Allow `autosave: true` to be used with inverse of

With the changes in #25337, double save bugs are pretty much impossible,
so we can just lift this restriction with pretty much no change. There
were a handful of cases where we were relying on specific quirks in
tests that had to be updated. The change to has_one associations was due
to a particularly interesting test where an autosaved has_one
association was replaced with a new child, where the child failed to
save but the test wanted to check that the parent id persisted to `nil`.

I think this is almost certainly the wrong behavior, and I may change
that behavior later. But ultimately the root cause was because we never
remove the parent in memory when nullifying the child. This makes #23197
no longer needed, but it is what we'll do to fix some issues on 5.0

Close #23197

2 files changed, 2 insertions, 1 deletions

diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index 483d1162bc..862f33a1a0 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -601,7 +601,7 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
 
     new_ship = Ship.create(name: "new name")
     assert_queries(2) do
-      # One query for updating name and second query for updating pirate_id
+      # One query to nullify the old ship, one query to update the new ship
       pirate.ship = new_ship
     end
 
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index 80e76caaaa..a3f82ed49d 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -792,6 +792,7 @@ class TestDestroyAsPartOfAutosaveAssociation < ActiveRecord::TestCase
     end
 
     @ship.pirate.catchphrase = "Changed Catchphrase"
+    @ship.name_will_change!
 
     assert_raise(RuntimeError) { assert !@pirate.save }
     assert_not_nil @pirate.reload.ship