Ensure cyclic associations w/ autosave don't cause duplicate errors

This code is so fucked. Things that cause this bug not to replicate:

- Defining the validation before the association (we end up calling
  `uniq!` on the errors in the autosave validation)
- Adding `accepts_nested_attributes_for` (I have no clue why. The only
  thing it does that should affect this is adds `autosave: true` to the
  inverse reflection, and doing that manually doesn't fix this).

This solution is a hack, and I'm almost certain there's a better way to
go about it, but this shouldn't cause a huge hit on validation times,
and is the simplest way to get it done.

Fixes #20874.

1 files changed, 7 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 47364325ea..997abcb48d 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Ensure that cyclic associations with autosave don't cause duplicate errors
+    to be added to the parent record.
+
+    Fixes #20874.
+
+    *Sean Griffin*
+
 *   Ensure that `ActionController::Parameters` can still be passed to nested
     attributes.