Fix validations on child record when record parent has validate: false

Fixes #17621. This 5 year old (or older) issue causes validations to fire
when a parent record has `validate: false` option and a child record is
saved. It's not the responsibility of the model to validate an
associated object unless the object was created or modified by the
parent.

Clean up tests related to validations

`assert_nothing_raised` is not benefiting us in these tests
Corrected spelling of "respects"
It's better to use `assert_not_operator` over `assert !r.valid`

1 files changed, 12 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index a17148f1f7..3a0c32e66d 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,15 @@
+*   Validation errors would be raised for parent records when an association
+    was saved when the parent had `validate: false`. It should not be the
+    responsibility of the model to validate an associated object unless the
+    object was created or modified by the parent.
+
+    This fixes the issue by skipping validations if the parent record is
+    persisted, not changed, and not marked for destruction.
+
+    Fixes #17621.
+
+    *Eileen M. Uchitelle, Aaron Patterson*
+
 *   Fix n+1 query problem when eager loading nil associations (fixes #18312)
 
     *Sammy Larbi*