Reset cache_versions on relation

Currently, when #reset is called on a relation object it does not reset
the cache_versions ivar. This can lead to a confusing and buggy
situation where despite having the correct data the relation is still
reporting a stale cache_version. Resetting this ivar along with the
other relation state corrects this situation.

Update test assertion

Assert the specific cache_version matches the latest .all relation

Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>

activerecord/CHANGELOG.md

@@ -1,3 +1,26 @@
+*   Resolve issue where a relation cache_version could be left stale.
+
+    Previously, when `reset` was called on a relation object it did not reset the cache_versions
+    ivar. This led to a confusing situation where despite having the correct data the relation
+    still reported a stale cache_version.
+
+    Usage:
+
+    ```ruby
+    developers = Developer.all
+    developers.cache_version
+
+    Developer.update_all(updated_at: Time.now.utc + 1.second)
+
+    developers.cache_version # Stale cache_version
+    developers.reset
+    developers.cache_version # Returns the current correct cache_version
+    ```
+
+    Fixes #45341.
+
+    *Austen Madden*
+
 *   Add support for exclusion constraints (PostgreSQL-only).
 
     ```ruby

activerecord/lib/active_record/relation.rb

@@ -713,6 +713,7 @@ module ActiveRecord
       @to_sql = @arel = @loaded = @should_eager_load = nil
       @offsets = @take = nil
       @cache_keys = nil
+      @cache_versions = nil
       @records = nil
       self
     end

activerecord/test/cases/collection_cache_key_test.rb

@@ -254,6 +254,19 @@ module ActiveRecord
       end
     end
 
+    test "reset will reset cache_version" do
+      with_collection_cache_versioning do
+        developers = Developer.all
+
+        assert_equal Developer.all.cache_version, developers.cache_version
+
+        Developer.update_all(updated_at: Time.now.utc + 1.second)
+        developers.reset
+
+        assert_equal Developer.all.cache_version, developers.cache_version
+      end
+    end
+
     test "cache_key_with_version contains key and version regardless of collection_cache_versioning setting" do
       key_with_version_1 = Developer.all.cache_key_with_version
       assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\z/, key_with_version_1)