Ensure that inverse associations are set before running callbacks

If a parent association was accessed in an `after_find` or
`after_initialize` callback, it would always end up loading the
association, and then immediately overwriting the association we just
loaded. If this occurred in a way that the parent's `current_scope` was
set to eager load the child, this would result in an infinite loop and
eventually overflow the stack.

For records that are created with `.new`, we have a mechanism to
perform an action before the callbacks are run. I've introduced the same
code path for records created with `instantiate`, and updated all code
which sets inverse instances on newly loaded associations to use this
block instead.

Fixes #26320.

1 files changed, 4 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index d7de1032b6..6d571cf026 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -562,8 +562,8 @@ module ActiveRecord
     # return value is the relation itself, not the records.
     #
     #   Post.where(published: true).load # => #<ActiveRecord::Relation>
-    def load
-      exec_queries unless loaded?
+    def load(&block)
+      exec_queries(&block) unless loaded?
 
       self
     end
@@ -678,8 +678,8 @@ module ActiveRecord
 
     private
 
-      def exec_queries
-        @records = eager_loading? ? find_with_associations.freeze : @klass.find_by_sql(arel, bound_attributes).freeze
+      def exec_queries(&block)
+        @records = eager_loading? ? find_with_associations.freeze : @klass.find_by_sql(arel, bound_attributes, &block).freeze
 
         preload = preload_values
         preload +=  includes_values unless eager_loading?