, 6 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
index bce2a95ce1..249eb1775b 100644
--- a/activerecord/lib/active_record/associations/through_association.rb
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -38,24 +38,22 @@ module ActiveRecord
         def construct_join_attributes(*records)
           ensure_mutable
 
-          if source_reflection.association_primary_key(reflection.klass) == reflection.klass.primary_key
+          association_primary_key = source_reflection.association_primary_key(reflection.klass)
+
+          if association_primary_key == reflection.klass.primary_key && !options[:source_type]
             join_attributes = { source_reflection.name => records }
           else
             join_attributes = {
-              source_reflection.foreign_key =>
-                records.map { |record|
-                  record.send(source_reflection.association_primary_key(reflection.klass))
-                }
+              source_reflection.foreign_key => records.map(&association_primary_key.to_sym)
             }
           end
 
           if options[:source_type]
-            join_attributes[source_reflection.foreign_type] =
-              records.map { |record| record.class.base_class.name }
+            join_attributes[source_reflection.foreign_type] = [ options[:source_type] ]
           end
 
           if records.count == 1
-            Hash[join_attributes.map { |k, v| [k, v.first] }]
+            join_attributes.transform_values!(&:first)
           else
             join_attributes
           end