Fix `relation.create` to avoid leaking scope to initialization block and callbacks

`relation.create` populates scope attributes to new record by `scoping`,
it is necessary to assign the scope attributes to the record and to find
STI subclass from the scope attributes.

But the effect of `scoping` is class global, it was caused undesired
behavior that pollute all class level querying methods in initialization
block and callbacks (`after_initialize`, `before_validation`,
`before_save`, etc), which are user provided code.

To avoid the leaking scope issue, restore the original current scope
before initialization block and callbacks are invoked.

Fixes #9894.
Fixes #17577.
Closes #31526.

1 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 4938b6865f..363593ca19 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1535,7 +1535,7 @@ class BasicsTest < ActiveRecord::TestCase
     Bird.create!(name: "Bluejay")
 
     ActiveRecord::Base.connection.while_preventing_writes do
-      assert_queries(2) { Bird.where(name: "Bluejay").explain }
+      assert_nothing_raised { Bird.where(name: "Bluejay").explain }
     end
   end